UPDATE: Webapp

Also integrated with CI and runs tests in documentation

.github/workflows/publish-wiki.yml

@@ -0,0 +1,18 @@
+name: Publish wiki
+on:
+  push:
+    branches: [main]
+    paths:
+      - wiki/**
+      - .github/workflows/publish-wiki.yml
+concurrency:
+  group: publish-wiki
+  cancel-in-progress: true
+permissions:
+  contents: write
+jobs:
+  publish-wiki:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: Andrew-Chen-Wang/github-wiki-action@v4

.github/workflows/rust-build-test.yaml

@@ -16,6 +16,9 @@ jobs:
         steps:
             - uses: actions/checkout@v3
 
+            - name: Install wasm-pack
+              run: curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
+
             - name: Build
               run: cargo build --release --verbose
 

.github/workflows/test-coverage.yaml

@@ -1,6 +1,6 @@
 name: Coverage
 
-on: [pull_request, push]
+on: [pull_request]
 
 jobs:
   coverage:
@@ -14,7 +14,7 @@ jobs:
       - name: Install cargo-llvm-cov
         uses: taiki-e/install-action@cargo-llvm-cov
       - name: Generate code coverage
-        run: cargo llvm-cov --all-features --workspace --lcov --output-path lcov.info
+        run: cargo llvm-cov --all-features --workspace --exclude pyroncalc --exclude wasm --lcov --output-path lcov.info
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v3
         with:

.gitignore

@@ -1 +1,2 @@
-target/*
+target/*
+.DS_Store

.readthedocs.yaml

@@ -0,0 +1,32 @@
+# .readthedocs.yaml
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required
+version: 2
+
+# Set the OS, Python version and other tools you might need
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.12"
+    # You can also specify other tool versions:
+    # nodejs: "19"
+    # rust: "1.64"
+    # golang: "1.19"
+
+# Build documentation in the "docs/" directory with Sphinx
+sphinx:
+  configuration: bindings/python/docs/conf.py
+
+# Optionally build your docs in additional formats such as PDF and ePub
+# formats:
+#    - pdf
+#    - epub
+
+# Optional but recommended, declare the Python requirements required
+# to build your documentation
+# See https://docs.readthedocs.io/en/stable/guides/reproducible-builds.html
+# python:
+#    install:
+#    - requirements: docs/requirements.txt

Cargo.toml

@@ -4,6 +4,8 @@ resolver = "2"
 members = [
   "base",
   "xlsx",
+  "bindings/wasm",
+  "bindings/python",
 ]
 
 exclude = [

Makefile

@@ -1,33 +1,53 @@
+.PHONY: lint
 lint:
 	cargo fmt -- --check
 	cargo clippy --all-targets --all-features
+	cd webapp && npm install && npm run check
 
+.PHONY: format
 format:
 	cargo fmt
 
+.PHONY: tests
 tests: lint
 	cargo test
-	make remove-xlsx
+	./target/debug/documentation
+	cmp functions.md wiki/functions.md || exit 1
+	make remove-artifacts
+	# Regretabbly we need to build the wasm twice, once for the nodejs tests
+	# and a second one for the vitest.
+	cd bindings/wasm/ && wasm-pack build --target nodejs && node tests/test.mjs && make
+	cd webapp && npm run test
+	cd bindings/python && ./run_tests.sh && ./run_examples.sh
 
-remove-xlsx:
+.PHONY: remove-artifacts
+remove-artifacts:
 	rm -f xlsx/hello-calc.xlsx
 	rm -f xlsx/hello-styles.xlsx
 	rm -f xlsx/widths-and-heights.xlsx
+	rm -f functions.md
 
-clean: remove-xlsx
+.PHONY: clean
+clean: remove-artifacts
 	cargo clean
 	rm -r -f base/target
 	rm -r -f xlsx/target
+	rm -r -f bindings/python/target
+	rm -r -f bindings/wasm/targets
 	rm -f cargo-test-*
 	rm -f base/cargo-test-*
 	rm -f xlsx/cargo-test-*
 
-
+.PHONY: coverage
 coverage:
 	CARGO_INCREMENTAL=0 RUSTFLAGS='-C instrument-coverage' LLVM_PROFILE_FILE='cargo-test-%p-%m.profraw' cargo test
 	grcov . --binary-path ./target/debug/deps/ -s . -t html --branch --ignore-not-existing --ignore '../*' --ignore "/*" -o target/coverage/html
 
+.PHONY: update-docs
+update-docs:
+	cargo build
+	./target/debug/documentation -o wiki/functions.md
+
+.PHONY: docs
 docs:
 	cargo doc --no-deps
-
-.PHONY: lint format tests docs coverage all

README.md

@@ -117,55 +117,7 @@ See more examples in the `examples` folder of the xlsx crate.
 
 # ROADMAP
 
-> [!WARNING]  
-> This is work-in-progress. IronCalc in developed in the open. Expect things to be broken and change quickly until version 0.5
-
-Major milestones:
-
-* MVP, version 0.5.0: We intend to have a working version by mid March 2024 (version 0.5, MVP)
-* Stable, version 1.0.0 will come later in December 2024
-
-MVP stands for _Minimum Viable Product_
-
-## Version 0.5 or MVP (early 2024)
-
-Version 0.5 includes the engine, javascript and nodejs bindings and a web application
-
-Features of the engine include:
-
-* Read and write xlsx files
-* API to set and read values from cells
-* Implemented 192 Excel functions
-* Time functions with timezones
-* Prepared for i18n but will only support English
-* Wide test coverage
-
-UI features of the web application (backed by the engine):
-
-* Enter values and formulas. Browse mode
-* Italics, bold, underline, horizontal alignment
-* Number formatting
-* Add/remove/rename sheets
-* Copy/Paste extend values
-* Keyboard navigation
-* Delete/Add rows and columns
-* Resize rows and columns
-* Correct scrolling and navigation
-
-## Version 1.0 or Stable (December 2024)
-
-Minor milestones in the ROADMAD for version 1.0.0 (engine and UI):
-
-* Implementation of arrays and array formulas
-* Formula documentation and context help
-* Merge cells
-* Pivot tables
-* Define name manager (mostly UI)
-* Update main evaluation algorithm with a support graph
-* Dynamic arrays (SORT, UNIQUE, ..)
-* Full i18n support with different locales and languages
-* Python bindings
-* Full test coverage
+See https://github.com/ironcalc
 
 # Early testing
 
@@ -176,7 +128,7 @@ https://playground.ironcalc.com
 
 # Collaborators needed!. Call to action
 
-We don't have a vibrant community just yet. This is the very stages of the project. But if you are passionate about code with high standards and no compromises, if you are looking for a project with high impact, if you are interested in a better, more open infrastructure for spreadsheets, whether you are a developer (rust, python, TypeScript, electron/tauri/anything else native app, React, you name it), a designer (we need a logo desperately!), an Excel power user who wants features, a business looking to integrate a MIT/Apache licensed spreadsheet in your own SaaS application join us!
+We don't have a vibrant community just yet. This is the very stages of the project. But if you are passionate about code with high standards and no compromises, if you are looking for a project with high impact, if you are interested in a better, more open infrastructure for spreadsheets, whether you are a developer (rust, python, TypeScript, electron/tauri/anything else native app, React, you name it), a designer, an Excel power user who wants features, a business looking to integrate a MIT/Apache licensed spreadsheet in your own SaaS application join us!
 
 The best place to start will be to join or [discord channel](https://discord.gg/zZYWfh3RHJ) or send us an email at hello@ironcalc.com.
 
@@ -192,4 +144,4 @@ Licensed under either of
 * [MIT license](LICENSE-MIT)
 * [Apache license, version 2.0](LICENSE-Apache-2.0)
 
-at your option.
+at your option.

assets/icon/ironcalc_icon.svg

@@ -0,0 +1,8 @@
+<svg width="600" height="600" viewBox="0 0 600 600" fill="none" xmlns="http://www.w3.org/2000/svg">
+<rect width="600" height="600" rx="20" fill="#F2994A"/>
+<path opacity="0.8" fill-rule="evenodd" clip-rule="evenodd" d="M348.98 100C348.98 166.034 322.748 229.362 276.055 276.055C268.163 283.947 259.796 291.255 251.021 297.95L251.021 500L348.98 500H251.021C251.021 433.966 277.252 370.637 323.945 323.945C331.837 316.053 340.204 308.745 348.98 302.05L348.98 100Z" fill="white"/>
+<path opacity="0.8" fill-rule="evenodd" clip-rule="evenodd" d="M251.021 100.068C251.003 140.096 235.094 178.481 206.788 206.787C178.466 235.109 140.053 251.02 100 251.02V348.979C154.873 348.979 207.877 330.866 251.021 297.95V100.068Z" fill="white"/>
+<path opacity="0.8" fill-rule="evenodd" clip-rule="evenodd" d="M348.98 499.882C349.011 459.872 364.918 421.507 393.213 393.213C421.534 364.891 459.947 348.98 500 348.98V251.02C445.128 251.02 392.123 269.134 348.98 302.05V499.882Z" fill="white"/>
+<path fill-rule="evenodd" clip-rule="evenodd" d="M276.055 276.055C322.748 229.362 348.98 166.034 348.98 100H251.021V297.95C259.796 291.255 268.163 283.947 276.055 276.055Z" fill="white"/>
+<path fill-rule="evenodd" clip-rule="evenodd" d="M348.98 302.05V499.895C348.98 499.93 348.98 499.965 348.98 500L251.021 500C251.021 499.946 251.02 499.891 251.021 499.837C251.064 433.862 277.291 370.599 323.945 323.945C331.837 316.053 340.204 308.745 348.98 302.05Z" fill="white"/>
+</svg>

base/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ironcalc_base"
-version = "0.1.2"
+version = "0.2.0"
 authors = ["Nicolás Hatcher <nicolas@theuniverse.today>"]
 edition = "2021"
 homepage = "https://www.ironcalc.com"
@@ -12,18 +12,20 @@ readme = "README.md"
 
 [dependencies]
 serde = { version = "1.0", features = ["derive"] }
-serde_json = "1.0"
-serde_repr = "0.1"
 ryu = "1.0"
 chrono = "0.4"
-chrono-tz = "0.7.0"
+chrono-tz = "0.9"
 regex = "1.0"
 once_cell = "1.16.0"
+bitcode = "0.6.0"
+
+[dev-dependencies]
+serde_json = "1.0"
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
-js-sys = { version = "0.3.60" }
+js-sys = { version = "0.3.69" }
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
-rand = "0.8.4"
+rand = "0.8.5"
 
 

base/examples/formulas_and_errors.rs

@@ -1,17 +1,17 @@
-use ironcalc_base::{model::Model, types::CellType};
+use ironcalc_base::{types::CellType, Model};
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let mut model = Model::new_empty("formulas-and-errors", "en", "UTC")?;
     // A1
-    model.set_user_input(0, 1, 1, "1".to_string());
+    model.set_user_input(0, 1, 1, "1".to_string())?;
     // A2
-    model.set_user_input(0, 2, 1, "2".to_string());
+    model.set_user_input(0, 2, 1, "2".to_string())?;
     // A3
-    model.set_user_input(0, 3, 1, "3".to_string());
+    model.set_user_input(0, 3, 1, "3".to_string())?;
     // B1
-    model.set_user_input(0, 1, 2, "=SUM(A1:A3)".to_string());
+    model.set_user_input(0, 1, 2, "=SUM(A1:A3)".to_string())?;
     // B2
-    model.set_user_input(0, 2, 2, "=B1/0".to_string());
+    model.set_user_input(0, 2, 2, "=B1/0".to_string())?;
     // Evaluate
     model.evaluate();
 

base/examples/hello_world.rs

@@ -1,13 +1,13 @@
-use ironcalc_base::{cell::CellValue, model::Model};
+use ironcalc_base::{cell::CellValue, Model};
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     let mut model = Model::new_empty("hello-world", "en", "UTC")?;
     // A1
-    model.set_user_input(0, 1, 1, "Hello".to_string());
+    model.set_user_input(0, 1, 1, "Hello".to_string())?;
     // B1
-    model.set_user_input(0, 1, 2, "world!".to_string());
+    model.set_user_input(0, 1, 2, "world!".to_string())?;
     // C1
-    model.set_user_input(0, 1, 3, "=CONCAT(A1, \" \", B1".to_string());
+    model.set_user_input(0, 1, 3, "=CONCAT(A1, \" \", B1".to_string())?;
     // evaluates
     model.evaluate();
 

base/src/actions.rs

@@ -77,14 +77,13 @@ impl Model {
         let style = source_cell.get_style();
         // FIXME: we need some user_input getter instead of get_text
         let formula_or_value = self
-            .cell_formula(sheet, source_row, source_column)?
+            .get_cell_formula(sheet, source_row, source_column)?
             .unwrap_or_else(|| source_cell.get_text(&self.workbook.shared_strings, &self.language));
-        self.set_user_input(sheet, target_row, target_column, formula_or_value);
+        self.set_user_input(sheet, target_row, target_column, formula_or_value)?;
         self.workbook
             .worksheet_mut(sheet)?
-            .set_cell_style(target_row, target_column, style);
-        self.delete_cell(sheet, source_row, source_column)?;
-        Ok(())
+            .set_cell_style(target_row, target_column, style)?;
+        self.cell_clear_all(sheet, source_row, source_column)
     }
 
     /// Inserts one or more new columns into the model at the specified index.
@@ -157,6 +156,11 @@ impl Model {
             return Err("Please use insert columns instead".to_string());
         }
 
+        // first column being deleted
+        let column_start = column;
+        // last column being deleted
+        let column_end = column + column_count - 1;
+
         // Move cells
         let worksheet = &self.workbook.worksheet(sheet)?;
         let mut all_rows: Vec<i32> = worksheet.sheet_data.keys().copied().collect();
@@ -166,11 +170,11 @@ impl Model {
         for r in all_rows {
             let columns: Vec<i32> = self.get_columns_for_row(sheet, r, false)?;
             for col in columns {
-                if col >= column {
-                    if col >= column + column_count {
+                if col >= column_start {
+                    if col > column_end {
                         self.move_cell(sheet, r, col, r, col - column_count)?;
                     } else {
-                        self.delete_cell(sheet, r, col)?;
+                        self.cell_clear_all(sheet, r, col)?;
                     }
                 }
             }
@@ -184,6 +188,64 @@ impl Model {
                 delta: -column_count,
             }),
         );
+        let worksheet = &mut self.workbook.worksheet_mut(sheet)?;
+
+        // deletes all the column styles
+        let mut new_columns = Vec::new();
+        for col in worksheet.cols.iter_mut() {
+            // range under study
+            let min = col.min;
+            let max = col.max;
+            // In the diagram:
+            // |xxxxx| range we are studying [min, max]
+            // |*****| range we are deleting [column_start, column_end]
+            // we are going to split it in three big cases:
+            // ----------------|xxxxxxxx|-----------------
+            // -----|*****|------------------------------- Case A
+            // -------|**********|------------------------ Case B
+            // -------------|**************|-------------- Case C
+            // ------------------|****|------------------- Case D
+            // ---------------------|**********|---------- Case E
+            // -----------------------------|*****|------- Case F
+            if column_start < min {
+                if column_end < min {
+                    // Case A
+                    // We displace all columns
+                    let mut new_column = col.clone();
+                    new_column.min = min - column_count;
+                    new_column.max = max - column_count;
+                    new_columns.push(new_column);
+                } else if column_end < max {
+                    // Case B
+                    // We displace the end
+                    let mut new_column = col.clone();
+                    new_column.min = column_start;
+                    new_column.max = max - column_count;
+                    new_columns.push(new_column);
+                } else {
+                    // Case C
+                    // skip this, we are deleting the whole range
+                }
+            } else if column_start <= max {
+                if column_end <= max {
+                    // Case D
+                    // We displace the end
+                    let mut new_column = col.clone();
+                    new_column.max = max - column_count;
+                    new_columns.push(new_column);
+                } else {
+                    // Case E
+                    let mut new_column = col.clone();
+                    new_column.max = column_start - 1;
+                    new_columns.push(new_column);
+                }
+            } else {
+                // Case F
+                // No action required
+                new_columns.push(col.clone());
+            }
+        }
+        worksheet.cols = new_columns;
 
         Ok(())
     }
@@ -283,7 +345,7 @@ impl Model {
                     // remove all cells in row
                     // FIXME: We could just remove the entire row in one go
                     for column in columns {
-                        self.delete_cell(sheet, r, column)?;
+                        self.cell_clear_all(sheet, r, column)?;
                     }
                 }
             }

base/src/cell.rs

@@ -1,12 +1,9 @@
 use crate::{
     expressions::token::Error, language::Language, number_format::to_excel_precision_str, types::*,
 };
-use serde::{Deserialize, Serialize};
-use serde_json::json;
 
 /// A CellValue is the representation of the cell content.
-#[derive(Serialize, Deserialize, Debug, PartialEq)]
-#[serde(untagged)]
+#[derive(Debug, PartialEq)]
 pub enum CellValue {
     None,
     String(String),
@@ -14,17 +11,6 @@ pub enum CellValue {
     Boolean(bool),
 }
 
-impl CellValue {
-    pub fn to_json_str(&self) -> String {
-        match &self {
-            CellValue::None => "null".to_string(),
-            CellValue::String(s) => json!(s).to_string(),
-            CellValue::Number(f) => json!(f).to_string(),
-            CellValue::Boolean(b) => json!(b).to_string(),
-        }
-    }
-}
-
 impl From<f64> for CellValue {
     fn from(value: f64) -> Self {
         Self::Number(value)

base/src/constants.rs

@@ -6,6 +6,8 @@ pub(crate) const DEFAULT_COLUMN_WIDTH: f64 = 100.0;
 pub(crate) const DEFAULT_ROW_HEIGHT: f64 = 21.0;
 pub(crate) const COLUMN_WIDTH_FACTOR: f64 = 12.0;
 pub(crate) const ROW_HEIGHT_FACTOR: f64 = 2.0;
+pub(crate) const DEFAULT_WINDOW_HEIGH: i64 = 600;
+pub(crate) const DEFAULT_WINDOW_WIDTH: i64 = 800;
 
 pub(crate) const LAST_COLUMN: i32 = 16_384;
 pub(crate) const LAST_ROW: i32 = 1_048_576;

base/src/expressions/lexer/mod.rs

@@ -308,9 +308,9 @@ impl Lexer {
                                 return self.consume_range(None);
                             }
                             let name_upper = name.to_ascii_uppercase();
-                            if name_upper == self.language.booleans.true_value {
+                            if name_upper == self.language.booleans.r#true {
                                 return TokenType::Boolean(true);
-                            } else if name_upper == self.language.booleans.false_value {
+                            } else if name_upper == self.language.booleans.r#false {
                                 return TokenType::Boolean(false);
                             }
                             if self.mode == LexerMode::A1 {
@@ -660,8 +660,8 @@ impl Lexer {
     fn consume_error(&mut self) -> TokenType {
         let errors = &self.language.errors;
         let rest_of_formula: String = self.chars[self.position - 1..self.len].iter().collect();
-        if rest_of_formula.starts_with(&errors.ref_value) {
-            self.position += errors.ref_value.chars().count() - 1;
+        if rest_of_formula.starts_with(&errors.r#ref) {
+            self.position += errors.r#ref.chars().count() - 1;
             return TokenType::Error(Error::REF);
         } else if rest_of_formula.starts_with(&errors.name) {
             self.position += errors.name.chars().count() - 1;

base/src/expressions/lexer/test/test_locale.rs

@@ -6,11 +6,11 @@ use crate::{
         token::TokenType,
     },
     language::get_language,
-    locale::get_locale_fix,
+    locale::get_locale,
 };
 
 fn new_language_lexer(formula: &str, locale: &str, language: &str) -> Lexer {
-    let locale = get_locale_fix(locale).unwrap();
+    let locale = get_locale(locale).unwrap();
     let language = get_language(language).unwrap();
     Lexer::new(formula, LexerMode::A1, locale, language)
 }

base/src/expressions/parser/mod.rs

@@ -222,7 +222,7 @@ impl Parser {
 
     pub fn parse(&mut self, formula: &str, context: &Option<CellReferenceRC>) -> Node {
         self.lexer.set_formula(formula);
-        self.context = context.clone();
+        self.context.clone_from(context);
         self.parse_expr()
     }
 

base/src/expressions/token.rs

@@ -1,7 +1,7 @@
 use std::fmt;
 
+use bitcode::{Decode, Encode};
 use serde::{Deserialize, Serialize};
-use serde_repr::{Deserialize_repr, Serialize_repr};
 
 use crate::language::Language;
 
@@ -80,8 +80,7 @@ impl fmt::Display for OpProduct {
 ///  * "#ERROR!" means there was an error processing the formula (for instance "=A1+")
 ///  * "#N/IMPL!" means the formula or feature in Excel but has not been implemented in IronCalc
 /// Note that they are serialized/deserialized by index
-#[derive(Serialize_repr, Deserialize_repr, Debug, PartialEq, Eq, Clone)]
-#[repr(u8)]
+#[derive(Serialize, Deserialize, Encode, Decode, Debug, PartialEq, Eq, Clone)]
 pub enum Error {
     REF,
     NAME,
@@ -119,7 +118,7 @@ impl Error {
     pub fn to_localized_error_string(&self, language: &Language) -> String {
         match self {
             Error::NULL => language.errors.null.to_string(),
-            Error::REF => language.errors.ref_value.to_string(),
+            Error::REF => language.errors.r#ref.to_string(),
             Error::NAME => language.errors.name.to_string(),
             Error::VALUE => language.errors.value.to_string(),
             Error::DIV => language.errors.div.to_string(),
@@ -136,7 +135,7 @@ impl Error {
 
 pub fn get_error_by_name(name: &str, language: &Language) -> Option<Error> {
     let errors = &language.errors;
-    if name == errors.ref_value {
+    if name == errors.r#ref {
         return Some(Error::REF);
     } else if name == errors.name {
         return Some(Error::NAME);

base/src/functions/date_and_time.rs

@@ -1,7 +1,6 @@
+use chrono::DateTime;
 use chrono::Datelike;
 use chrono::Months;
-use chrono::NaiveDateTime;
-use chrono::TimeZone;
 use chrono::Timelike;
 
 use crate::expressions::types::CellReferenceIndex;
@@ -258,8 +257,8 @@ impl Model {
         // milliseconds since January 1, 1970 00:00:00 UTC.
         let milliseconds = get_milliseconds_since_epoch();
         let seconds = milliseconds / 1000;
-        let dt = match NaiveDateTime::from_timestamp_opt(seconds, 0) {
-            Some(dt) => dt,
+        let local_time = match DateTime::from_timestamp(seconds, 0) {
+            Some(dt) => dt.with_timezone(&self.tz),
             None => {
                 return CalcResult::Error {
                     error: Error::ERROR,
@@ -268,7 +267,6 @@ impl Model {
                 }
             }
         };
-        let local_time = self.tz.from_utc_datetime(&dt);
         // 693_594 is computed as:
         // NaiveDate::from_ymd(1900, 1, 1).num_days_from_ce() - 2
         // The 2 days offset is because of Excel 1900 bug
@@ -289,8 +287,8 @@ impl Model {
         // milliseconds since January 1, 1970 00:00:00 UTC.
         let milliseconds = get_milliseconds_since_epoch();
         let seconds = milliseconds / 1000;
-        let dt = match NaiveDateTime::from_timestamp_opt(seconds, 0) {
-            Some(dt) => dt,
+        let local_time = match DateTime::from_timestamp(seconds, 0) {
+            Some(dt) => dt.with_timezone(&self.tz),
             None => {
                 return CalcResult::Error {
                     error: Error::ERROR,
@@ -299,7 +297,6 @@ impl Model {
                 }
             }
         };
-        let local_time = self.tz.from_utc_datetime(&dt);
         // 693_594 is computed as:
         // NaiveDate::from_ymd(1900, 1, 1).num_days_from_ce() - 2
         // The 2 days offset is because of Excel 1900 bug

base/src/functions/information.rs

@@ -165,7 +165,8 @@ impl Model {
                     message: "argument must be a reference to a single cell".to_string(),
                 };
             }
-            let is_formula = if let Ok(f) = self.cell_formula(left.sheet, left.row, left.column) {
+            let is_formula = if let Ok(f) = self.get_cell_formula(left.sheet, left.row, left.column)
+            {
                 f.is_some()
             } else {
                 false

base/src/functions/mod.rs

@@ -1,4 +1,5 @@
 use core::fmt;
+use std::array::IntoIter;
 
 use crate::{
     calc_result::CalcResult,
@@ -244,6 +245,206 @@ pub enum Function {
     Subtotal,
 }
 
+impl Function {
+    pub fn into_iter() -> IntoIter<Function, 192> {
+        [
+            Function::And,
+            Function::False,
+            Function::If,
+            Function::Iferror,
+            Function::Ifna,
+            Function::Ifs,
+            Function::Not,
+            Function::Or,
+            Function::Switch,
+            Function::True,
+            Function::Xor,
+            Function::Sin,
+            Function::Cos,
+            Function::Tan,
+            Function::Asin,
+            Function::Acos,
+            Function::Atan,
+            Function::Sinh,
+            Function::Cosh,
+            Function::Tanh,
+            Function::Asinh,
+            Function::Acosh,
+            Function::Atanh,
+            Function::Abs,
+            Function::Pi,
+            Function::Sqrt,
+            Function::Sqrtpi,
+            Function::Atan2,
+            Function::Power,
+            Function::Max,
+            Function::Min,
+            Function::Product,
+            Function::Rand,
+            Function::Randbetween,
+            Function::Round,
+            Function::Rounddown,
+            Function::Roundup,
+            Function::Sum,
+            Function::Sumif,
+            Function::Sumifs,
+            Function::Choose,
+            Function::Column,
+            Function::Columns,
+            Function::Index,
+            Function::Indirect,
+            Function::Hlookup,
+            Function::Lookup,
+            Function::Match,
+            Function::Offset,
+            Function::Row,
+            Function::Rows,
+            Function::Vlookup,
+            Function::Xlookup,
+            Function::Concatenate,
+            Function::Exact,
+            Function::Value,
+            Function::T,
+            Function::Valuetotext,
+            Function::Concat,
+            Function::Find,
+            Function::Left,
+            Function::Len,
+            Function::Lower,
+            Function::Mid,
+            Function::Right,
+            Function::Search,
+            Function::Text,
+            Function::Trim,
+            Function::Upper,
+            Function::Isnumber,
+            Function::Isnontext,
+            Function::Istext,
+            Function::Islogical,
+            Function::Isblank,
+            Function::Iserr,
+            Function::Iserror,
+            Function::Isna,
+            Function::Na,
+            Function::Isref,
+            Function::Isodd,
+            Function::Iseven,
+            Function::ErrorType,
+            Function::Isformula,
+            Function::Type,
+            Function::Sheet,
+            Function::Average,
+            Function::Averagea,
+            Function::Averageif,
+            Function::Averageifs,
+            Function::Count,
+            Function::Counta,
+            Function::Countblank,
+            Function::Countif,
+            Function::Countifs,
+            Function::Maxifs,
+            Function::Minifs,
+            Function::Year,
+            Function::Day,
+            Function::Month,
+            Function::Eomonth,
+            Function::Date,
+            Function::Edate,
+            Function::Today,
+            Function::Now,
+            Function::Pmt,
+            Function::Pv,
+            Function::Rate,
+            Function::Nper,
+            Function::Fv,
+            Function::Ppmt,
+            Function::Ipmt,
+            Function::Npv,
+            Function::Mirr,
+            Function::Irr,
+            Function::Xirr,
+            Function::Xnpv,
+            Function::Rept,
+            Function::Textafter,
+            Function::Textbefore,
+            Function::Textjoin,
+            Function::Substitute,
+            Function::Ispmt,
+            Function::Rri,
+            Function::Sln,
+            Function::Syd,
+            Function::Nominal,
+            Function::Effect,
+            Function::Pduration,
+            Function::Tbillyield,
+            Function::Tbillprice,
+            Function::Tbilleq,
+            Function::Dollarde,
+            Function::Dollarfr,
+            Function::Ddb,
+            Function::Db,
+            Function::Cumprinc,
+            Function::Cumipmt,
+            Function::Besseli,
+            Function::Besselj,
+            Function::Besselk,
+            Function::Bessely,
+            Function::Erf,
+            Function::ErfPrecise,
+            Function::Erfc,
+            Function::ErfcPrecise,
+            Function::Bin2dec,
+            Function::Bin2hex,
+            Function::Bin2oct,
+            Function::Dec2Bin,
+            Function::Dec2hex,
+            Function::Dec2oct,
+            Function::Hex2bin,
+            Function::Hex2dec,
+            Function::Hex2oct,
+            Function::Oct2bin,
+            Function::Oct2dec,
+            Function::Oct2hex,
+            Function::Bitand,
+            Function::Bitlshift,
+            Function::Bitor,
+            Function::Bitrshift,
+            Function::Bitxor,
+            Function::Complex,
+            Function::Imabs,
+            Function::Imaginary,
+            Function::Imargument,
+            Function::Imconjugate,
+            Function::Imcos,
+            Function::Imcosh,
+            Function::Imcot,
+            Function::Imcsc,
+            Function::Imcsch,
+            Function::Imdiv,
+            Function::Imexp,
+            Function::Imln,
+            Function::Imlog10,
+            Function::Imlog2,
+            Function::Impower,
+            Function::Improduct,
+            Function::Imreal,
+            Function::Imsec,
+            Function::Imsech,
+            Function::Imsin,
+            Function::Imsinh,
+            Function::Imsqrt,
+            Function::Imsub,
+            Function::Imsum,
+            Function::Imtan,
+            Function::Convert,
+            Function::Delta,
+            Function::Gestep,
+            Function::Subtotal,
+        ]
+        .into_iter()
+    }
+}
+
 impl Function {
     /// Some functions in Excel like CONCAT are stringified as `_xlfn.CONCAT`.
     pub fn to_xlsx_string(&self) -> String {
@@ -708,7 +909,23 @@ impl fmt::Display for Function {
     }
 }
 
+/// Documentation for one function
+pub struct Documentation {
+    pub name: String,
+}
+
 impl Model {
+    /// Produces documentation for all implemented functions
+    pub fn documentation() -> Vec<Documentation> {
+        let mut doc = Vec::new();
+        for function in Function::into_iter() {
+            doc.push(Documentation {
+                name: function.to_string(),
+            });
+        }
+        doc
+    }
+
     pub(crate) fn evaluate_function(
         &mut self,
         kind: &Function,
@@ -928,3 +1145,66 @@ impl Model {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use std::{
+        fs::File,
+        io::{BufRead, BufReader},
+    };
+
+    use crate::functions::Function;
+
+    #[test]
+    fn function_iterator() {
+        // This checks that the number of functions in the enum is the same
+        // as the number of functions in the Iterator.
+
+        // This is tricky. In Rust we cannot loop over all the members of an enum.
+        // There are alternatives like using an external crate like strum.
+        // But I am not in the mood for that.
+
+        // What we do here is read this file , extract the functions in the enum
+        // and check they are the same as in the iterator
+        let file = File::open("src/functions/mod.rs").unwrap();
+        let reader = BufReader::new(file);
+        let mut start = false;
+        let mut list = Vec::new();
+
+        for line in reader.lines() {
+            let text = line.unwrap();
+            let text = text.trim().trim_end_matches(',');
+            if text == "pub enum Function {" {
+                start = true;
+                continue;
+            }
+            if start {
+                if text == "}" {
+                    break;
+                }
+                if text.starts_with("//") {
+                    // skip comments
+                    continue;
+                }
+                if text.is_empty() {
+                    // skip empty lines
+                    continue;
+                }
+                list.push(text.to_owned());
+            }
+        }
+        // We make a list with their functions names, but we escape ".": ERROR.TYPE => ERRORTYPE
+        let iter_list = Function::into_iter()
+            .map(|f| format!("{}", f).replace('.', ""))
+            .collect::<Vec<_>>();
+
+        let len = iter_list.len();
+
+        assert_eq!(list.len(), len);
+        // We still need to check there are no duplicates. This will fail if a function in iter_list
+        // is included twice and one is missing
+        for function in list {
+            assert!(iter_list.contains(&function.to_uppercase()));
+        }
+    }
+}

base/src/garbage_collector.rs

@@ -1,12 +0,0 @@
-use crate::model::Model;
-
-// The gc (Garbage Collector) cleans up leftover elements in the workbook:
-// * Strings that are no longe reachable
-// * Styles that are no longer reachable
-// * ...
-
-impl Model {
-    pub(crate) fn gc(&mut self) -> Result<(), String> {
-        todo!()
-    }
-}

base/src/language/language.bin

@@ -0,0 +1 @@
+PfrendeesD<>VRAITRUEWAHRVERDADEROTVFAUXFALSEFALSCHFALSOUw#REF!#REF!#BEZUG!#¡REF!e<>#NOM?#NAME?#NAME?#¿NOMBRE?x<>#VALEUR!#VALUE!#WERT!#¡VALOR!w<>#DIV/0!#DIV/0!#DIV/0!#¡DIV/0!<04>#N/A#N/A#NV#N/AXv#NOMBRE!#NUM!#ZAHL!#¡NUM!<02><>#N/IMPL!#N/IMPL!#N/IMPL!#N/IMPL!w{#SPILL!#SPILL!#ÜBERLAUF!#SPILL!ff#CALC!#CALC!#CALC!#CALC!ff#CIRC!#CIRC!#CIRC!#CIRC!ww#ERROR!#ERROR!#ERROR!#ERROR!ff#NULL!#NULL!#NULL!#NULL!

base/src/language/mod.rs

@@ -1,20 +1,17 @@
-use once_cell::sync::Lazy;
-use serde::{Deserialize, Serialize};
-
 use std::collections::HashMap;
 
-#[derive(Serialize, Deserialize, Clone)]
+use bitcode::{Decode, Encode};
+use once_cell::sync::Lazy;
+
+#[derive(Encode, Decode, Clone)]
 pub struct Booleans {
-    #[serde(rename = "true")]
-    pub true_value: String,
-    #[serde(rename = "false")]
-    pub false_value: String,
+    pub r#true: String,
+    pub r#false: String,
 }
 
-#[derive(Serialize, Deserialize, Clone)]
+#[derive(Encode, Decode, Clone)]
 pub struct Errors {
-    #[serde(rename = "ref")]
-    pub ref_value: String,
+    pub r#ref: String,
     pub name: String,
     pub value: String,
     pub div: String,
@@ -28,14 +25,14 @@ pub struct Errors {
     pub null: String,
 }
 
-#[derive(Serialize, Deserialize, Clone)]
+#[derive(Encode, Decode, Clone)]
 pub struct Language {
     pub booleans: Booleans,
     pub errors: Errors,
 }
 
 static LANGUAGES: Lazy<HashMap<String, Language>> = Lazy::new(|| {
-    serde_json::from_str(include_str!("language.json")).expect("Failed parsing language file")
+    bitcode::decode(include_bytes!("language.bin")).expect("Failed parsing language file")
 });
 
 pub fn get_language(id: &str) -> Result<&Language, String> {

base/src/lib.rs

@@ -8,7 +8,7 @@
 //!
 //! ```toml
 //! [dependencies]
-//! ironcalc_base = { git = "https://github.com/ironcalc/IronCalc", version = "0.1"}
+//! ironcalc_base = { git = "https://github.com/ironcalc/IronCalc" }
 //! ```
 //!
 //! <small> until version 0.5.0 you should use the git dependencies as stated </small>
@@ -31,29 +31,31 @@ pub mod expressions;
 pub mod formatter;
 pub mod language;
 pub mod locale;
-pub mod model;
 pub mod new_empty;
 pub mod number_format;
 pub mod types;
 pub mod worksheet;
 
-mod functions;
-
 mod actions;
 mod cast;
 mod constants;
-mod styles;
-
 mod diffs;
+mod functions;
 mod implicit_intersection;
-
+mod model;
+mod styles;
 mod units;
+mod user_model;
 mod utils;
 mod workbook;
-mod garbage_collector;
 
 #[cfg(test)]
 mod test;
 
 #[cfg(test)]
 pub mod mock_time;
+
+pub use model::get_milliseconds_since_epoch;
+pub use model::Model;
+pub use user_model::BorderArea;
+pub use user_model::UserModel;

base/src/locale/mod.rs

@@ -1,32 +1,29 @@
+use bitcode::{Decode, Encode};
 use once_cell::sync::Lazy;
-use serde::{Deserialize, Serialize};
 
 use std::collections::HashMap;
 
-#[derive(Serialize, Deserialize, Clone)]
+#[derive(Encode, Decode, Clone)]
 pub struct Locale {
     pub dates: Dates,
     pub numbers: NumbersProperties,
     pub currency: Currency,
 }
 
-#[derive(Serialize, Deserialize, Clone)]
+#[derive(Encode, Decode, Clone)]
 pub struct Currency {
     pub iso: String,
     pub symbol: String,
 }
 
-#[derive(Serialize, Deserialize, Clone)]
+#[derive(Encode, Decode, Clone)]
 pub struct NumbersProperties {
-    #[serde(rename = "symbols-numberSystem-latn")]
     pub symbols: NumbersSymbols,
-    #[serde(rename = "decimalFormats-numberSystem-latn")]
     pub decimal_formats: DecimalFormats,
-    #[serde(rename = "currencyFormats-numberSystem-latn")]
     pub currency_formats: CurrencyFormats,
 }
 
-#[derive(Serialize, Deserialize, Clone)]
+#[derive(Encode, Decode, Clone)]
 pub struct Dates {
     pub day_names: Vec<String>,
     pub day_names_short: Vec<String>,
@@ -35,8 +32,7 @@ pub struct Dates {
     pub months_letter: Vec<String>,
 }
 
-#[derive(Serialize, Deserialize, Clone)]
-#[serde(rename_all = "camelCase")]
+#[derive(Encode, Decode, Clone)]
 pub struct NumbersSymbols {
     pub decimal: String,
     pub group: String,
@@ -54,40 +50,26 @@ pub struct NumbersSymbols {
 }
 
 // See: https://cldr.unicode.org/translation/number-currency-formats/number-and-currency-patterns
-#[derive(Serialize, Deserialize, Clone)]
+#[derive(Encode, Decode, Clone)]
 pub struct CurrencyFormats {
     pub standard: String,
-    #[serde(rename = "standard-alphaNextToNumber")]
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub standard_alpha_next_to_number: Option<String>,
-    #[serde(rename = "standard-noCurrency")]
     pub standard_no_currency: String,
     pub accounting: String,
-    #[serde(rename = "accounting-alphaNextToNumber")]
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub accounting_alpha_next_to_number: Option<String>,
-    #[serde(rename = "accounting-noCurrency")]
     pub accounting_no_currency: String,
 }
 
-#[derive(Serialize, Deserialize, Clone)]
-#[serde(rename_all = "camelCase")]
+#[derive(Encode, Decode, Clone)]
 pub struct DecimalFormats {
     pub standard: String,
 }
 
-static LOCALES: Lazy<HashMap<String, Locale>> = Lazy::new(|| {
-    serde_json::from_str(include_str!("locales.json")).expect("Failed parsing locale")
-});
+static LOCALES: Lazy<HashMap<String, Locale>> =
+    Lazy::new(|| bitcode::decode(include_bytes!("locales.bin")).expect("Failed parsing locale"));
 
-pub fn get_locale(_id: &str) -> Result<&Locale, String> {
+pub fn get_locale(id: &str) -> Result<&Locale, String> {
     // TODO: pass the locale once we implement locales in Rust
-    let locale = LOCALES.get("en").ok_or("Invalid locale")?;
-    Ok(locale)
-}
-
-// TODO: Remove this function one we implement locales properly
-pub fn get_locale_fix(id: &str) -> Result<&Locale, String> {
     let locale = LOCALES.get(id).ok_or("Invalid locale")?;
     Ok(locale)
 }

base/src/mock_time.rs

@@ -10,7 +10,7 @@ use std::cell::RefCell;
 // 8 November 2022 12:13 Berlin time
 
 thread_local! {
-    static MOCK_TIME: RefCell<i64> = RefCell::new(1667906008578);
+    static MOCK_TIME: RefCell<i64> = const { RefCell::new(1667906008578) };
 }
 
 pub fn get_milliseconds_since_epoch() -> i64 {
@@ -20,3 +20,18 @@ pub fn get_milliseconds_since_epoch() -> i64 {
 pub fn set_mock_time(time: i64) {
     MOCK_TIME.with(|cell| *cell.borrow_mut() = time);
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::mock_time::MOCK_TIME;
+
+    use super::get_milliseconds_since_epoch;
+
+    #[test]
+    fn mock_time() {
+        let t = get_milliseconds_since_epoch();
+        assert_eq!(t, 1667906008578);
+
+        MOCK_TIME.with_borrow(|v| assert_eq!(*v, 1667906008578));
+    }
+}

base/src/model.rs

@@ -1,14 +1,5 @@
 #![deny(missing_docs)]
 
-//! # Model
-//!
-//! Note that sheets are 0-indexed and rows and columns are 1-indexed.
-//!
-//! IronCalc is row first. A cell is referenced by (`sheet`, `row`, `column`)
-//!
-
-use serde_json::json;
-
 use std::collections::HashMap;
 use std::vec::Vec;
 
@@ -16,19 +7,15 @@ use crate::{
     calc_result::{CalcResult, Range},
     cell::CellValue,
     constants::{self, LAST_COLUMN, LAST_ROW},
-    expressions::token::{Error, OpCompare, OpProduct, OpSum, OpUnary},
-    expressions::{
-        parser::move_formula::{move_formula, MoveContext},
-        token::get_error_by_name,
-        types::*,
-        utils::{self, is_valid_row},
-    },
     expressions::{
         parser::{
+            move_formula::{move_formula, MoveContext},
             stringify::{to_rc_format, to_string},
             Node, Parser,
         },
-        utils::is_valid_column_number,
+        token::{get_error_by_name, Error, OpCompare, OpProduct, OpSum, OpUnary},
+        types::*,
+        utils::{self, is_valid_column_number, is_valid_row},
     },
     formatter::{
         format::{format_number, parse_formatted_number},
@@ -47,7 +34,11 @@ use chrono_tz::Tz;
 #[cfg(test)]
 pub use crate::mock_time::get_milliseconds_since_epoch;
 
-/// wasm implementation for time
+/// Number of milliseconds since January 1, 1970
+/// Used by time and date functions. It takes the value from the environment:
+/// * The Operative System
+/// * The JavaScript environment
+/// * Or mocked for tests
 #[cfg(not(test))]
 #[cfg(not(target_arch = "wasm32"))]
 pub fn get_milliseconds_since_epoch() -> i64 {
@@ -58,6 +49,11 @@ pub fn get_milliseconds_since_epoch() -> i64 {
         .as_millis() as i64
 }
 
+/// Number of milliseconds since January 1, 1970
+/// Used by time and date functions. It takes the value from the environment:
+/// * The Operative System
+/// * The JavaScript environment
+/// * Or mocked for tests
 #[cfg(not(test))]
 #[cfg(target_arch = "wasm32")]
 pub fn get_milliseconds_since_epoch() -> i64 {
@@ -67,7 +63,7 @@ pub fn get_milliseconds_since_epoch() -> i64 {
 
 /// A cell might be evaluated or being evaluated
 #[derive(Clone)]
-pub enum CellState {
+pub(crate) enum CellState {
     /// The cell has already been evaluated
     Evaluated,
     /// The cell is being evaluated
@@ -75,7 +71,7 @@ pub enum CellState {
 }
 
 /// A parsed formula for a defined name
-pub enum ParsedDefinedName {
+pub(crate) enum ParsedDefinedName {
     /// CellReference (`=C4`)
     CellReference(CellReferenceIndex),
     /// A Range (`=C4:D6`)
@@ -105,19 +101,21 @@ pub struct Model {
     /// A list of parsed formulas
     pub parsed_formulas: Vec<Vec<Node>>,
     /// A list of parsed defined names
-    pub parsed_defined_names: HashMap<(Option<u32>, String), ParsedDefinedName>,
+    pub(crate) parsed_defined_names: HashMap<(Option<u32>, String), ParsedDefinedName>,
     /// An optimization to lookup strings faster
-    pub shared_strings: HashMap<String, usize>,
+    pub(crate) shared_strings: HashMap<String, usize>,
     /// An instance of the parser
-    pub parser: Parser,
+    pub(crate) parser: Parser,
     /// The list of cells with formulas that are evaluated of being evaluated
-    pub cells: HashMap<(u32, i32, i32), CellState>,
+    pub(crate) cells: HashMap<(u32, i32, i32), CellState>,
     /// The locale of the model
-    pub locale: Locale,
+    pub(crate) locale: Locale,
     /// Tha language used
-    pub language: Language,
+    pub(crate) language: Language,
     /// The timezone used to evaluate the model
-    pub tz: Tz,
+    pub(crate) tz: Tz,
+    /// The view id. A view consist of a selected sheet and ranges.
+    pub(crate) view_id: u32,
 }
 
 // FIXME: Maybe this should be the same as CellReference
@@ -659,7 +657,7 @@ impl Model {
     /// # Examples
     ///
     /// ```rust
-    /// # use ironcalc_base::model::Model;
+    /// # use ironcalc_base::Model;
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// let mut model = Model::new_empty("model", "en", "UTC")?;
     /// assert_eq!(model.workbook.worksheet(0)?.color, None);
@@ -681,6 +679,13 @@ impl Model {
         Err(format!("Invalid color: {}", color))
     }
 
+    /// Makes the grid lines in the sheet visible (`true`) or hidden (`false`)
+    pub fn set_show_grid_lines(&mut self, sheet: u32, show_grid_lines: bool) -> Result<(), String> {
+        let worksheet = self.workbook.worksheet_mut(sheet)?;
+        worksheet.show_grid_lines = show_grid_lines;
+        Ok(())
+    }
+
     fn get_cell_value(&self, cell: &Cell, cell_reference: CellReferenceIndex) -> CalcResult {
         use Cell::*;
         match cell {
@@ -726,7 +731,7 @@ impl Model {
     /// # Examples
     ///
     /// ```rust
-    /// # use ironcalc_base::model::Model;
+    /// # use ironcalc_base::Model;
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// let mut model = Model::new_empty("model", "en", "UTC")?;
     /// assert_eq!(model.is_empty_cell(0, 1, 1)?, true);
@@ -798,17 +803,17 @@ impl Model {
         None
     }
 
-    /// Returns a model from a String representation of a workbook
+    /// Returns a model from an internal binary representation of a workbook
     ///
     /// # Examples
     ///
     /// ```rust
-    /// # use ironcalc_base::model::Model;
+    /// # use ironcalc_base::Model;
     /// # use ironcalc_base::cell::CellValue;
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// let mut model = Model::new_empty("model", "en", "UTC")?;
     /// model.set_user_input(0, 1, 1, "Stella!".to_string());
-    /// let model2 = Model::from_json(&model.to_json_str())?;
+    /// let model2 = Model::from_bytes(&model.to_bytes())?;
     /// assert_eq!(
     ///     model2.get_cell_value_by_index(0, 1, 1),
     ///     Ok(CellValue::String("Stella!".to_string()))
@@ -816,9 +821,12 @@ impl Model {
     /// # Ok(())
     /// # }
     /// ```
-    pub fn from_json(s: &str) -> Result<Model, String> {
+    ///
+    /// See also:
+    /// * [Model::to_bytes]
+    pub fn from_bytes(s: &[u8]) -> Result<Model, String> {
         let workbook: Workbook =
-            serde_json::from_str(s).map_err(|_| "Error parsing workbook".to_string())?;
+            bitcode::decode(s).map_err(|e| format!("Error parsing workbook: {e}"))?;
         Model::from_workbook(workbook)
     }
 
@@ -827,7 +835,7 @@ impl Model {
     /// # Examples
     ///
     /// ```rust
-    /// # use ironcalc_base::model::Model;
+    /// # use ironcalc_base::Model;
     /// # use ironcalc_base::cell::CellValue;
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// let mut model = Model::new_empty("model", "en", "UTC")?;
@@ -883,6 +891,7 @@ impl Model {
             language,
             locale,
             tz,
+            view_id: 0,
         };
 
         model.parse_formulas();
@@ -896,7 +905,7 @@ impl Model {
     /// # Examples
     ///
     /// ```rust
-    /// # use ironcalc_base::model::Model;
+    /// # use ironcalc_base::Model;
     /// # use ironcalc_base::expressions::types::CellReferenceIndex;
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// let mut model = Model::new_empty("model", "en", "UTC")?;
@@ -965,7 +974,7 @@ impl Model {
     /// # Examples
     ///
     /// ```rust
-    /// # use ironcalc_base::model::Model;
+    /// # use ironcalc_base::Model;
     /// # use ironcalc_base::expressions::types::{Area, CellReferenceIndex};
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// let mut model = Model::new_empty("model", "en", "UTC")?;
@@ -1036,7 +1045,7 @@ impl Model {
     /// # Examples
     ///
     /// ```rust
-    /// # use ironcalc_base::model::Model;
+    /// # use ironcalc_base::Model;
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// let mut model = Model::new_empty("model", "en", "UTC")?;
     /// let (sheet, row, column) = (0, 1, 1);
@@ -1083,7 +1092,7 @@ impl Model {
     /// # Examples
     ///
     /// ```rust
-    /// # use ironcalc_base::model::Model;
+    /// # use ironcalc_base::Model;
     /// # use ironcalc_base::expressions::types::CellReferenceIndex;
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// let mut model = Model::new_empty("model", "en", "UTC")?;
@@ -1138,13 +1147,13 @@ impl Model {
     /// # Examples
     ///
     /// ```rust
-    /// # use ironcalc_base::model::Model;
+    /// # use ironcalc_base::Model;
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// let mut model = Model::new_empty("model", "en", "UTC")?;
     /// let (sheet, row, column) = (0, 1, 1);
     /// model.set_user_input(sheet, row, column, "=SIN(B1*C3)+1".to_string());
     /// model.evaluate();
-    /// let result = model.cell_formula(sheet, row, column)?;
+    /// let result = model.get_cell_formula(sheet, row, column)?;
     /// assert_eq!(result, Some("=SIN(B1*C3)+1".to_string()));
     /// # Ok(())
     /// # }
@@ -1152,24 +1161,33 @@ impl Model {
     ///
     /// See also:
     /// * [Model::get_cell_content()]
-    pub fn cell_formula(
+    pub fn get_cell_formula(
         &self,
         sheet: u32,
         row: i32,
         column: i32,
     ) -> Result<Option<String>, String> {
         let worksheet = self.workbook.worksheet(sheet)?;
-        Ok(worksheet.cell(row, column).and_then(|cell| {
-            cell.get_formula().map(|formula_index| {
-                let formula = &self.parsed_formulas[sheet as usize][formula_index as usize];
-                let cell_ref = CellReferenceRC {
-                    sheet: worksheet.get_name(),
-                    row,
-                    column,
-                };
-                format!("={}", to_string(formula, &cell_ref))
-            })
-        }))
+        match worksheet.cell(row, column) {
+            Some(cell) => match cell.get_formula() {
+                Some(formula_index) => {
+                    let formula = &self
+                        .parsed_formulas
+                        .get(sheet as usize)
+                        .ok_or("missing sheet")?
+                        .get(formula_index as usize)
+                        .ok_or("missing formula")?;
+                    let cell_ref = CellReferenceRC {
+                        sheet: worksheet.get_name(),
+                        row,
+                        column,
+                    };
+                    Ok(Some(format!("={}", to_string(formula, &cell_ref))))
+                }
+                None => Ok(None),
+            },
+            None => Ok(None),
+        }
     }
 
     /// Updates the value of a cell with some text
@@ -1178,14 +1196,14 @@ impl Model {
     /// # Examples
     ///
     /// ```rust
-    /// # use ironcalc_base::model::Model;
+    /// # use ironcalc_base::Model;
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// let mut model = Model::new_empty("model", "en", "UTC")?;
     /// let (sheet, row, column) = (0, 1, 1);
-    /// model.set_user_input(sheet, row, column, "Hello!".to_string());
+    /// model.set_user_input(sheet, row, column, "Hello!".to_string())?;
     /// assert_eq!(model.get_cell_content(sheet, row, column)?, "Hello!".to_string());
     ///
-    /// model.update_cell_with_text(sheet, row, column, "Goodbye!");
+    /// model.update_cell_with_text(sheet, row, column, "Goodbye!")?;
     /// assert_eq!(model.get_cell_content(sheet, row, column)?, "Goodbye!".to_string());
     /// # Ok(())
     /// # }
@@ -1196,23 +1214,30 @@ impl Model {
     /// * [Model::update_cell_with_number()]
     /// * [Model::update_cell_with_bool()]
     /// * [Model::update_cell_with_formula()]
-    pub fn update_cell_with_text(&mut self, sheet: u32, row: i32, column: i32, value: &str) {
-        let style_index = self.get_cell_style_index(sheet, row, column);
+    pub fn update_cell_with_text(
+        &mut self,
+        sheet: u32,
+        row: i32,
+        column: i32,
+        value: &str,
+    ) -> Result<(), String> {
+        let style_index = self.get_cell_style_index(sheet, row, column)?;
         let new_style_index;
         if common::value_needs_quoting(value, &self.language) {
             new_style_index = self
                 .workbook
                 .styles
-                .get_style_with_quote_prefix(style_index);
+                .get_style_with_quote_prefix(style_index)?;
         } else if self.workbook.styles.style_is_quote_prefix(style_index) {
             new_style_index = self
                 .workbook
                 .styles
-                .get_style_without_quote_prefix(style_index);
+                .get_style_without_quote_prefix(style_index)?;
         } else {
             new_style_index = style_index;
         }
-        self.set_cell_with_string(sheet, row, column, value, new_style_index);
+
+        self.set_cell_with_string(sheet, row, column, value, new_style_index)
     }
 
     /// Updates the value of a cell with a boolean value
@@ -1221,14 +1246,14 @@ impl Model {
     /// # Examples
     ///
     /// ```rust
-    /// # use ironcalc_base::model::Model;
+    /// # use ironcalc_base::Model;
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// let mut model = Model::new_empty("model", "en", "UTC")?;
     /// let (sheet, row, column) = (0, 1, 1);
-    /// model.set_user_input(sheet, row, column, "TRUE".to_string());
+    /// model.set_user_input(sheet, row, column, "TRUE".to_string())?;
     /// assert_eq!(model.get_cell_content(sheet, row, column)?, "TRUE".to_string());
     ///
-    /// model.update_cell_with_bool(sheet, row, column, false);
+    /// model.update_cell_with_bool(sheet, row, column, false)?;
     /// assert_eq!(model.get_cell_content(sheet, row, column)?, "FALSE".to_string());
     /// # Ok(())
     /// # }
@@ -1239,17 +1264,22 @@ impl Model {
     /// * [Model::update_cell_with_number()]
     /// * [Model::update_cell_with_text()]
     /// * [Model::update_cell_with_formula()]
-    pub fn update_cell_with_bool(&mut self, sheet: u32, row: i32, column: i32, value: bool) {
-        let style_index = self.get_cell_style_index(sheet, row, column);
+    pub fn update_cell_with_bool(
+        &mut self,
+        sheet: u32,
+        row: i32,
+        column: i32,
+        value: bool,
+    ) -> Result<(), String> {
+        let style_index = self.get_cell_style_index(sheet, row, column)?;
         let new_style_index = if self.workbook.styles.style_is_quote_prefix(style_index) {
             self.workbook
                 .styles
-                .get_style_without_quote_prefix(style_index)
+                .get_style_without_quote_prefix(style_index)?
         } else {
             style_index
         };
-        let worksheet = &mut self.workbook.worksheets[sheet as usize];
-        worksheet.set_cell_with_boolean(row, column, value, new_style_index);
+        self.set_cell_with_boolean(sheet, row, column, value, new_style_index)
     }
 
     /// Updates the value of a cell with a number
@@ -1258,14 +1288,14 @@ impl Model {
     /// # Examples
     ///
     /// ```rust
-    /// # use ironcalc_base::model::Model;
+    /// # use ironcalc_base::Model;
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// let mut model = Model::new_empty("model", "en", "UTC")?;
     /// let (sheet, row, column) = (0, 1, 1);
-    /// model.set_user_input(sheet, row, column, "42".to_string());
+    /// model.set_user_input(sheet, row, column, "42".to_string())?;
     /// assert_eq!(model.get_cell_content(sheet, row, column)?, "42".to_string());
     ///
-    /// model.update_cell_with_number(sheet, row, column, 23.0);
+    /// model.update_cell_with_number(sheet, row, column, 23.0)?;
     /// assert_eq!(model.get_cell_content(sheet, row, column)?, "23".to_string());
     /// # Ok(())
     /// # }
@@ -1276,17 +1306,22 @@ impl Model {
     /// * [Model::update_cell_with_text()]
     /// * [Model::update_cell_with_bool()]
     /// * [Model::update_cell_with_formula()]
-    pub fn update_cell_with_number(&mut self, sheet: u32, row: i32, column: i32, value: f64) {
-        let style_index = self.get_cell_style_index(sheet, row, column);
+    pub fn update_cell_with_number(
+        &mut self,
+        sheet: u32,
+        row: i32,
+        column: i32,
+        value: f64,
+    ) -> Result<(), String> {
+        let style_index = self.get_cell_style_index(sheet, row, column)?;
         let new_style_index = if self.workbook.styles.style_is_quote_prefix(style_index) {
             self.workbook
                 .styles
-                .get_style_without_quote_prefix(style_index)
+                .get_style_without_quote_prefix(style_index)?
         } else {
             style_index
         };
-        let worksheet = &mut self.workbook.worksheets[sheet as usize];
-        worksheet.set_cell_with_number(row, column, value, new_style_index);
+        self.set_cell_with_number(sheet, row, column, value, new_style_index)
     }
 
     /// Updates the formula of given cell
@@ -1296,15 +1331,15 @@ impl Model {
     /// # Examples
     ///
     /// ```rust
-    /// # use ironcalc_base::model::Model;
+    /// # use ironcalc_base::Model;
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// let mut model = Model::new_empty("model", "en", "UTC")?;
     /// let (sheet, row, column) = (0, 1, 1);
-    /// model.set_user_input(sheet, row, column, "=A2*2".to_string());
+    /// model.set_user_input(sheet, row, column, "=A2*2".to_string())?;
     /// model.evaluate();
     /// assert_eq!(model.get_cell_content(sheet, row, column)?, "=A2*2".to_string());
     ///
-    /// model.update_cell_with_formula(sheet, row, column, "=A3*2".to_string());
+    /// model.update_cell_with_formula(sheet, row, column, "=A3*2".to_string())?;
     /// model.evaluate();
     /// assert_eq!(model.get_cell_content(sheet, row, column)?, "=A3*2".to_string());
     /// # Ok(())
@@ -1323,12 +1358,12 @@ impl Model {
         column: i32,
         formula: String,
     ) -> Result<(), String> {
-        let mut style_index = self.get_cell_style_index(sheet, row, column);
+        let mut style_index = self.get_cell_style_index(sheet, row, column)?;
         if self.workbook.styles.style_is_quote_prefix(style_index) {
             style_index = self
                 .workbook
                 .styles
-                .get_style_without_quote_prefix(style_index);
+                .get_style_without_quote_prefix(style_index)?;
         }
         let formula = formula
             .strip_prefix('=')
@@ -1348,7 +1383,7 @@ impl Model {
     /// # Examples
     ///
     /// ```rust
-    /// # use ironcalc_base::model::Model;
+    /// # use ironcalc_base::Model;
     /// # use ironcalc_base::cell::CellValue;
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// let mut model = Model::new_empty("model", "en", "UTC")?;
@@ -1358,7 +1393,7 @@ impl Model {
     /// model.set_user_input(0, 1, 2, "=SUM(A:A)".to_string());
     /// model.evaluate();
     /// assert_eq!(model.get_cell_value_by_index(0, 1, 2), Ok(CellValue::Number(215.0)));
-    /// assert_eq!(model.formatted_cell_value(0, 1, 2), Ok("215$".to_string()));
+    /// assert_eq!(model.get_formatted_cell_value(0, 1, 2), Ok("215$".to_string()));
     /// # Ok(())
     /// # }
     /// ```
@@ -1368,31 +1403,36 @@ impl Model {
     /// * [Model::update_cell_with_number()]
     /// * [Model::update_cell_with_bool()]
     /// * [Model::update_cell_with_text()]
-    pub fn set_user_input(&mut self, sheet: u32, row: i32, column: i32, value: String) {
+    pub fn set_user_input(
+        &mut self,
+        sheet: u32,
+        row: i32,
+        column: i32,
+        value: String,
+    ) -> Result<(), String> {
         // If value starts with "'" then we force the style to be quote_prefix
-        let style_index = self.get_cell_style_index(sheet, row, column);
+        let style_index = self.get_cell_style_index(sheet, row, column)?;
         if let Some(new_value) = value.strip_prefix('\'') {
             // First check if it needs quoting
             let new_style = if common::value_needs_quoting(new_value, &self.language) {
                 self.workbook
                     .styles
-                    .get_style_with_quote_prefix(style_index)
+                    .get_style_with_quote_prefix(style_index)?
             } else {
                 style_index
             };
-            self.set_cell_with_string(sheet, row, column, new_value, new_style);
+            self.set_cell_with_string(sheet, row, column, new_value, new_style)?;
         } else {
             let mut new_style_index = style_index;
             if self.workbook.styles.style_is_quote_prefix(style_index) {
                 new_style_index = self
                     .workbook
                     .styles
-                    .get_style_without_quote_prefix(style_index);
+                    .get_style_without_quote_prefix(style_index)?;
             }
             if let Some(formula) = value.strip_prefix('=') {
-                let formula_index = self
-                    .set_cell_with_formula(sheet, row, column, formula, new_style_index)
-                    .expect("could not set the cell formula");
+                let formula_index =
+                    self.set_cell_with_formula(sheet, row, column, formula, new_style_index)?;
                 // Update the style if needed
                 let cell = CellReferenceIndex { sheet, row, column };
                 let parsed_formula = &self.parsed_formulas[sheet as usize][formula_index as usize];
@@ -1400,15 +1440,11 @@ impl Model {
                     let new_style_index = self
                         .workbook
                         .styles
-                        .get_style_with_format(new_style_index, &units.get_num_fmt());
-                    let style = self.workbook.styles.get_style(new_style_index);
-                    self.set_cell_style(sheet, row, column, &style)
-                        .expect("Failed setting the style");
+                        .get_style_with_format(new_style_index, &units.get_num_fmt())?;
+                    let style = self.workbook.styles.get_style(new_style_index)?;
+                    self.set_cell_style(sheet, row, column, &style)?
                 }
             } else {
-                let worksheets = &mut self.workbook.worksheets;
-                let worksheet = &mut worksheets[sheet as usize];
-
                 // The list of currencies is '$', '€' and the local currency
                 let mut currencies = vec!["$", "€"];
                 let currency = &self.locale.currency.symbol;
@@ -1421,35 +1457,39 @@ impl Model {
                         // Should not apply the format in the following cases:
                         // - we assign a date to already date-formatted cell
                         let should_apply_format = !(is_likely_date_number_format(
-                            &self.workbook.styles.get_style(new_style_index).num_fmt,
+                            &self.workbook.styles.get_style(new_style_index)?.num_fmt,
                         ) && is_likely_date_number_format(&num_fmt));
                         if should_apply_format {
                             new_style_index = self
                                 .workbook
                                 .styles
-                                .get_style_with_format(new_style_index, &num_fmt);
+                                .get_style_with_format(new_style_index, &num_fmt)?;
                         }
                     }
-                    worksheet.set_cell_with_number(row, column, v, new_style_index);
-                    return;
+                    let worksheet = self.workbook.worksheet_mut(sheet)?;
+                    worksheet.set_cell_with_number(row, column, v, new_style_index)?;
+                    return Ok(());
                 }
                 // We try to parse as boolean
                 if let Ok(v) = value.to_lowercase().parse::<bool>() {
-                    worksheet.set_cell_with_boolean(row, column, v, new_style_index);
-                    return;
+                    let worksheet = self.workbook.worksheet_mut(sheet)?;
+                    worksheet.set_cell_with_boolean(row, column, v, new_style_index)?;
+                    return Ok(());
                 }
                 // Check is it is error value
                 let upper = value.to_uppercase();
+                let worksheet = self.workbook.worksheet_mut(sheet)?;
                 match get_error_by_name(&upper, &self.language) {
                     Some(error) => {
-                        worksheet.set_cell_with_error(row, column, error, new_style_index);
+                        worksheet.set_cell_with_error(row, column, error, new_style_index)?;
                     }
                     None => {
-                        self.set_cell_with_string(sheet, row, column, &value, new_style_index);
+                        self.set_cell_with_string(sheet, row, column, &value, new_style_index)?;
                     }
                 }
             }
         }
+        Ok(())
     }
 
     fn set_cell_with_formula(
@@ -1490,24 +1530,66 @@ impl Model {
             self.parsed_formulas[sheet as usize].push(parsed_formula);
             formula_index = (shared_formulas.len() as i32) - 1;
         }
-        worksheet.set_cell_with_formula(row, column, formula_index, style);
+        worksheet.set_cell_with_formula(row, column, formula_index, style)?;
         Ok(formula_index)
     }
 
-    fn set_cell_with_string(&mut self, sheet: u32, row: i32, column: i32, value: &str, style: i32) {
-        let worksheets = &mut self.workbook.worksheets;
-        let worksheet = &mut worksheets[sheet as usize];
+    fn set_cell_with_string(
+        &mut self,
+        sheet: u32,
+        row: i32,
+        column: i32,
+        value: &str,
+        style: i32,
+    ) -> Result<(), String> {
         match self.shared_strings.get(value) {
             Some(string_index) => {
-                worksheet.set_cell_with_string(row, column, *string_index as i32, style);
+                self.workbook.worksheet_mut(sheet)?.set_cell_with_string(
+                    row,
+                    column,
+                    *string_index as i32,
+                    style,
+                )?;
             }
             None => {
                 let string_index = self.workbook.shared_strings.len();
                 self.workbook.shared_strings.push(value.to_string());
                 self.shared_strings.insert(value.to_string(), string_index);
-                worksheet.set_cell_with_string(row, column, string_index as i32, style);
+                self.workbook.worksheet_mut(sheet)?.set_cell_with_string(
+                    row,
+                    column,
+                    string_index as i32,
+                    style,
+                )?;
             }
         }
+        Ok(())
+    }
+
+    fn set_cell_with_boolean(
+        &mut self,
+        sheet: u32,
+        row: i32,
+        column: i32,
+        value: bool,
+        style: i32,
+    ) -> Result<(), String> {
+        self.workbook
+            .worksheet_mut(sheet)?
+            .set_cell_with_boolean(row, column, value, style)
+    }
+
+    fn set_cell_with_number(
+        &mut self,
+        sheet: u32,
+        row: i32,
+        column: i32,
+        value: f64,
+        style: i32,
+    ) -> Result<(), String> {
+        self.workbook
+            .worksheet_mut(sheet)?
+            .set_cell_with_number(row, column, value, style)
     }
 
     /// Gets the Excel Value (Bool, Number, String) of a cell
@@ -1529,7 +1611,7 @@ impl Model {
     /// Returns the cell value for (`sheet`, `row`, `column`)
     ///
     /// See also:
-    /// * [Model::formatted_cell_value()]
+    /// * [Model::get_formatted_cell_value()]
     pub fn get_cell_value_by_index(
         &self,
         sheet_index: u32,
@@ -1555,35 +1637,42 @@ impl Model {
     /// # Examples
     ///
     /// ```rust
-    /// # use ironcalc_base::model::Model;
+    /// # use ironcalc_base::Model;
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// let mut model = Model::new_empty("model", "en", "UTC")?;
     /// let (sheet, row, column) = (0, 1, 1);
     /// model.set_user_input(sheet, row, column, "=1/3".to_string());
     /// model.evaluate();
-    /// let result = model.formatted_cell_value(sheet, row, column)?;
+    /// let result = model.get_formatted_cell_value(sheet, row, column)?;
     /// assert_eq!(result, "0.333333333".to_string());
     /// # Ok(())
     /// # }
     /// ```
-    pub fn formatted_cell_value(
+    pub fn get_formatted_cell_value(
         &self,
         sheet_index: u32,
         row: i32,
         column: i32,
     ) -> Result<String, String> {
-        let format = self.get_style_for_cell(sheet_index, row, column).num_fmt;
-        let cell = self
-            .workbook
-            .worksheet(sheet_index)?
-            .cell(row, column)
-            .cloned()
-            .unwrap_or_default();
-        let formatted_value =
-            cell.formatted_value(&self.workbook.shared_strings, &self.language, |value| {
-                format_number(value, &format, &self.locale).text
-            });
-        Ok(formatted_value)
+        match self.workbook.worksheet(sheet_index)?.cell(row, column) {
+            Some(cell) => {
+                let format = self.get_style_for_cell(sheet_index, row, column)?.num_fmt;
+                let formatted_value =
+                    cell.formatted_value(&self.workbook.shared_strings, &self.language, |value| {
+                        format_number(value, &format, &self.locale).text
+                    });
+                Ok(formatted_value)
+            }
+            None => Ok("".to_string()),
+        }
+    }
+
+    /// Return the typeof a cell
+    pub fn get_cell_type(&self, sheet: u32, row: i32, column: i32) -> Result<CellType, String> {
+        Ok(match self.workbook.worksheet(sheet)?.cell(row, column) {
+            Some(c) => c.get_type(),
+            None => CellType::Number,
+        })
     }
 
     /// Returns a string with the cell content. If there is a formula returns the formula
@@ -1647,15 +1736,53 @@ impl Model {
         }
     }
 
-    /// Sets cell to empty. Can be used to delete value without affecting style.
-    pub fn set_cell_empty(&mut self, sheet: u32, row: i32, column: i32) -> Result<(), String> {
-        let worksheet = self.workbook.worksheet_mut(sheet)?;
-        worksheet.set_cell_empty(row, column);
+    /// Removes the content of the cell but leaves the style.
+    ///
+    /// See also:
+    /// * [Model::cell_clear_all()]
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// # use ironcalc_base::Model;
+    /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
+    /// let mut model = Model::new_empty("model", "en", "UTC")?;
+    /// let (sheet, row, column) = (0, 1, 1);
+    /// model.set_user_input(sheet, row, column, "100$".to_string());
+    /// model.cell_clear_contents(sheet, row, column);
+    /// model.set_user_input(sheet, row, column, "10".to_string());
+    /// let result = model.get_formatted_cell_value(sheet, row, column)?;
+    /// assert_eq!(result, "10$".to_string());
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn cell_clear_contents(&mut self, sheet: u32, row: i32, column: i32) -> Result<(), String> {
+        self.workbook
+            .worksheet_mut(sheet)?
+            .cell_clear_contents(row, column)?;
         Ok(())
     }
 
-    /// Deletes a cell by removing it from worksheet data.
-    pub fn delete_cell(&mut self, sheet: u32, row: i32, column: i32) -> Result<(), String> {
+    /// Deletes a cell by removing it from worksheet data. All content and style is removed.
+    ///
+    /// See also:
+    /// * [Model::cell_clear_contents()]
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// # use ironcalc_base::Model;
+    /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
+    /// let mut model = Model::new_empty("model", "en", "UTC")?;
+    /// let (sheet, row, column) = (0, 1, 1);
+    /// model.set_user_input(sheet, row, column, "100$".to_string());
+    /// model.cell_clear_all(sheet, row, column);
+    /// model.set_user_input(sheet, row, column, "10".to_string());
+    /// let result = model.get_formatted_cell_value(sheet, row, column)?;
+    /// assert_eq!(result, "10".to_string());
+    /// # Ok(())
+    /// # }
+    pub fn cell_clear_all(&mut self, sheet: u32, row: i32, column: i32) -> Result<(), String> {
         let worksheet = self.workbook.worksheet_mut(sheet)?;
 
         let sheet_data = &mut worksheet.sheet_data;
@@ -1667,59 +1794,66 @@ impl Model {
     }
 
     /// Returns the style index for cell (`sheet`, `row`, `column`)
-    pub fn get_cell_style_index(&self, sheet: u32, row: i32, column: i32) -> i32 {
+    pub fn get_cell_style_index(&self, sheet: u32, row: i32, column: i32) -> Result<i32, String> {
         // First check the cell, then row, the column
-        let cell = self
-            .workbook
-            .worksheet(sheet)
-            .expect("Invalid sheet")
-            .cell(row, column);
+        let cell = self.workbook.worksheet(sheet)?.cell(row, column);
+
         match cell {
-            Some(cell) => cell.get_style(),
+            Some(cell) => Ok(cell.get_style()),
             None => {
-                let rows = &self.workbook.worksheets[sheet as usize].rows;
+                let rows = &self.workbook.worksheet(sheet)?.rows;
                 for r in rows {
                     if r.r == row {
                         if r.custom_format {
-                            return r.s;
-                        } else {
-                            break;
+                            return Ok(r.s);
                         }
+                        break;
                     }
                 }
-                let cols = &self.workbook.worksheets[sheet as usize].cols;
+                let cols = &self.workbook.worksheet(sheet)?.cols;
                 for c in cols.iter() {
                     let min = c.min;
                     let max = c.max;
                     if column >= min && column <= max {
-                        return c.style.unwrap_or(0);
+                        return Ok(c.style.unwrap_or(0));
                     }
                 }
-                0
+                Ok(0)
             }
         }
     }
 
     /// Returns the style for cell (`sheet`, `row`, `column`)
-    pub fn get_style_for_cell(&self, sheet: u32, row: i32, column: i32) -> Style {
-        self.workbook
-            .styles
-            .get_style(self.get_cell_style_index(sheet, row, column))
+    pub fn get_style_for_cell(&self, sheet: u32, row: i32, column: i32) -> Result<Style, String> {
+        let style_index = self.get_cell_style_index(sheet, row, column)?;
+        let style = self.workbook.styles.get_style(style_index)?;
+        Ok(style)
     }
 
-    /// Returns a JSON string of the workbook
-    pub fn to_json_str(&self) -> String {
-        match serde_json::to_string(&self.workbook) {
-            Ok(s) => s,
-            Err(_) => {
-                // TODO, is this branch possible at all?
-                json!({"error": "Error stringifying workbook"}).to_string()
-            }
-        }
+    /// Returns an internal binary representation of the workbook
+    ///
+    /// See also:
+    /// * [Model::from_bytes]
+    pub fn to_bytes(&self) -> Vec<u8> {
+        bitcode::encode(&self.workbook)
+    }
+
+    /// Returns data about the worksheets
+    pub fn get_worksheets_properties(&self) -> Vec<SheetProperties> {
+        self.workbook
+            .worksheets
+            .iter()
+            .map(|worksheet| SheetProperties {
+                name: worksheet.get_name(),
+                state: worksheet.state.to_string(),
+                color: worksheet.color.clone(),
+                sheet_id: worksheet.sheet_id,
+            })
+            .collect()
     }
 
     /// Returns markup representation of the given `sheet`.
-    pub fn sheet_markup(&self, sheet: u32) -> Result<String, String> {
+    pub fn get_sheet_markup(&self, sheet: u32) -> Result<String, String> {
         let worksheet = self.workbook.worksheet(sheet)?;
         let dimension = worksheet.dimension();
 
@@ -1729,11 +1863,11 @@ impl Model {
             let mut row_markup: Vec<String> = Vec::new();
 
             for column in 1..(dimension.max_column + 1) {
-                let mut cell_markup = match self.cell_formula(sheet, row, column)? {
+                let mut cell_markup = match self.get_cell_formula(sheet, row, column)? {
                     Some(formula) => formula,
-                    None => self.formatted_cell_value(sheet, row, column)?,
+                    None => self.get_formatted_cell_value(sheet, row, column)?,
                 };
-                let style = self.get_style_for_cell(sheet, row, column);
+                let style = self.get_style_for_cell(sheet, row, column)?;
                 if style.font.b {
                     cell_markup = format!("**{cell_markup}**")
                 }
@@ -1770,7 +1904,7 @@ impl Model {
     }
 
     /// Returns the number of frozen rows in `sheet`
-    pub fn get_frozen_rows(&self, sheet: u32) -> Result<i32, String> {
+    pub fn get_frozen_rows_count(&self, sheet: u32) -> Result<i32, String> {
         if let Some(worksheet) = self.workbook.worksheets.get(sheet as usize) {
             Ok(worksheet.frozen_rows)
         } else {
@@ -1779,7 +1913,7 @@ impl Model {
     }
 
     /// Return the number of frozen columns in `sheet`
-    pub fn get_frozen_columns(&self, sheet: u32) -> Result<i32, String> {
+    pub fn get_frozen_columns_count(&self, sheet: u32) -> Result<i32, String> {
         if let Some(worksheet) = self.workbook.worksheets.get(sheet as usize) {
             Ok(worksheet.frozen_columns)
         } else {
@@ -1820,6 +1954,34 @@ impl Model {
             Err("Invalid sheet".to_string())
         }
     }
+
+    /// Returns the width of a column
+    #[inline]
+    pub fn get_column_width(&self, sheet: u32, column: i32) -> Result<f64, String> {
+        self.workbook.worksheet(sheet)?.get_column_width(column)
+    }
+
+    /// Sets the width of a column
+    #[inline]
+    pub fn set_column_width(&mut self, sheet: u32, column: i32, width: f64) -> Result<(), String> {
+        self.workbook
+            .worksheet_mut(sheet)?
+            .set_column_width(column, width)
+    }
+
+    /// Returns the height of a row
+    #[inline]
+    pub fn get_row_height(&self, sheet: u32, row: i32) -> Result<f64, String> {
+        self.workbook.worksheet(sheet)?.row_height(row)
+    }
+
+    /// Sets the height of a row
+    #[inline]
+    pub fn set_row_height(&mut self, sheet: u32, column: i32, height: f64) -> Result<(), String> {
+        self.workbook
+            .worksheet_mut(sheet)?
+            .set_row_height(column, height)
+    }
 }
 
 #[cfg(test)]

base/src/new_empty.rs

@@ -1,19 +1,24 @@
-use chrono::NaiveDateTime;
+use chrono::DateTime;
 
 use std::collections::HashMap;
 
 use crate::{
     calc_result::Range,
+    constants::{DEFAULT_WINDOW_HEIGH, DEFAULT_WINDOW_WIDTH},
     expressions::{
         lexer::LexerMode,
-        parser::stringify::{rename_sheet_in_node, to_rc_format},
-        parser::Parser,
+        parser::{
+            stringify::{rename_sheet_in_node, to_rc_format},
+            Parser,
+        },
         types::CellReferenceRC,
     },
     language::get_language,
     locale::get_locale,
     model::{get_milliseconds_since_epoch, Model, ParsedDefinedName},
-    types::{Metadata, SheetState, Workbook, WorkbookSettings, Worksheet},
+    types::{
+        Metadata, SheetState, Workbook, WorkbookSettings, WorkbookView, Worksheet, WorksheetView,
+    },
     utils::ParsedReference,
 };
 
@@ -33,7 +38,20 @@ fn is_valid_sheet_name(name: &str) -> bool {
 
 impl Model {
     /// Creates a new worksheet. Note that it does not check if the name or the sheet_id exists
-    fn new_empty_worksheet(name: &str, sheet_id: u32) -> Worksheet {
+    fn new_empty_worksheet(name: &str, sheet_id: u32, view_ids: &[&u32]) -> Worksheet {
+        let mut views = HashMap::new();
+        for id in view_ids {
+            views.insert(
+                **id,
+                WorksheetView {
+                    row: 1,
+                    column: 1,
+                    range: [1, 1, 1, 1],
+                    top_row: 1,
+                    left_column: 1,
+                },
+            );
+        }
         Worksheet {
             cols: vec![],
             rows: vec![],
@@ -48,6 +66,8 @@ impl Model {
             color: Default::default(),
             frozen_columns: 0,
             frozen_rows: 0,
+            show_grid_lines: true,
+            views,
         }
     }
 
@@ -122,8 +142,8 @@ impl Model {
         self.parsed_defined_names = parsed_defined_names;
     }
 
-    // Reparses all formulas and defined names
-    fn reset_parsed_structures(&mut self) {
+    /// Reparses all formulas and defined names
+    pub(crate) fn reset_parsed_structures(&mut self) {
         self.parser
             .set_worksheets(self.workbook.get_worksheet_names());
         self.parsed_formulas = vec![];
@@ -134,10 +154,10 @@ impl Model {
     }
 
     /// Adds a sheet with a automatically generated name
-    pub fn new_sheet(&mut self) {
+    pub fn new_sheet(&mut self) -> (String, u32) {
         // First we find a name
 
-        // TODO: When/if we support i18n the name could depend on the locale
+        // TODO: The name should depend on the locale
         let base_name = "Sheet";
         let base_name_uppercase = base_name.to_uppercase();
         let mut index = 1;
@@ -153,9 +173,11 @@ impl Model {
         let sheet_name = format!("{}{}", base_name, index);
         // Now we need a sheet_id
         let sheet_id = self.get_new_sheet_id();
-        let worksheet = Model::new_empty_worksheet(&sheet_name, sheet_id);
+        let view_ids: Vec<&u32> = self.workbook.views.keys().collect();
+        let worksheet = Model::new_empty_worksheet(&sheet_name, sheet_id, &view_ids);
         self.workbook.worksheets.push(worksheet);
         self.reset_parsed_structures();
+        (sheet_name, self.workbook.worksheets.len() as u32 - 1)
     }
 
     /// Inserts a sheet with a particular index
@@ -183,7 +205,8 @@ impl Model {
             Some(id) => id,
             None => self.get_new_sheet_id(),
         };
-        let worksheet = Model::new_empty_worksheet(sheet_name, sheet_id);
+        let view_ids: Vec<&u32> = self.workbook.views.keys().collect();
+        let worksheet = Model::new_empty_worksheet(sheet_name, sheet_id, &view_ids);
         if sheet_index as usize > self.workbook.worksheets.len() {
             return Err("Sheet index out of range".to_string());
         }
@@ -223,10 +246,10 @@ impl Model {
         new_name: &str,
     ) -> Result<(), String> {
         if !is_valid_sheet_name(new_name) {
-            return Err(format!("Invalid name for a sheet: '{}'", new_name));
+            return Err(format!("Invalid name for a sheet: '{}'.", new_name));
         }
         if self.get_sheet_index_by_name(new_name).is_some() {
-            return Err(format!("Sheet already exists: '{}'", new_name));
+            return Err(format!("Sheet already exists: '{}'.", new_name));
         }
         let worksheets = &self.workbook.worksheets;
         let sheet_count = worksheets.len() as u32;
@@ -270,7 +293,7 @@ impl Model {
         if sheet_count == 1 {
             return Err("Cannot delete only sheet".to_string());
         };
-        if sheet_index > sheet_count {
+        if sheet_index >= sheet_count {
             return Err("Sheet index too large".to_string());
         }
         self.workbook.worksheets.remove(sheet_index as usize);
@@ -323,18 +346,28 @@ impl Model {
 
         let milliseconds = get_milliseconds_since_epoch();
         let seconds = milliseconds / 1000;
-        let dt = match NaiveDateTime::from_timestamp_opt(seconds, 0) {
+        let dt = match DateTime::from_timestamp(seconds, 0) {
             Some(s) => s,
             None => return Err(format!("Invalid timestamp: {}", milliseconds)),
         };
         // "2020-08-06T21:20:53Z
         let now = dt.format("%Y-%m-%dT%H:%M:%SZ").to_string();
 
+        let mut views = HashMap::new();
+        views.insert(
+            0,
+            WorkbookView {
+                sheet: 0,
+                window_width: DEFAULT_WINDOW_WIDTH,
+                window_height: DEFAULT_WINDOW_HEIGH,
+            },
+        );
+
         // String versions of the locale are added here to simplify the serialize/deserialize logic
         let workbook = Workbook {
             shared_strings: vec![],
             defined_names: vec![],
-            worksheets: vec![Model::new_empty_worksheet("Sheet1", 1)],
+            worksheets: vec![Model::new_empty_worksheet("Sheet1", 1, &[&0])],
             styles: Default::default(),
             name: name.to_string(),
             settings: WorkbookSettings {
@@ -350,6 +383,7 @@ impl Model {
                 last_modified: now,
             },
             tables: HashMap::new(),
+            views,
         };
         let parsed_formulas = Vec::new();
         let worksheets = &workbook.worksheets;
@@ -370,6 +404,7 @@ impl Model {
             locale,
             language,
             tz,
+            view_id: 0,
         };
         model.parse_formulas();
         Ok(model)

base/src/styles.rs

@@ -161,26 +161,29 @@ impl Styles {
 
     pub fn create_named_style(&mut self, style_name: &str, style: &Style) -> Result<(), String> {
         let style_index = self.create_new_style(style);
-        self.add_named_cell_style(style_name, style_index)?;
-        Ok(())
+        self.add_named_cell_style(style_name, style_index)
     }
 
-    pub(crate) fn get_style_with_quote_prefix(&mut self, index: i32) -> i32 {
-        let mut style = self.get_style(index);
+    pub(crate) fn get_style_with_quote_prefix(&mut self, index: i32) -> Result<i32, String> {
+        let mut style = self.get_style(index)?;
         style.quote_prefix = true;
-        self.get_style_index_or_create(&style)
+        Ok(self.get_style_index_or_create(&style))
     }
 
-    pub(crate) fn get_style_with_format(&mut self, index: i32, num_fmt: &str) -> i32 {
-        let mut style = self.get_style(index);
+    pub(crate) fn get_style_with_format(
+        &mut self,
+        index: i32,
+        num_fmt: &str,
+    ) -> Result<i32, String> {
+        let mut style = self.get_style(index)?;
         style.num_fmt = num_fmt.to_string();
-        self.get_style_index_or_create(&style)
+        Ok(self.get_style_index_or_create(&style))
     }
 
-    pub(crate) fn get_style_without_quote_prefix(&mut self, index: i32) -> i32 {
-        let mut style = self.get_style(index);
+    pub(crate) fn get_style_without_quote_prefix(&mut self, index: i32) -> Result<i32, String> {
+        let mut style = self.get_style(index)?;
         style.quote_prefix = false;
-        self.get_style_index_or_create(&style)
+        Ok(self.get_style_index_or_create(&style))
     }
 
     pub(crate) fn style_is_quote_prefix(&self, index: i32) -> bool {
@@ -188,9 +191,11 @@ impl Styles {
         cell_xf.quote_prefix
     }
 
-    pub(crate) fn get_style(&self, index: i32) -> Style {
-        let cell_xf = &self.cell_xfs[index as usize];
-
+    pub(crate) fn get_style(&self, index: i32) -> Result<Style, String> {
+        let cell_xf = &self
+            .cell_xfs
+            .get(index as usize)
+            .ok_or("Invalid index provided".to_string())?;
         let border_id = cell_xf.border_id as usize;
         let fill_id = cell_xf.fill_id as usize;
         let font_id = cell_xf.font_id as usize;
@@ -198,14 +203,14 @@ impl Styles {
         let quote_prefix = cell_xf.quote_prefix;
         let alignment = cell_xf.alignment.clone();
 
-        Style {
+        Ok(Style {
             alignment,
             num_fmt: get_num_fmt(num_fmt_id, &self.num_fmts),
             fill: self.fills[fill_id].clone(),
             font: self.fonts[font_id].clone(),
             border: self.borders[border_id].clone(),
             quote_prefix,
-        }
+        })
     }
 }
 
@@ -221,8 +226,7 @@ impl Model {
         let style_index = self.workbook.styles.get_style_index_or_create(style);
         self.workbook
             .worksheet_mut(sheet)?
-            .set_cell_style(row, column, style_index);
-        Ok(())
+            .set_cell_style(row, column, style_index)
     }
 
     pub fn copy_cell_style(
@@ -237,9 +241,7 @@ impl Model {
 
         self.workbook
             .worksheet_mut(destination_cell.0)?
-            .set_cell_style(destination_cell.1, destination_cell.2, source_style_index);
-
-        Ok(())
+            .set_cell_style(destination_cell.1, destination_cell.2, source_style_index)
     }
 
     /// Sets the style "style_name" in cell
@@ -253,8 +255,7 @@ impl Model {
         let style_index = self.workbook.styles.get_style_index_by_name(style_name)?;
         self.workbook
             .worksheet_mut(sheet)?
-            .set_cell_style(row, column, style_index);
-        Ok(())
+            .set_cell_style(row, column, style_index)
     }
 
     pub fn set_sheet_style(&mut self, sheet: u32, style_name: &str) -> Result<(), String> {

base/src/test/engineering/test_complex.rs

@@ -76,10 +76,16 @@ fn fn_imconjugate() {
 fn fn_imcos() {
     let mut model = new_empty_model();
     model._set("A1", r#"=IMCOS("4+3i")"#);
+    // In macos non intel this is "-6.58066304055116+7.58155274274655i"
+    model._set("A2", r#"=COMPLEX(-6.58066304055116, 7.58155274274654)"#);
+    model._set("A3", r#"=IMABS(IMSUB(A1, A2)) < G1"#);
+
+    // small number
+    model._set("G1", "0.0000001");
 
     model.evaluate();
 
-    assert_eq!(model._get_text("A1"), "-6.58066304055116+7.58155274274654i");
+    assert_eq!(model._get_text("A3"), "TRUE");
 }
 
 #[test]

base/src/test/mod.rs

@@ -1,6 +1,7 @@
 mod test_actions;
 mod test_binary_search;
 mod test_cell;
+mod test_cell_clear_contents;
 mod test_circular_references;
 mod test_column_width;
 mod test_criteria;
@@ -28,9 +29,8 @@ mod test_frozen_rows_columns;
 mod test_general;
 mod test_math;
 mod test_metadata;
-mod test_model_delete_cell;
+mod test_model_cell_clear_all;
 mod test_model_is_empty_cell;
-mod test_model_set_cell_empty;
 mod test_move_formula;
 mod test_quote_prefix;
 mod test_set_user_input;
@@ -52,5 +52,7 @@ mod test_fn_type;
 mod test_frozen_rows_and_columns;
 mod test_get_cell_content;
 mod test_percentage;
+mod test_set_functions_error_handling;
 mod test_today;
-mod test_gc;
+mod test_types;
+mod user_model;

base/src/test/test_actions.rs

@@ -3,6 +3,7 @@
 use crate::constants::LAST_COLUMN;
 use crate::model::Model;
 use crate::test::util::new_empty_model;
+use crate::types::Col;
 
 #[test]
 fn test_insert_columns() {
@@ -195,6 +196,250 @@ fn test_delete_columns() {
     assert_eq!(model._get_formula("A3"), *"=SUM(#REF!:K4)");
 }
 
+#[test]
+fn test_delete_column_width() {
+    let mut model = new_empty_model();
+    let (sheet, column) = (0, 5);
+    let normal_width = model.get_column_width(sheet, column).unwrap();
+    // Set the width of one column to 5 times the normal width
+    assert!(model
+        .set_column_width(sheet, column, normal_width * 5.0)
+        .is_ok());
+
+    // delete it
+    assert!(model.delete_columns(sheet, column, 1).is_ok());
+
+    // all the columns around have the expected width
+    assert_eq!(
+        model.get_column_width(sheet, column - 1).unwrap(),
+        normal_width
+    );
+    assert_eq!(model.get_column_width(sheet, column).unwrap(), normal_width);
+    assert_eq!(
+        model.get_column_width(sheet, column + 1).unwrap(),
+        normal_width
+    );
+}
+
+#[test]
+// We set the style of columns 4 to 7 and delete column 4
+// We check that columns 4 to 6 have the new style
+fn test_delete_first_column_width() {
+    let mut model = new_empty_model();
+    model.workbook.worksheets[0].cols = vec![Col {
+        min: 4,
+        max: 7,
+        width: 300.0,
+        custom_width: true,
+        style: None,
+    }];
+    let (sheet, column) = (0, 4);
+    assert!(model.delete_columns(sheet, column, 1).is_ok());
+    let cols = &model.workbook.worksheets[0].cols;
+    assert_eq!(cols.len(), 1);
+    assert_eq!(
+        cols[0],
+        Col {
+            min: 4,
+            max: 6,
+            width: 300.0,
+            custom_width: true,
+            style: None
+        }
+    );
+}
+
+#[test]
+// Delete the last column in the range
+fn test_delete_last_column_width() {
+    let mut model = new_empty_model();
+    model.workbook.worksheets[0].cols = vec![Col {
+        min: 4,
+        max: 7,
+        width: 300.0,
+        custom_width: true,
+        style: None,
+    }];
+    let (sheet, column) = (0, 7);
+    assert!(model.delete_columns(sheet, column, 1).is_ok());
+    let cols = &model.workbook.worksheets[0].cols;
+    assert_eq!(cols.len(), 1);
+    assert_eq!(
+        cols[0],
+        Col {
+            min: 4,
+            max: 6,
+            width: 300.0,
+            custom_width: true,
+            style: None
+        }
+    );
+}
+
+#[test]
+// Deletes columns at the end
+fn test_delete_last_few_columns_width() {
+    let mut model = new_empty_model();
+    model.workbook.worksheets[0].cols = vec![Col {
+        min: 4,
+        max: 17,
+        width: 300.0,
+        custom_width: true,
+        style: None,
+    }];
+    let (sheet, column) = (0, 13);
+    assert!(model.delete_columns(sheet, column, 10).is_ok());
+    let cols = &model.workbook.worksheets[0].cols;
+    assert_eq!(cols.len(), 1);
+    assert_eq!(
+        cols[0],
+        Col {
+            min: 4,
+            max: 12,
+            width: 300.0,
+            custom_width: true,
+            style: None
+        }
+    );
+}
+
+#[test]
+fn test_delete_columns_non_overlapping_left() {
+    let mut model = new_empty_model();
+    model.workbook.worksheets[0].cols = vec![Col {
+        min: 10,
+        max: 17,
+        width: 300.0,
+        custom_width: true,
+        style: None,
+    }];
+    let (sheet, column) = (0, 3);
+    assert!(model.delete_columns(sheet, column, 4).is_ok());
+    let cols = &model.workbook.worksheets[0].cols;
+    assert_eq!(cols.len(), 1);
+    assert_eq!(
+        cols[0],
+        Col {
+            min: 6,
+            max: 13,
+            width: 300.0,
+            custom_width: true,
+            style: None
+        }
+    );
+}
+
+#[test]
+fn test_delete_columns_overlapping_left() {
+    let mut model = new_empty_model();
+    model.workbook.worksheets[0].cols = vec![Col {
+        min: 10,
+        max: 20,
+        width: 300.0,
+        custom_width: true,
+        style: None,
+    }];
+    let (sheet, column) = (0, 8);
+    assert!(model.delete_columns(sheet, column, 4).is_ok());
+    let cols = &model.workbook.worksheets[0].cols;
+    assert_eq!(cols.len(), 1);
+    assert_eq!(
+        cols[0],
+        Col {
+            min: 8,
+            max: 16,
+            width: 300.0,
+            custom_width: true,
+            style: None
+        }
+    );
+}
+
+#[test]
+fn test_delete_columns_non_overlapping_right() {
+    let mut model = new_empty_model();
+    model.workbook.worksheets[0].cols = vec![Col {
+        min: 10,
+        max: 17,
+        width: 300.0,
+        custom_width: true,
+        style: None,
+    }];
+    let (sheet, column) = (0, 23);
+    assert!(model.delete_columns(sheet, column, 4).is_ok());
+    let cols = &model.workbook.worksheets[0].cols;
+    assert_eq!(cols.len(), 1);
+    assert_eq!(
+        cols[0],
+        Col {
+            min: 10,
+            max: 17,
+            width: 300.0,
+            custom_width: true,
+            style: None
+        }
+    );
+}
+
+#[test]
+// deletes some columns in the middle of the range
+fn test_delete_middle_column_width() {
+    let mut model = new_empty_model();
+    // styled columns [4, 17]
+    model.workbook.worksheets[0].cols = vec![Col {
+        min: 4,
+        max: 17,
+        width: 300.0,
+        custom_width: true,
+        style: None,
+    }];
+
+    // deletes columns 10, 11, 12
+    let (sheet, column) = (0, 10);
+    assert!(model.delete_columns(sheet, column, 3).is_ok());
+    let cols = &model.workbook.worksheets[0].cols;
+    assert_eq!(cols.len(), 1);
+    assert_eq!(
+        cols[0],
+        Col {
+            min: 4,
+            max: 14,
+            width: 300.0,
+            custom_width: true,
+            style: None
+        }
+    );
+}
+
+#[test]
+// the range is inside the deleted columns
+fn delete_range_in_columns() {
+    let mut model = new_empty_model();
+    // styled columns [6, 10]
+    model.workbook.worksheets[0].cols = vec![Col {
+        min: 6,
+        max: 10,
+        width: 300.0,
+        custom_width: true,
+        style: None,
+    }];
+
+    // deletes columns [4, 17]
+    let (sheet, column) = (0, 4);
+    assert!(model.delete_columns(sheet, column, 8).is_ok());
+    let cols = &model.workbook.worksheets[0].cols;
+    assert_eq!(cols.len(), 0);
+}
+
+#[test]
+fn test_delete_columns_error() {
+    let mut model = new_empty_model();
+    let (sheet, column) = (0, 5);
+    assert!(model.delete_columns(sheet, column, -1).is_err());
+    assert!(model.delete_columns(sheet, column, 0).is_err());
+    assert!(model.delete_columns(sheet, column, 1).is_ok());
+}
+
 #[test]
 fn test_delete_rows() {
     let mut model = new_empty_model();

base/src/test/test_cell_clear_contents.rs

@@ -2,25 +2,25 @@
 use crate::test::util::new_empty_model;
 
 #[test]
-fn test_set_cell_empty_non_existing_sheet() {
+fn test_cell_clear_contents_non_existing_sheet() {
     let mut model = new_empty_model();
     assert_eq!(
-        model.set_cell_empty(13, 1, 1),
+        model.cell_clear_contents(13, 1, 1),
         Err("Invalid sheet index".to_string())
     );
 }
 
 #[test]
-fn test_set_cell_empty_unset_cell() {
+fn test_cell_clear_contents_unset_cell() {
     let mut model = new_empty_model();
-    model.set_cell_empty(0, 1, 1).unwrap();
+    model.cell_clear_contents(0, 1, 1).unwrap();
     assert_eq!(model.is_empty_cell(0, 1, 1), Ok(true));
     model.evaluate();
     assert_eq!(model._get_text_at(0, 1, 1), "");
 }
 
 #[test]
-fn test_set_cell_empty_with_value() {
+fn test_cell_clear_contents_with_value() {
     let mut model = new_empty_model();
     model._set("A1", "hello");
     model.evaluate();
@@ -28,7 +28,7 @@ fn test_set_cell_empty_with_value() {
     assert_eq!(model._get_text_at(0, 1, 1), "hello");
     assert_eq!(model.is_empty_cell(0, 1, 1), Ok(false));
 
-    model.set_cell_empty(0, 1, 1).unwrap();
+    model.cell_clear_contents(0, 1, 1).unwrap();
     model.evaluate();
 
     assert_eq!(model._get_text_at(0, 1, 1), "");
@@ -36,7 +36,7 @@ fn test_set_cell_empty_with_value() {
 }
 
 #[test]
-fn test_set_cell_empty_referenced_elsewhere() {
+fn test_cell_clear_contents_referenced_elsewhere() {
     let mut model = new_empty_model();
     model._set("A1", "35");
     model._set("A2", "=2*A1");
@@ -47,7 +47,7 @@ fn test_set_cell_empty_referenced_elsewhere() {
     assert_eq!(model.is_empty_cell(0, 1, 1), Ok(false));
     assert_eq!(model.is_empty_cell(0, 2, 1), Ok(false));
 
-    model.set_cell_empty(0, 1, 1).unwrap();
+    model.cell_clear_contents(0, 1, 1).unwrap();
     model.evaluate();
 
     assert_eq!(model._get_text_at(0, 1, 1), "");

base/src/test/test_column_width.rs

@@ -23,10 +23,10 @@ fn test_column_width() {
         .unwrap();
     assert_eq!(model.workbook.worksheets[0].cols.len(), 3);
     let worksheet = model.workbook.worksheet(0).unwrap();
-    assert!((worksheet.column_width(1).unwrap() - DEFAULT_COLUMN_WIDTH).abs() < f64::EPSILON);
-    assert!((worksheet.column_width(2).unwrap() - 30.0).abs() < f64::EPSILON);
-    assert!((worksheet.column_width(3).unwrap() - DEFAULT_COLUMN_WIDTH).abs() < f64::EPSILON);
-    assert_eq!(model.get_cell_style_index(0, 23, 2), 6);
+    assert!((worksheet.get_column_width(1).unwrap() - DEFAULT_COLUMN_WIDTH).abs() < f64::EPSILON);
+    assert!((worksheet.get_column_width(2).unwrap() - 30.0).abs() < f64::EPSILON);
+    assert!((worksheet.get_column_width(3).unwrap() - DEFAULT_COLUMN_WIDTH).abs() < f64::EPSILON);
+    assert_eq!(model.get_cell_style_index(0, 23, 2), Ok(6));
 }
 
 #[test]
@@ -48,10 +48,12 @@ fn test_column_width_lower_edge() {
         .unwrap();
     assert_eq!(model.workbook.worksheets[0].cols.len(), 2);
     let worksheet = model.workbook.worksheet(0).unwrap();
-    assert!((worksheet.column_width(4).unwrap() - DEFAULT_COLUMN_WIDTH).abs() < f64::EPSILON);
-    assert!((worksheet.column_width(5).unwrap() - 30.0).abs() < f64::EPSILON);
-    assert!((worksheet.column_width(6).unwrap() - 10.0 * COLUMN_WIDTH_FACTOR).abs() < f64::EPSILON);
-    assert_eq!(model.get_cell_style_index(0, 23, 5), 1);
+    assert!((worksheet.get_column_width(4).unwrap() - DEFAULT_COLUMN_WIDTH).abs() < f64::EPSILON);
+    assert!((worksheet.get_column_width(5).unwrap() - 30.0).abs() < f64::EPSILON);
+    assert!(
+        (worksheet.get_column_width(6).unwrap() - 10.0 * COLUMN_WIDTH_FACTOR).abs() < f64::EPSILON
+    );
+    assert_eq!(model.get_cell_style_index(0, 23, 5), Ok(1));
 }
 
 #[test]
@@ -74,9 +76,9 @@ fn test_column_width_higher_edge() {
     assert_eq!(model.workbook.worksheets[0].cols.len(), 2);
     let worksheet = model.workbook.worksheet(0).unwrap();
     assert!(
-        (worksheet.column_width(15).unwrap() - 10.0 * COLUMN_WIDTH_FACTOR).abs() < f64::EPSILON
+        (worksheet.get_column_width(15).unwrap() - 10.0 * COLUMN_WIDTH_FACTOR).abs() < f64::EPSILON
     );
-    assert!((worksheet.column_width(16).unwrap() - 30.0).abs() < f64::EPSILON);
-    assert!((worksheet.column_width(17).unwrap() - DEFAULT_COLUMN_WIDTH).abs() < f64::EPSILON);
-    assert_eq!(model.get_cell_style_index(0, 23, 16), 1);
+    assert!((worksheet.get_column_width(16).unwrap() - 30.0).abs() < f64::EPSILON);
+    assert!((worksheet.get_column_width(17).unwrap() - DEFAULT_COLUMN_WIDTH).abs() < f64::EPSILON);
+    assert_eq!(model.get_cell_style_index(0, 23, 16), Ok(1));
 }

base/src/test/test_frozen_rows_and_columns.rs

@@ -8,34 +8,37 @@ use crate::{
 #[test]
 fn test_empty_model() {
     let mut model = new_empty_model();
-    assert_eq!(model.get_frozen_rows(0), Ok(0));
-    assert_eq!(model.get_frozen_columns(0), Ok(0));
+    assert_eq!(model.get_frozen_rows_count(0), Ok(0));
+    assert_eq!(model.get_frozen_columns_count(0), Ok(0));
 
     let e = model.set_frozen_rows(0, 3);
     assert!(e.is_ok());
-    assert_eq!(model.get_frozen_rows(0), Ok(3));
-    assert_eq!(model.get_frozen_columns(0), Ok(0));
+    assert_eq!(model.get_frozen_rows_count(0), Ok(3));
+    assert_eq!(model.get_frozen_columns_count(0), Ok(0));
 
     let e = model.set_frozen_columns(0, 53);
     assert!(e.is_ok());
-    assert_eq!(model.get_frozen_rows(0), Ok(3));
-    assert_eq!(model.get_frozen_columns(0), Ok(53));
+    assert_eq!(model.get_frozen_rows_count(0), Ok(3));
+    assert_eq!(model.get_frozen_columns_count(0), Ok(53));
 
     // Set them back to zero
     let e = model.set_frozen_rows(0, 0);
     assert!(e.is_ok());
     let e = model.set_frozen_columns(0, 0);
     assert!(e.is_ok());
-    assert_eq!(model.get_frozen_rows(0), Ok(0));
-    assert_eq!(model.get_frozen_columns(0), Ok(0));
+    assert_eq!(model.get_frozen_rows_count(0), Ok(0));
+    assert_eq!(model.get_frozen_columns_count(0), Ok(0));
 }
 
 #[test]
 fn test_invalid_sheet() {
     let mut model = new_empty_model();
-    assert_eq!(model.get_frozen_rows(1), Err("Invalid sheet".to_string()));
     assert_eq!(
-        model.get_frozen_columns(3),
+        model.get_frozen_rows_count(1),
+        Err("Invalid sheet".to_string())
+    );
+    assert_eq!(
+        model.get_frozen_columns_count(3),
         Err("Invalid sheet".to_string())
     );
 

base/src/test/test_gc.rs

@@ -1,22 +0,0 @@
-#![allow(clippy::unwrap_used)]
-
-use crate::test::util::new_empty_model;
-
-#[test]
-fn test_empty_model() {
-    let mut model = new_empty_model();
-    // set a string
-    model._set("A1", "Hello");
-    assert_eq!(model.shared_strings.len(), 1);
-    // calling the gc doesn't do anything
-    model.gc().unwrap();
-    assert_eq!(model.shared_strings.len(), 1);
-
-    // If we delete the cell the string is still in the list
-    model.delete_cell(0, 1, 1).unwrap();
-    assert_eq!(model.shared_strings.len(), 1);
-
-    // after the gc the string is no longer present
-    model.gc().unwrap();
-    assert_eq!(model.shared_strings.len(), 0);
-}

base/src/test/test_general.rs

@@ -17,7 +17,9 @@ fn test_empty_model() {
 #[test]
 fn test_model_simple_evaluation() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 1, 1, "= 1 + 3".to_string());
+    model
+        .set_user_input(0, 1, 1, "= 1 + 3".to_string())
+        .unwrap();
     model.evaluate();
     let result = model._get_text_at(0, 1, 1);
     assert_eq!(result, *"4");
@@ -43,7 +45,7 @@ fn test_model_simple_evaluation_order() {
 #[test]
 fn test_model_invalid_formula() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 1, 1, "= 1 +".to_string());
+    model.set_user_input(0, 1, 1, "= 1 +".to_string()).unwrap();
     model.evaluate();
     let result = model._get_text_at(0, 1, 1);
     assert_eq!(result, *"#ERROR!");
@@ -54,8 +56,10 @@ fn test_model_invalid_formula() {
 #[test]
 fn test_model_dependencies() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 1, 1, "23".to_string()); // A1
-    model.set_user_input(0, 1, 2, "= A1* 2-4".to_string()); // B1
+    model.set_user_input(0, 1, 1, "23".to_string()).unwrap(); // A1
+    model
+        .set_user_input(0, 1, 2, "= A1* 2-4".to_string())
+        .unwrap(); // B1
     model.evaluate();
     let result = model._get_text_at(0, 1, 1);
     assert_eq!(result, *"23");
@@ -65,7 +69,9 @@ fn test_model_dependencies() {
     let result = model._get_formula("B1");
     assert_eq!(result, *"=A1*2-4");
 
-    model.set_user_input(0, 2, 1, "=SUM(A1, B1)".to_string()); // A2
+    model
+        .set_user_input(0, 2, 1, "=SUM(A1, B1)".to_string())
+        .unwrap(); // A2
     model.evaluate();
     let result = model._get_text_at(0, 2, 1);
     assert_eq!(result, *"65");
@@ -74,8 +80,10 @@ fn test_model_dependencies() {
 #[test]
 fn test_model_strings() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 1, 1, "Hello World".to_string());
-    model.set_user_input(0, 1, 2, "=A1".to_string());
+    model
+        .set_user_input(0, 1, 1, "Hello World".to_string())
+        .unwrap();
+    model.set_user_input(0, 1, 2, "=A1".to_string()).unwrap();
     model.evaluate();
     let result = model._get_text_at(0, 1, 1);
     assert_eq!(result, *"Hello World");
@@ -152,21 +160,35 @@ fn test_to_excel_precision_str() {
 #[test]
 fn test_booleans() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 1, 1, "true".to_string());
-    model.set_user_input(0, 2, 1, "TRUE".to_string());
-    model.set_user_input(0, 3, 1, "True".to_string());
-    model.set_user_input(0, 4, 1, "false".to_string());
-    model.set_user_input(0, 5, 1, "FALSE".to_string());
-    model.set_user_input(0, 6, 1, "False".to_string());
+    model.set_user_input(0, 1, 1, "true".to_string()).unwrap();
+    model.set_user_input(0, 2, 1, "TRUE".to_string()).unwrap();
+    model.set_user_input(0, 3, 1, "True".to_string()).unwrap();
+    model.set_user_input(0, 4, 1, "false".to_string()).unwrap();
+    model.set_user_input(0, 5, 1, "FALSE".to_string()).unwrap();
+    model.set_user_input(0, 6, 1, "False".to_string()).unwrap();
 
-    model.set_user_input(0, 1, 2, "=ISLOGICAL(A1)".to_string());
-    model.set_user_input(0, 2, 2, "=ISLOGICAL(A2)".to_string());
-    model.set_user_input(0, 3, 2, "=ISLOGICAL(A3)".to_string());
-    model.set_user_input(0, 4, 2, "=ISLOGICAL(A4)".to_string());
-    model.set_user_input(0, 5, 2, "=ISLOGICAL(A5)".to_string());
-    model.set_user_input(0, 6, 2, "=ISLOGICAL(A6)".to_string());
+    model
+        .set_user_input(0, 1, 2, "=ISLOGICAL(A1)".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 2, 2, "=ISLOGICAL(A2)".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 3, 2, "=ISLOGICAL(A3)".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 4, 2, "=ISLOGICAL(A4)".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 5, 2, "=ISLOGICAL(A5)".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 6, 2, "=ISLOGICAL(A6)".to_string())
+        .unwrap();
 
-    model.set_user_input(0, 1, 5, "=IF(false, True, FALSe)".to_string());
+    model
+        .set_user_input(0, 1, 5, "=IF(false, True, FALSe)".to_string())
+        .unwrap();
 
     model.evaluate();
 
@@ -191,19 +213,19 @@ fn test_booleans() {
 #[test]
 fn test_set_cell_style() {
     let mut model = new_empty_model();
-    let mut style = model.get_style_for_cell(0, 1, 1);
+    let mut style = model.get_style_for_cell(0, 1, 1).unwrap();
     assert!(!style.font.b);
 
     style.font.b = true;
     assert!(model.set_cell_style(0, 1, 1, &style).is_ok());
 
-    let mut style = model.get_style_for_cell(0, 1, 1);
+    let mut style = model.get_style_for_cell(0, 1, 1).unwrap();
     assert!(style.font.b);
 
     style.font.b = false;
     assert!(model.set_cell_style(0, 1, 1, &style).is_ok());
 
-    let style = model.get_style_for_cell(0, 1, 1);
+    let style = model.get_style_for_cell(0, 1, 1).unwrap();
     assert!(!style.font.b);
 }
 
@@ -211,21 +233,21 @@ fn test_set_cell_style() {
 fn test_copy_cell_style() {
     let mut model = new_empty_model();
 
-    let mut style = model.get_style_for_cell(0, 1, 1);
+    let mut style = model.get_style_for_cell(0, 1, 1).unwrap();
     style.font.b = true;
     assert!(model.set_cell_style(0, 1, 1, &style).is_ok());
 
-    let mut style = model.get_style_for_cell(0, 1, 2);
+    let mut style = model.get_style_for_cell(0, 1, 2).unwrap();
     style.font.i = true;
     assert!(model.set_cell_style(0, 1, 2, &style).is_ok());
 
     assert!(model.copy_cell_style((0, 1, 1), (0, 1, 2)).is_ok());
 
-    let style = model.get_style_for_cell(0, 1, 1);
+    let style = model.get_style_for_cell(0, 1, 1).unwrap();
     assert!(style.font.b);
     assert!(!style.font.i);
 
-    let style = model.get_style_for_cell(0, 1, 2);
+    let style = model.get_style_for_cell(0, 1, 2).unwrap();
     assert!(style.font.b);
     assert!(!style.font.i);
 }
@@ -234,15 +256,15 @@ fn test_copy_cell_style() {
 fn test_get_cell_style_index() {
     let mut model = new_empty_model();
 
-    let mut style = model.get_style_for_cell(0, 1, 1);
-    let style_index = model.get_cell_style_index(0, 1, 1);
+    let mut style = model.get_style_for_cell(0, 1, 1).unwrap();
+    let style_index = model.get_cell_style_index(0, 1, 1).unwrap();
     assert_eq!(style_index, 0);
     assert!(!style.font.b);
 
     style.font.b = true;
     assert!(model.set_cell_style(0, 1, 1, &style).is_ok());
 
-    let style_index = model.get_cell_style_index(0, 1, 1);
+    let style_index = model.get_cell_style_index(0, 1, 1).unwrap();
     assert_eq!(style_index, 1);
 }
 
@@ -250,29 +272,29 @@ fn test_get_cell_style_index() {
 fn test_model_set_cells_with_values_styles() {
     let mut model = new_empty_model();
     // Inputs
-    model.set_user_input(0, 1, 1, "21".to_string()); // A1
-    model.set_user_input(0, 2, 1, "2".to_string()); // A2
+    model.set_user_input(0, 1, 1, "21".to_string()).unwrap(); // A1
+    model.set_user_input(0, 2, 1, "2".to_string()).unwrap(); // A2
 
-    let style_index = model.get_cell_style_index(0, 1, 1);
+    let style_index = model.get_cell_style_index(0, 1, 1).unwrap();
     assert_eq!(style_index, 0);
-    let mut style = model.get_style_for_cell(0, 1, 1);
+    let mut style = model.get_style_for_cell(0, 1, 1).unwrap();
     style.font.b = true;
     assert!(model.set_cell_style(0, 1, 1, &style).is_ok());
     assert!(model.set_cell_style(0, 2, 1, &style).is_ok());
-    let style_index = model.get_cell_style_index(0, 1, 1);
+    let style_index = model.get_cell_style_index(0, 1, 1).unwrap();
     assert_eq!(style_index, 1);
-    let style_index = model.get_cell_style_index(0, 2, 1);
+    let style_index = model.get_cell_style_index(0, 2, 1).unwrap();
     assert_eq!(style_index, 1);
 
-    model.update_cell_with_number(0, 1, 2, 1.0);
-    model.update_cell_with_number(0, 2, 1, 2.0);
+    model.update_cell_with_number(0, 1, 2, 1.0).unwrap();
+    model.update_cell_with_number(0, 2, 1, 2.0).unwrap();
 
     model.evaluate();
 
     // Styles are not modified
-    let style_index = model.get_cell_style_index(0, 1, 1);
+    let style_index = model.get_cell_style_index(0, 1, 1).unwrap();
     assert_eq!(style_index, 1);
-    let style_index = model.get_cell_style_index(0, 2, 1);
+    let style_index = model.get_cell_style_index(0, 2, 1).unwrap();
     assert_eq!(style_index, 1);
 }
 
@@ -280,20 +302,20 @@ fn test_model_set_cells_with_values_styles() {
 fn test_style_fmt_id() {
     let mut model = new_empty_model();
 
-    let mut style = model.get_style_for_cell(0, 1, 1);
+    let mut style = model.get_style_for_cell(0, 1, 1).unwrap();
     style.num_fmt = "#.##".to_string();
     assert!(model.set_cell_style(0, 1, 1, &style).is_ok());
-    let style = model.get_style_for_cell(0, 1, 1);
+    let style = model.get_style_for_cell(0, 1, 1).unwrap();
     assert_eq!(style.num_fmt, "#.##");
 
-    let mut style = model.get_style_for_cell(0, 10, 1);
+    let mut style = model.get_style_for_cell(0, 10, 1).unwrap();
     style.num_fmt = "$$#,##0.0000".to_string();
     assert!(model.set_cell_style(0, 10, 1, &style).is_ok());
-    let style = model.get_style_for_cell(0, 10, 1);
+    let style = model.get_style_for_cell(0, 10, 1).unwrap();
     assert_eq!(style.num_fmt, "$$#,##0.0000");
 
     // Make sure old style is not touched
-    let style = model.get_style_for_cell(0, 1, 1);
+    let style = model.get_style_for_cell(0, 1, 1).unwrap();
     assert_eq!(style.num_fmt, "#.##");
 }
 
@@ -357,9 +379,13 @@ fn set_input_autocomplete() {
     let mut model = new_empty_model();
     model._set("A1", "1");
     model._set("A2", "2");
-    model.set_user_input(0, 3, 1, "=SUM(A1:A2".to_string());
+    model
+        .set_user_input(0, 3, 1, "=SUM(A1:A2".to_string())
+        .unwrap();
     // This will fail anyway
-    model.set_user_input(0, 4, 1, "=SUM(A1*".to_string());
+    model
+        .set_user_input(0, 4, 1, "=SUM(A1*".to_string())
+        .unwrap();
     model.evaluate();
 
     assert_eq!(model._get_formula("A3"), "=SUM(A1:A2)");
@@ -405,17 +431,17 @@ fn test_get_formatted_cell_value() {
     model._set("A5", "123.456");
 
     // change A5 format
-    let mut style = model.get_style_for_cell(0, 5, 1);
+    let mut style = model.get_style_for_cell(0, 5, 1).unwrap();
     style.num_fmt = "$#,##0.00".to_string();
     model.set_cell_style(0, 5, 1, &style).unwrap();
 
     model.evaluate();
 
-    assert_eq!(model.formatted_cell_value(0, 1, 1).unwrap(), "foobar");
-    assert_eq!(model.formatted_cell_value(0, 2, 1).unwrap(), "TRUE");
-    assert_eq!(model.formatted_cell_value(0, 3, 1).unwrap(), "");
-    assert_eq!(model.formatted_cell_value(0, 4, 1).unwrap(), "123.456");
-    assert_eq!(model.formatted_cell_value(0, 5, 1).unwrap(), "$123.46");
+    assert_eq!(model.get_formatted_cell_value(0, 1, 1).unwrap(), "foobar");
+    assert_eq!(model.get_formatted_cell_value(0, 2, 1).unwrap(), "TRUE");
+    assert_eq!(model.get_formatted_cell_value(0, 3, 1).unwrap(), "");
+    assert_eq!(model.get_formatted_cell_value(0, 4, 1).unwrap(), "123.456");
+    assert_eq!(model.get_formatted_cell_value(0, 5, 1).unwrap(), "$123.46");
 }
 
 #[test]
@@ -426,20 +452,20 @@ fn test_cell_formula() {
     model.evaluate();
 
     assert_eq!(
-        model.cell_formula(0, 1, 1), // A1
+        model.get_cell_formula(0, 1, 1), // A1
         Ok(Some("=1+2+3".to_string())),
     );
     assert_eq!(
-        model.cell_formula(0, 2, 1), // A2
+        model.get_cell_formula(0, 2, 1), // A2
         Ok(None),
     );
     assert_eq!(
-        model.cell_formula(0, 3, 1), // A3 - empty cell
+        model.get_cell_formula(0, 3, 1), // A3 - empty cell
         Ok(None),
     );
 
     assert_eq!(
-        model.cell_formula(42, 1, 1),
+        model.get_cell_formula(42, 1, 1),
         Err("Invalid sheet index".to_string()),
     );
 }
@@ -453,16 +479,16 @@ fn test_xlfn() {
     model.evaluate();
     // Only modern formulas strip the '_xlfn.'
     assert_eq!(
-        model.cell_formula(0, 1, 1).unwrap(),
+        model.get_cell_formula(0, 1, 1).unwrap(),
         Some("=_xlfn.SIN(1)".to_string())
     );
     // unknown formulas keep the '_xlfn.' prefix
     assert_eq!(
-        model.cell_formula(0, 2, 1).unwrap(),
+        model.get_cell_formula(0, 2, 1).unwrap(),
         Some("=_xlfn.SINY(1)".to_string())
     );
     assert_eq!(
-        model.cell_formula(0, 3, 1).unwrap(),
+        model.get_cell_formula(0, 3, 1).unwrap(),
         Some("=CONCAT(3,4)".to_string())
     );
 }
@@ -474,11 +500,11 @@ fn test_letter_case() {
     model._set("A2", "=sIn(2)");
     model.evaluate();
     assert_eq!(
-        model.cell_formula(0, 1, 1).unwrap(),
+        model.get_cell_formula(0, 1, 1).unwrap(),
         Some("=SIN(1)".to_string())
     );
     assert_eq!(
-        model.cell_formula(0, 2, 1).unwrap(),
+        model.get_cell_formula(0, 2, 1).unwrap(),
         Some("=SIN(2)".to_string())
     );
 }

base/src/test/test_get_cell_content.rs

@@ -5,8 +5,12 @@ use crate::test::util::new_empty_model;
 #[test]
 fn test_formulas() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 1, 1, "$100.348".to_string());
-    model.set_user_input(0, 1, 2, "=ISNUMBER(A1)".to_string());
+    model
+        .set_user_input(0, 1, 1, "$100.348".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 1, 2, "=ISNUMBER(A1)".to_string())
+        .unwrap();
 
     model.evaluate();
 

base/src/test/test_metadata.rs

@@ -3,7 +3,7 @@ use crate::test::util::new_empty_model;
 #[test]
 fn test_metadata_new_model() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 1, 1, "5.5".to_string());
+    model.set_user_input(0, 1, 1, "5.5".to_string()).unwrap();
     model.evaluate();
     let metadata = &model.workbook.metadata;
     assert_eq!(metadata.application, "IronCalc Sheets");

base/src/test/test_model_cell_clear_all.rs

@@ -2,22 +2,22 @@
 use crate::test::util::new_empty_model;
 
 #[test]
-fn test_delete_cell_non_existing_sheet() {
+fn test_cell_clear_all_non_existing_sheet() {
     let mut model = new_empty_model();
     assert_eq!(
-        model.delete_cell(13, 1, 1),
+        model.cell_clear_all(13, 1, 1),
         Err("Invalid sheet index".to_string())
     );
 }
 
 #[test]
-fn test_delete_cell_unset_cell() {
+fn test_cell_clear_all_unset_cell() {
     let mut model = new_empty_model();
-    assert!(model.delete_cell(0, 1, 1).is_ok());
+    assert!(model.cell_clear_all(0, 1, 1).is_ok());
 }
 
 #[test]
-fn test_delete_cell_with_value() {
+fn test_cell_clear_all_with_value() {
     let mut model = new_empty_model();
     model._set("A1", "hello");
     model.evaluate();
@@ -25,7 +25,7 @@ fn test_delete_cell_with_value() {
     assert_eq!(model._get_text_at(0, 1, 1), "hello");
     assert_eq!(model.is_empty_cell(0, 1, 1), Ok(false));
 
-    model.delete_cell(0, 1, 1).unwrap();
+    model.cell_clear_all(0, 1, 1).unwrap();
     model.evaluate();
 
     assert_eq!(model._get_text_at(0, 1, 1), "");
@@ -33,7 +33,7 @@ fn test_delete_cell_with_value() {
 }
 
 #[test]
-fn test_delete_cell_referenced_elsewhere() {
+fn test_cell_clear_all_referenced_elsewhere() {
     let mut model = new_empty_model();
     model._set("A1", "35");
     model._set("A2", "=2*A1");
@@ -44,7 +44,7 @@ fn test_delete_cell_referenced_elsewhere() {
     assert_eq!(model.is_empty_cell(0, 1, 1), Ok(false));
     assert_eq!(model.is_empty_cell(0, 2, 1), Ok(false));
 
-    model.delete_cell(0, 1, 1).unwrap();
+    model.cell_clear_all(0, 1, 1).unwrap();
     model.evaluate();
 
     assert_eq!(model._get_text_at(0, 1, 1), "");

base/src/test/test_model_is_empty_cell.rs

@@ -14,9 +14,11 @@ fn test_is_empty_cell_non_existing_sheet() {
 fn test_is_empty_cell() {
     let mut model = new_empty_model();
     assert!(model.is_empty_cell(0, 3, 1).unwrap());
-    model.set_user_input(0, 3, 1, "Hello World".to_string());
+    model
+        .set_user_input(0, 3, 1, "Hello World".to_string())
+        .unwrap();
     assert!(!model.is_empty_cell(0, 3, 1).unwrap());
-    model.set_cell_empty(0, 3, 1).unwrap();
+    model.cell_clear_contents(0, 3, 1).unwrap();
     assert!(model.is_empty_cell(0, 3, 1).unwrap());
 }
 

base/src/test/test_quote_prefix.rs

@@ -57,12 +57,12 @@ fn test_quote_prefix_enter() {
     model._set("A2", "=ISTEXT(A1)");
     model.evaluate();
     // We introduce a value with a "quote prefix" index
-    model.set_user_input(0, 1, 3, "'=A1".to_string());
+    model.set_user_input(0, 1, 3, "'=A1".to_string()).unwrap();
     model.evaluate();
     assert_eq!(model._get_text("C1"), *"=A1");
 
     // But if we enter with a quote_prefix but without the "'" it won't be quote_prefix
-    model.set_user_input(0, 1, 4, "=A1".to_string());
+    model.set_user_input(0, 1, 4, "=A1".to_string()).unwrap();
     model.evaluate();
     assert_eq!(model._get_text("D1"), *"123");
 }
@@ -75,7 +75,7 @@ fn test_quote_prefix_reenter() {
     model.evaluate();
     assert_eq!(model._get_text("A2"), *"TRUE");
     // We introduce a value with a "quote prefix" index
-    model.set_user_input(0, 1, 1, "123".to_string());
+    model.set_user_input(0, 1, 1, "123".to_string()).unwrap();
     model.evaluate();
     assert_eq!(model._get_text("A2"), *"FALSE");
 }
@@ -83,7 +83,7 @@ fn test_quote_prefix_reenter() {
 #[test]
 fn test_update_cell_quote() {
     let mut model = new_empty_model();
-    model.update_cell_with_text(0, 1, 1, "= 1 + 3");
+    model.update_cell_with_text(0, 1, 1, "= 1 + 3").unwrap();
     model.evaluate();
     assert_eq!(model._get_text("A1"), *"= 1 + 3");
     assert!(!model._has_formula("A1"));
@@ -92,12 +92,12 @@ fn test_update_cell_quote() {
 #[test]
 fn test_update_quote_prefix_reenter() {
     let mut model = new_empty_model();
-    model.update_cell_with_text(0, 1, 1, "123");
+    model.update_cell_with_text(0, 1, 1, "123").unwrap();
     model._set("A2", "=ISTEXT(A1)");
     model.evaluate();
     assert_eq!(model._get_text("A2"), *"TRUE");
     // We reenter as a number
-    model.update_cell_with_number(0, 1, 1, 123.0);
+    model.update_cell_with_number(0, 1, 1, 123.0).unwrap();
     model.evaluate();
     assert_eq!(model._get_text("A2"), *"FALSE");
 }
@@ -105,12 +105,12 @@ fn test_update_quote_prefix_reenter() {
 #[test]
 fn test_update_quote_prefix_reenter_bool() {
     let mut model = new_empty_model();
-    model.update_cell_with_text(0, 1, 1, "TRUE");
+    model.update_cell_with_text(0, 1, 1, "TRUE").unwrap();
     model._set("A2", "=ISTEXT(A1)");
     model.evaluate();
     assert_eq!(model._get_text("A2"), *"TRUE");
     // We enter a bool
-    model.update_cell_with_bool(0, 1, 1, true);
+    model.update_cell_with_bool(0, 1, 1, true).unwrap();
     model.evaluate();
     assert_eq!(model._get_text("A2"), *"FALSE");
 }
@@ -118,29 +118,29 @@ fn test_update_quote_prefix_reenter_bool() {
 #[test]
 fn test_update_quote_prefix_reenter_text() {
     let mut model = new_empty_model();
-    model.update_cell_with_text(0, 1, 1, "123");
+    model.update_cell_with_text(0, 1, 1, "123").unwrap();
     model._set("A2", "=ISTEXT(A1)");
     model.evaluate();
     assert_eq!(model._get_text("A2"), *"TRUE");
-    assert!(model.get_style_for_cell(0, 1, 1).quote_prefix);
+    assert!(model.get_style_for_cell(0, 1, 1).unwrap().quote_prefix);
     // We enter a string
-    model.update_cell_with_text(0, 1, 1, "Hello");
+    model.update_cell_with_text(0, 1, 1, "Hello").unwrap();
     model.evaluate();
     assert_eq!(model._get_text("A2"), *"TRUE");
-    assert!(!model.get_style_for_cell(0, 1, 1).quote_prefix);
+    assert!(!model.get_style_for_cell(0, 1, 1).unwrap().quote_prefix);
 }
 
 #[test]
 fn test_update_quote_prefix_reenter_text_2() {
     let mut model = new_empty_model();
-    model.update_cell_with_text(0, 1, 1, "123");
+    model.update_cell_with_text(0, 1, 1, "123").unwrap();
     model._set("A2", "=ISTEXT(A1)");
     model.evaluate();
     assert_eq!(model._get_text("A2"), *"TRUE");
-    assert!(model.get_style_for_cell(0, 1, 1).quote_prefix);
+    assert!(model.get_style_for_cell(0, 1, 1).unwrap().quote_prefix);
     // We enter another number
-    model.update_cell_with_text(0, 1, 1, "42");
+    model.update_cell_with_text(0, 1, 1, "42").unwrap();
     model.evaluate();
     assert_eq!(model._get_text("A2"), *"TRUE");
-    assert!(model.get_style_for_cell(0, 1, 1).quote_prefix);
+    assert!(model.get_style_for_cell(0, 1, 1).unwrap().quote_prefix);
 }

base/src/test/test_set_functions_error_handling.rs

@@ -0,0 +1,449 @@
+use crate::{expressions::token, test::util::new_empty_model, types::Cell};
+
+#[test]
+fn test_update_cell_with_text() {
+    let mut model = new_empty_model();
+
+    // Below are safe inputs
+    model.set_user_input(0, 1, 1, "Hello".to_string()).unwrap();
+
+    // Now testing all the possible error scenarios
+
+    // Case1 : Invalid sheet
+    let update_result = model.update_cell_with_text(1, 1, 1, "new value");
+    assert_eq!(update_result, Err("Invalid sheet index".to_string()));
+
+    // Case2 : Invalid Row
+    let update_result = model.update_cell_with_text(0, 0, 1, "new value");
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+
+    // Case3 : Invalid Column
+    let update_result = model.update_cell_with_text(0, 1, 1048579, "new value");
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+}
+
+#[test]
+fn test_update_cell_with_number() {
+    let mut model = new_empty_model();
+
+    // Below are safe inputs
+    model.update_cell_with_number(0, 1, 1, 10.0).unwrap();
+
+    // Now testing all the possible error scenarios
+
+    // Case1 : Invalid sheet
+    let update_result = model.update_cell_with_number(1, 1, 1, 20.0);
+    assert_eq!(update_result, Err("Invalid sheet index".to_string()));
+
+    // Case2 : Invalid Row
+    let update_result = model.update_cell_with_number(0, 0, 1, 20.0);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+
+    // Case3 : Invalid Column
+    let update_result = model.update_cell_with_number(0, 1, 1048579, 20.0);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+}
+
+#[test]
+fn test_update_cell_with_bool() {
+    let mut model = new_empty_model();
+
+    // Below are safe inputs
+    model.update_cell_with_bool(0, 1, 1, true).unwrap();
+
+    // Now testing all the possible error scenarios
+
+    // Case1 : Invalid sheet
+    let update_result = model.update_cell_with_bool(1, 1, 1, false);
+    assert_eq!(update_result, Err("Invalid sheet index".to_string()));
+
+    // Case2 : Invalid Row
+    let update_result = model.update_cell_with_bool(0, 0, 1, false);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+
+    // Case3 : Invalid Column
+    let update_result = model.update_cell_with_bool(0, 1, 1048579, false);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+}
+
+#[test]
+fn test_update_cell_with_formula() {
+    let mut model = new_empty_model();
+
+    // Below are safe inputs
+    model.update_cell_with_number(0, 1, 1, 10.0).unwrap();
+    model
+        .update_cell_with_formula(0, 1, 2, "=A1*2".to_string())
+        .unwrap();
+
+    model.evaluate();
+    // Now testing all the possible error scenarios
+
+    // Case1 : Invalid sheet
+    let update_result = model.update_cell_with_formula(1, 1, 2, "=A1*2".to_string());
+    assert_eq!(update_result, Err("Invalid sheet index".to_string()));
+
+    // Case2 : Invalid Row
+    let update_result = model.update_cell_with_formula(0, 0, 2, "=A1*2".to_string());
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+
+    // Case3 : Invalid Column
+    let update_result = model.update_cell_with_formula(0, 1, 1048579, "=A1*2".to_string());
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+}
+
+#[test]
+fn test_set_user_input() {
+    let mut model = new_empty_model();
+
+    // Below are safe inputs
+    model.update_cell_with_number(0, 1, 1, 10.0).unwrap();
+    model.evaluate();
+    // Now testing all the possible error scenarios
+
+    // Case1 : Invalid sheet
+    let update_result = model.set_user_input(1, 1, 2, "20.0".to_string());
+    assert_eq!(update_result, Err("Invalid sheet index".to_string()));
+
+    // Case2 : Invalid Row
+    let update_result = model.set_user_input(0, 0, 2, "20.0".to_string());
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+
+    // Case3 : Invalid Column
+    let update_result = model.set_user_input(0, 1, 1048579, "20.0".to_string());
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+}
+
+#[test]
+fn test_get_style_for_cell() {
+    let mut model = new_empty_model();
+
+    // Below are safe inputs
+    model.update_cell_with_number(0, 1, 1, 10.0).unwrap();
+    model.evaluate();
+    // Now testing all the possible error scenarios
+
+    // Case1 : Invalid sheet
+    let update_result = model.get_style_for_cell(1, 1, 2);
+    assert_eq!(update_result, Err("Invalid sheet index".to_string()));
+
+    // ATTENTION : get_cell_style_index tries to get cell using row and col
+    // if we invalid row or column is given, it will return index 0.
+
+    // Case2 : Invalid Row
+    let update_result = model.get_style_for_cell(0, 0, 2);
+    assert!(update_result.is_ok());
+
+    // Case3 : Invalid Column
+    let update_result = model.get_style_for_cell(0, 1, 1048579);
+    assert!(update_result.is_ok());
+}
+
+#[test]
+fn test_get_cell_style_index() {
+    let mut model = new_empty_model();
+
+    // Below are safe inputs
+    model.update_cell_with_number(0, 1, 1, 10.0).unwrap();
+    model.evaluate();
+    // Now testing all the possible error scenarios
+
+    // Case1 : Invalid sheet
+    let update_result = model.get_cell_style_index(1, 1, 2);
+    assert_eq!(update_result, Err("Invalid sheet index".to_string()));
+
+    // ATTENTION : get_cell_style_index tries to get cell using row and col
+    // if we invalid row or column is given, it will return index 0.
+
+    // Case2 : Invalid Row
+    let update_result = model.get_cell_style_index(0, 0, 2);
+    assert_eq!(update_result, Ok(0));
+
+    // Case3 : Invalid Column
+    let update_result = model.get_cell_style_index(0, 1, 1048579);
+    assert_eq!(update_result, Ok(0));
+}
+
+#[test]
+fn test_worksheet_update_cell() {
+    let mut model = new_empty_model();
+
+    // Now testing all the possible error scenarios
+
+    // Case1 : Invalid Row
+    let update_result =
+        model
+            .workbook
+            .worksheet_mut(0)
+            .unwrap()
+            .update_cell(0, 1, Cell::new_number(10.0, 1));
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+
+    // Case2 : Invalid Column
+    let update_result =
+        model
+            .workbook
+            .worksheet_mut(0)
+            .unwrap()
+            .update_cell(1, 1048579, Cell::new_number(10.0, 1));
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+}
+
+#[test]
+fn test_worksheet_set_cell_style() {
+    let mut model = new_empty_model();
+
+    // Now testing all the possible error scenarios
+
+    // Case1 : Invalid Row
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .set_cell_style(0, 1, 1);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+
+    // Case2 : Invalid Column
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .set_cell_style(1, 1048579, 1);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+}
+
+#[test]
+fn test_worksheet_set_cell_with_formula() {
+    let mut model = new_empty_model();
+
+    // Now testing all the possible error scenarios
+
+    // Case1 : Invalid Row
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .set_cell_with_formula(0, 1, 1, 1);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+
+    // Case2 : Invalid Column
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .set_cell_with_formula(1, 1048579, 1, 1);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+}
+
+#[test]
+fn test_worksheet_set_cell_with_number() {
+    let mut model = new_empty_model();
+
+    // Now testing all the possible error scenarios
+
+    // Case1 : Invalid Row
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .set_cell_with_number(0, 1, 1.0, 1);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+
+    // Case2 : Invalid Column
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .set_cell_with_number(1, 1048579, 1.0, 1);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+}
+
+#[test]
+fn test_worksheet_set_cell_with_string() {
+    let mut model = new_empty_model();
+
+    // Now testing all the possible error scenarios
+
+    // Case1 : Invalid Row
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .set_cell_with_string(0, 1, 1, 1);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+
+    // Case2 : Invalid Column
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .set_cell_with_string(1, 1048579, 1, 1);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+}
+
+#[test]
+fn test_worksheet_set_cell_with_boolean() {
+    let mut model = new_empty_model();
+
+    // Now testing all the possible error scenarios
+
+    // Case1 : Invalid Row
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .set_cell_with_boolean(0, 1, true, 1);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+
+    // Case2 : Invalid Column
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .set_cell_with_boolean(1, 1048579, true, 1);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+}
+
+#[test]
+fn test_worksheet_set_cell_with_error() {
+    let mut model = new_empty_model();
+
+    // Now testing all the possible error scenarios
+
+    // Case1: Invalid Row
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .set_cell_with_error(0, 1, token::Error::ERROR, 1);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+
+    // Case2 : Invalid Column
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .set_cell_with_error(1, 1048579, token::Error::ERROR, 1);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+}
+
+#[test]
+fn test_worksheet_cell_clear_contents() {
+    let mut model = new_empty_model();
+
+    model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .update_cell(1, 1, Cell::new_number(10.0, 1))
+        .unwrap();
+    // Now testing all the possible error scenarios
+
+    // Case1 : Invalid Row
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .cell_clear_contents(0, 1);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+
+    // Case2 : Invalid Column
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .cell_clear_contents(1, 1048579);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+
+    // Case3 : Valid case
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .cell_clear_contents(1, 1);
+    assert_eq!(update_result, Ok(()))
+}
+
+#[test]
+fn test_worksheet_cell_clear_contents_with_style() {
+    let mut model = new_empty_model();
+
+    model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .update_cell(1, 1, Cell::new_number(10.0, 1))
+        .unwrap();
+    // Now testing all the possible error scenarios
+
+    // Case1 : Invalid Row
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .cell_clear_contents_with_style(0, 1, 1);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+
+    // Case2 : Invalid Column
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .cell_clear_contents_with_style(1, 1048579, 1);
+    assert_eq!(update_result, Err("Incorrect row or column".to_string()));
+
+    // Case3 : Valid case
+    let update_result = model
+        .workbook
+        .worksheet_mut(0)
+        .unwrap()
+        .cell_clear_contents_with_style(1, 1, 1);
+    assert_eq!(update_result, Ok(()))
+}
+
+#[test]
+fn workbook_styles_get_style_error_handling() {
+    let model = new_empty_model();
+
+    // case 1 : Invalid index
+    assert_eq!(
+        model.workbook.styles.get_style(15),
+        Err("Invalid index provided".to_string())
+    );
+}
+
+#[test]
+fn workbook_styles_get_style_without_quote_prefix_error_handling() {
+    let mut model = new_empty_model();
+
+    // case 1 : Invalid index
+    assert_eq!(
+        model.workbook.styles.get_style_without_quote_prefix(15),
+        Err("Invalid index provided".to_string())
+    );
+}
+
+#[test]
+fn workbook_styles_get_style_with_format_error_handling() {
+    let mut model = new_empty_model();
+
+    // case 1 : Invalid index
+    assert_eq!(
+        model
+            .workbook
+            .styles
+            .get_style_with_format(15, "dummy_num_format"),
+        Err("Invalid index provided".to_string())
+    );
+}
+
+#[test]
+fn workbook_styles_get_style_with_quote_prefix_handling() {
+    let mut model = new_empty_model();
+
+    // case 1 : Invalid index
+    assert_eq!(
+        model.workbook.styles.get_style_with_quote_prefix(15),
+        Err("Invalid index provided".to_string())
+    );
+}

base/src/test/test_set_user_input.rs

@@ -5,16 +5,28 @@ use crate::{cell::CellValue, test::util::new_empty_model};
 #[test]
 fn test_currencies() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 1, 1, "$100.348".to_string());
-    model.set_user_input(0, 1, 2, "=ISNUMBER(A1)".to_string());
+    model
+        .set_user_input(0, 1, 1, "$100.348".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 1, 2, "=ISNUMBER(A1)".to_string())
+        .unwrap();
 
-    model.set_user_input(0, 2, 1, "$ 100.348".to_string());
-    model.set_user_input(0, 2, 2, "=ISNUMBER(A2)".to_string());
+    model
+        .set_user_input(0, 2, 1, "$ 100.348".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 2, 2, "=ISNUMBER(A2)".to_string())
+        .unwrap();
 
-    model.set_user_input(0, 3, 1, "100$".to_string());
-    model.set_user_input(0, 3, 2, "=ISNUMBER(A3)".to_string());
+    model.set_user_input(0, 3, 1, "100$".to_string()).unwrap();
+    model
+        .set_user_input(0, 3, 2, "=ISNUMBER(A3)".to_string())
+        .unwrap();
 
-    model.set_user_input(0, 4, 1, "3.1415926$".to_string());
+    model
+        .set_user_input(0, 4, 1, "3.1415926$".to_string())
+        .unwrap();
 
     model.evaluate();
 
@@ -43,9 +55,9 @@ fn test_currencies() {
 #[test]
 fn scientific() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 1, 1, "3e-4".to_string());
-    model.set_user_input(0, 2, 1, "5e-4$".to_string());
-    model.set_user_input(0, 3, 1, "6e-4%".to_string());
+    model.set_user_input(0, 1, 1, "3e-4".to_string()).unwrap();
+    model.set_user_input(0, 2, 1, "5e-4$".to_string()).unwrap();
+    model.set_user_input(0, 3, 1, "6e-4%".to_string()).unwrap();
 
     model.evaluate();
 
@@ -61,9 +73,13 @@ fn scientific() {
 #[test]
 fn test_percentage() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 10, 1, "50%".to_string());
-    model.set_user_input(0, 10, 2, "=ISNUMBER(A10)".to_string());
-    model.set_user_input(0, 11, 1, "55.759%".to_string());
+    model.set_user_input(0, 10, 1, "50%".to_string()).unwrap();
+    model
+        .set_user_input(0, 10, 2, "=ISNUMBER(A10)".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 11, 1, "55.759%".to_string())
+        .unwrap();
 
     model.evaluate();
 
@@ -81,8 +97,8 @@ fn test_percentage_ops() {
     let mut model = new_empty_model();
     model._set("A1", "5%");
     model._set("A2", "20%");
-    model.set_user_input(0, 3, 1, "=A1+A2".to_string());
-    model.set_user_input(0, 4, 1, "=A1*A2".to_string());
+    model.set_user_input(0, 3, 1, "=A1+A2".to_string()).unwrap();
+    model.set_user_input(0, 4, 1, "=A1*A2".to_string()).unwrap();
 
     model.evaluate();
 
@@ -93,11 +109,19 @@ fn test_percentage_ops() {
 #[test]
 fn test_numbers() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 1, 1, "1,000,000".to_string());
+    model
+        .set_user_input(0, 1, 1, "1,000,000".to_string())
+        .unwrap();
 
-    model.set_user_input(0, 20, 1, "50,123.549".to_string());
-    model.set_user_input(0, 21, 1, "50,12.549".to_string());
-    model.set_user_input(0, 22, 1, "1,234567".to_string());
+    model
+        .set_user_input(0, 20, 1, "50,123.549".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 21, 1, "50,12.549".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 22, 1, "1,234567".to_string())
+        .unwrap();
 
     model.evaluate();
 
@@ -131,7 +155,7 @@ fn test_numbers() {
 #[test]
 fn test_negative_numbers() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 1, 1, "-100".to_string());
+    model.set_user_input(0, 1, 1, "-100".to_string()).unwrap();
 
     model.evaluate();
 
@@ -144,15 +168,19 @@ fn test_negative_numbers() {
 #[test]
 fn test_negative_currencies() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 1, 1, "-$100".to_string());
-    model.set_user_input(0, 2, 1, "-$99.123".to_string());
+    model.set_user_input(0, 1, 1, "-$100".to_string()).unwrap();
+    model
+        .set_user_input(0, 2, 1, "-$99.123".to_string())
+        .unwrap();
     // This is valid!
-    model.set_user_input(0, 3, 1, "$-345".to_string());
+    model.set_user_input(0, 3, 1, "$-345".to_string()).unwrap();
 
-    model.set_user_input(0, 1, 2, "-200$".to_string());
-    model.set_user_input(0, 2, 2, "-92.689$".to_string());
+    model.set_user_input(0, 1, 2, "-200$".to_string()).unwrap();
+    model
+        .set_user_input(0, 2, 2, "-92.689$".to_string())
+        .unwrap();
     // This is valid!
-    model.set_user_input(0, 3, 2, "-22$".to_string());
+    model.set_user_input(0, 3, 2, "-22$".to_string()).unwrap();
 
     model.evaluate();
 
@@ -174,8 +202,10 @@ fn test_formulas() {
     let mut model = new_empty_model();
     model._set("A1", "$100");
     model._set("A2", "$200");
-    model.set_user_input(0, 3, 1, "=A1+A2".to_string());
-    model.set_user_input(0, 4, 1, "=SUM(A1:A3)".to_string());
+    model.set_user_input(0, 3, 1, "=A1+A2".to_string()).unwrap();
+    model
+        .set_user_input(0, 4, 1, "=SUM(A1:A3)".to_string())
+        .unwrap();
 
     model.evaluate();
 
@@ -198,9 +228,9 @@ fn test_product() {
     model._set("A2", "$5");
     model._set("A3", "4");
 
-    model.set_user_input(0, 1, 2, "=A1*A2".to_string());
-    model.set_user_input(0, 2, 2, "=A1*A3".to_string());
-    model.set_user_input(0, 3, 2, "=A1*3".to_string());
+    model.set_user_input(0, 1, 2, "=A1*A2".to_string()).unwrap();
+    model.set_user_input(0, 2, 2, "=A1*A3".to_string()).unwrap();
+    model.set_user_input(0, 3, 2, "=A1*3".to_string()).unwrap();
 
     model.evaluate();
 
@@ -216,10 +246,12 @@ fn test_division() {
     model._set("A2", "$5");
     model._set("A3", "4");
 
-    model.set_user_input(0, 1, 2, "=A1/A2".to_string());
-    model.set_user_input(0, 2, 2, "=A1/A3".to_string());
-    model.set_user_input(0, 3, 2, "=A1/2".to_string());
-    model.set_user_input(0, 4, 2, "=100/A2".to_string());
+    model.set_user_input(0, 1, 2, "=A1/A2".to_string()).unwrap();
+    model.set_user_input(0, 2, 2, "=A1/A3".to_string()).unwrap();
+    model.set_user_input(0, 3, 2, "=A1/2".to_string()).unwrap();
+    model
+        .set_user_input(0, 4, 2, "=100/A2".to_string())
+        .unwrap();
 
     model.evaluate();
 
@@ -235,54 +267,54 @@ fn test_some_complex_examples() {
     // $3.00 / 2 = $1.50
     model._set("A1", "$3.00");
     model._set("A2", "2");
-    model.set_user_input(0, 3, 1, "=A1/A2".to_string());
+    model.set_user_input(0, 3, 1, "=A1/A2".to_string()).unwrap();
 
     // $3 / 2 = $1
     model._set("B1", "$3");
     model._set("B2", "2");
-    model.set_user_input(0, 3, 2, "=B1/B2".to_string());
+    model.set_user_input(0, 3, 2, "=B1/B2".to_string()).unwrap();
 
     // $5.00 * 25% = 25% * $5.00 = $1.25
     model._set("C1", "$5.00");
     model._set("C2", "25%");
-    model.set_user_input(0, 3, 3, "=C1*C2".to_string());
-    model.set_user_input(0, 4, 3, "=C2*C1".to_string());
+    model.set_user_input(0, 3, 3, "=C1*C2".to_string()).unwrap();
+    model.set_user_input(0, 4, 3, "=C2*C1".to_string()).unwrap();
 
     // $5 * 75% = 75% * $5 = $1
     model._set("D1", "$5");
     model._set("D2", "75%");
-    model.set_user_input(0, 3, 4, "=D1*D2".to_string());
-    model.set_user_input(0, 4, 4, "=D2*D1".to_string());
+    model.set_user_input(0, 3, 4, "=D1*D2".to_string()).unwrap();
+    model.set_user_input(0, 4, 4, "=D2*D1".to_string()).unwrap();
 
     // $10 + $9.99 = $9.99 + $10 = $19.99
     model._set("E1", "$10");
     model._set("E2", "$9.99");
-    model.set_user_input(0, 3, 5, "=E1+E2".to_string());
-    model.set_user_input(0, 4, 5, "=E2+E1".to_string());
+    model.set_user_input(0, 3, 5, "=E1+E2".to_string()).unwrap();
+    model.set_user_input(0, 4, 5, "=E2+E1".to_string()).unwrap();
 
     // $2 * 2 = 2 * $2 = $4
     model._set("F1", "$2");
     model._set("F2", "2");
-    model.set_user_input(0, 3, 6, "=F1*F2".to_string());
-    model.set_user_input(0, 4, 6, "=F2*F1".to_string());
+    model.set_user_input(0, 3, 6, "=F1*F2".to_string()).unwrap();
+    model.set_user_input(0, 4, 6, "=F2*F1".to_string()).unwrap();
 
     // $2.50 * 2 = 2 * $2.50 = $5.00
     model._set("G1", "$2.50");
     model._set("G2", "2");
-    model.set_user_input(0, 3, 7, "=G1*G2".to_string());
-    model.set_user_input(0, 4, 7, "=G2*G1".to_string());
+    model.set_user_input(0, 3, 7, "=G1*G2".to_string()).unwrap();
+    model.set_user_input(0, 4, 7, "=G2*G1".to_string()).unwrap();
 
     // $2 * 2.5 = 2.5 * $2 = $5
     model._set("H1", "$2");
     model._set("H2", "2.5");
-    model.set_user_input(0, 3, 8, "=H1*H2".to_string());
-    model.set_user_input(0, 4, 8, "=H2*H1".to_string());
+    model.set_user_input(0, 3, 8, "=H1*H2".to_string()).unwrap();
+    model.set_user_input(0, 4, 8, "=H2*H1".to_string()).unwrap();
 
     // 10% * 1,000 = 1,000 * 10% = 100
     model._set("I1", "10%");
     model._set("I2", "1,000");
-    model.set_user_input(0, 3, 9, "=I1*I2".to_string());
-    model.set_user_input(0, 4, 9, "=I2*I1".to_string());
+    model.set_user_input(0, 3, 9, "=I1*I2".to_string()).unwrap();
+    model.set_user_input(0, 4, 9, "=I2*I1".to_string()).unwrap();
 
     model.evaluate();
 
@@ -320,9 +352,15 @@ fn test_financial_functions() {
     model._set("A3", "10");
     model._set("A4", "$10,000");
 
-    model.set_user_input(0, 5, 1, "=PMT(A2/12,A3,A4)".to_string());
-    model.set_user_input(0, 6, 1, "=PMT(A2/12,A3,A4,,1)".to_string());
-    model.set_user_input(0, 7, 1, "=PMT(0.2, 3, -200)".to_string());
+    model
+        .set_user_input(0, 5, 1, "=PMT(A2/12,A3,A4)".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 6, 1, "=PMT(A2/12,A3,A4,,1)".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 7, 1, "=PMT(0.2, 3, -200)".to_string())
+        .unwrap();
 
     model.evaluate();
 
@@ -339,9 +377,15 @@ fn test_sum_function() {
     model._set("A1", "$100");
     model._set("A2", "$300");
 
-    model.set_user_input(0, 1, 2, "=SUM(A:A)".to_string());
-    model.set_user_input(0, 2, 2, "=SUM(A1:A2)".to_string());
-    model.set_user_input(0, 3, 2, "=SUM(A1, A2, A3)".to_string());
+    model
+        .set_user_input(0, 1, 2, "=SUM(A:A)".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 2, 2, "=SUM(A1:A2)".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 3, 2, "=SUM(A1, A2, A3)".to_string())
+        .unwrap();
 
     model.evaluate();
 
@@ -353,7 +397,7 @@ fn test_sum_function() {
 #[test]
 fn test_number() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 1, 1, "3".to_string());
+    model.set_user_input(0, 1, 1, "3".to_string()).unwrap();
 
     model.evaluate();
 
@@ -367,7 +411,9 @@ fn test_number() {
 #[test]
 fn test_currencies_eur_prefix() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 1, 1, "€100.348".to_string());
+    model
+        .set_user_input(0, 1, 1, "€100.348".to_string())
+        .unwrap();
 
     model.evaluate();
 
@@ -381,19 +427,27 @@ fn test_currencies_eur_prefix() {
 #[test]
 fn test_currencies_eur_suffix() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 1, 1, "100.348€".to_string());
-    model.set_user_input(0, 2, 1, "25€".to_string());
+    model
+        .set_user_input(0, 1, 1, "100.348€".to_string())
+        .unwrap();
+    model.set_user_input(0, 2, 1, "25€".to_string()).unwrap();
 
     // negatives
-    model.set_user_input(0, 1, 2, "-123.348€".to_string());
-    model.set_user_input(0, 2, 2, "-42€".to_string());
+    model
+        .set_user_input(0, 1, 2, "-123.348€".to_string())
+        .unwrap();
+    model.set_user_input(0, 2, 2, "-42€".to_string()).unwrap();
 
     // with a space
-    model.set_user_input(0, 1, 3, "101.348 €".to_string());
-    model.set_user_input(0, 2, 3, "26 €".to_string());
+    model
+        .set_user_input(0, 1, 3, "101.348 €".to_string())
+        .unwrap();
+    model.set_user_input(0, 2, 3, "26 €".to_string()).unwrap();
 
-    model.set_user_input(0, 1, 4, "-12.348 €".to_string());
-    model.set_user_input(0, 2, 4, "-45 €".to_string());
+    model
+        .set_user_input(0, 1, 4, "-12.348 €".to_string())
+        .unwrap();
+    model.set_user_input(0, 2, 4, "-45 €".to_string()).unwrap();
 
     model.evaluate();
 
@@ -449,9 +503,15 @@ fn test_sum_function_eur() {
     model._set("A1", "€100");
     model._set("A2", "€300");
 
-    model.set_user_input(0, 1, 2, "=SUM(A:A)".to_string());
-    model.set_user_input(0, 2, 2, "=SUM(A1:A2)".to_string());
-    model.set_user_input(0, 3, 2, "=SUM(A1, A2, A3)".to_string());
+    model
+        .set_user_input(0, 1, 2, "=SUM(A:A)".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 2, 2, "=SUM(A1:A2)".to_string())
+        .unwrap();
+    model
+        .set_user_input(0, 3, 2, "=SUM(A1, A2, A3)".to_string())
+        .unwrap();
 
     model.evaluate();
 
@@ -463,7 +523,9 @@ fn test_sum_function_eur() {
 #[test]
 fn input_dates() {
     let mut model = new_empty_model();
-    model.set_user_input(0, 1, 1, "3/4/2025".to_string());
+    model
+        .set_user_input(0, 1, 1, "3/4/2025".to_string())
+        .unwrap();
 
     model.evaluate();
 
@@ -474,7 +536,9 @@ fn input_dates() {
     );
 
     // further date assignments do not change the format
-    model.set_user_input(0, 1, 1, "08-08-2028".to_string());
+    model
+        .set_user_input(0, 1, 1, "08-08-2028".to_string())
+        .unwrap();
     model.evaluate();
     assert_eq!(model._get_text("A1"), "8/8/2028");
 }

base/src/test/test_sheet_markup.rs

@@ -14,14 +14,14 @@ fn test_sheet_markup() {
     model._set("A4", "Total");
     model._set("B4", "=SUM(B2:B3)");
 
-    let mut style = model.get_style_for_cell(0, 1, 1);
+    let mut style = model.get_style_for_cell(0, 1, 1).unwrap();
     style.font.b = true;
     model.set_cell_style(0, 1, 1, &style).unwrap();
     model.set_cell_style(0, 1, 2, &style).unwrap();
     model.set_cell_style(0, 4, 1, &style).unwrap();
 
     assert_eq!(
-        model.sheet_markup(0),
+        model.get_sheet_markup(0),
         Ok("**Item**|**Cost**\nRent|$600\nElectricity|$200\n**Total**|=SUM(B2:B3)".to_string()),
     )
 }

base/src/test/test_sheets.rs

@@ -138,14 +138,14 @@ fn test_insert_sheet() {
 
     // Insert the sheet at the end and check the formula
     assert!(model.insert_sheet("Bacchus", 1, None).is_ok());
-    model.set_user_input(1, 3, 1, "42".to_string());
+    model.set_user_input(1, 3, 1, "42".to_string()).unwrap();
     model.evaluate();
     assert_eq!(model._get_text("A1"), "42");
     assert_eq!(model._get_text("A2"), "#REF!");
 
     // Insert a sheet in between the other two
     assert!(model.insert_sheet("Dionysus", 1, None).is_ok());
-    model.set_user_input(1, 3, 1, "111".to_string());
+    model.set_user_input(1, 3, 1, "111".to_string()).unwrap();
     model.evaluate();
     assert_eq!(model._get_text("A1"), "42");
     assert_eq!(model._get_text("A2"), "111");
@@ -176,7 +176,7 @@ fn test_rename_sheet() {
     let mut model = new_empty_model();
     model.new_sheet();
     model._set("A1", "=NewSheet!A3");
-    model.set_user_input(1, 3, 1, "25".to_string());
+    model.set_user_input(1, 3, 1, "25".to_string()).unwrap();
     model.evaluate();
     assert_eq!(model._get_text("A1"), "#REF!");
     assert!(model.rename_sheet("Sheet2", "NewSheet").is_ok());
@@ -189,7 +189,7 @@ fn test_rename_sheet_by_index() {
     let mut model = new_empty_model();
     model.new_sheet();
     model._set("A1", "=NewSheet!A1");
-    model.set_user_input(1, 1, 1, "25".to_string());
+    model.set_user_input(1, 1, 1, "25".to_string()).unwrap();
     model.evaluate();
     assert_eq!(model._get_text("A1"), "#REF!");
     assert!(model.rename_sheet_by_index(1, "NewSheet").is_ok());
@@ -236,3 +236,11 @@ fn test_delete_sheet_by_index() {
     assert_eq!(model.workbook.get_worksheet_names(), ["Sheet2"]);
     assert_eq!(model._get_text("Sheet2!A1"), "#REF!");
 }
+
+#[test]
+fn delete_sheet_error() {
+    let mut model = new_empty_model();
+    model.new_sheet();
+    assert!(model.delete_sheet(2).is_err());
+    assert!(model.delete_sheet(1).is_ok());
+}

base/src/test/test_styles.rs

@@ -7,10 +7,10 @@ use crate::types::Style;
 fn test_model_set_cells_with_values_styles() {
     let mut model = new_empty_model();
     // Inputs
-    model.set_user_input(0, 1, 1, "21".to_string()); // A1
-    model.set_user_input(0, 2, 1, "42".to_string()); // A2
+    model.set_user_input(0, 1, 1, "21".to_string()).unwrap(); // A1
+    model.set_user_input(0, 2, 1, "42".to_string()).unwrap(); // A2
 
-    let style_base = model.get_style_for_cell(0, 1, 1);
+    let style_base = model.get_style_for_cell(0, 1, 1).unwrap();
     let mut style = style_base.clone();
     style.font.b = true;
     style.num_fmt = "#,##0.00".to_string();
@@ -19,7 +19,7 @@ fn test_model_set_cells_with_values_styles() {
     let mut style = style_base;
     style.num_fmt = "#,##0.00".to_string();
     assert!(model.set_cell_style(0, 2, 1, &style).is_ok());
-    let style: Style = model.get_style_for_cell(0, 2, 1);
+    let style: Style = model.get_style_for_cell(0, 2, 1).unwrap();
     assert_eq!(style.num_fmt, "#,##0.00".to_string());
 }
 
@@ -27,21 +27,21 @@ fn test_model_set_cells_with_values_styles() {
 fn test_named_styles() {
     let mut model = new_empty_model();
     model._set("A1", "42");
-    let mut style = model.get_style_for_cell(0, 1, 1);
+    let mut style = model.get_style_for_cell(0, 1, 1).unwrap();
     style.font.b = true;
     assert!(model.set_cell_style(0, 1, 1, &style).is_ok());
-    let bold_style_index = model.get_cell_style_index(0, 1, 1);
+    let bold_style_index = model.get_cell_style_index(0, 1, 1).unwrap();
     let e = model
         .workbook
         .styles
         .add_named_cell_style("bold", bold_style_index);
     assert!(e.is_ok());
     model._set("A2", "420");
-    let a2_style_index = model.get_cell_style_index(0, 2, 1);
+    let a2_style_index = model.get_cell_style_index(0, 2, 1).unwrap();
     assert!(a2_style_index != bold_style_index);
     let e = model.set_cell_style_by_name(0, 2, 1, "bold");
     assert!(e.is_ok());
-    assert_eq!(model.get_cell_style_index(0, 2, 1), bold_style_index);
+    assert_eq!(model.get_cell_style_index(0, 2, 1), Ok(bold_style_index));
 }
 
 #[test]
@@ -49,7 +49,7 @@ fn test_create_named_style() {
     let mut model = new_empty_model();
     model._set("A1", "42");
 
-    let mut style = model.get_style_for_cell(0, 1, 1);
+    let mut style = model.get_style_for_cell(0, 1, 1).unwrap();
     assert!(!style.font.b);
 
     style.font.b = true;
@@ -59,6 +59,6 @@ fn test_create_named_style() {
     let e = model.set_cell_style_by_name(0, 1, 1, "bold");
     assert!(e.is_ok());
 
-    let style = model.get_style_for_cell(0, 1, 1);
+    let style = model.get_style_for_cell(0, 1, 1).unwrap();
     assert!(style.font.b);
 }

base/src/test/test_types.rs

@@ -0,0 +1,24 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::types::{Alignment, HorizontalAlignment, VerticalAlignment};
+
+#[test]
+fn alignment_default() {
+    let alignment = Alignment::default();
+    assert_eq!(
+        alignment,
+        Alignment {
+            horizontal: HorizontalAlignment::General,
+            vertical: VerticalAlignment::Bottom,
+            wrap_text: false
+        }
+    );
+
+    let s = serde_json::to_string(&alignment).unwrap();
+    // defaults stringifies as an empty object
+    assert_eq!(s, "{}");
+
+    let a: Alignment = serde_json::from_str("{}").unwrap();
+
+    assert_eq!(a, alignment)
+}

base/src/test/test_workbook.rs

@@ -1,14 +1,14 @@
 #![allow(clippy::unwrap_used)]
 
-use crate::{test::util::new_empty_model, types::SheetInfo};
+use crate::{test::util::new_empty_model, types::SheetProperties};
 
 #[test]
 fn workbook_worksheets_info() {
     let model = new_empty_model();
-    let sheets_info = model.workbook.get_worksheets_info();
+    let sheets_info = model.get_worksheets_properties();
     assert_eq!(
         sheets_info[0],
-        SheetInfo {
+        SheetProperties {
             name: "Sheet1".to_string(),
             state: "visible".to_string(),
             sheet_id: 1,

base/src/test/test_worksheet.rs

@@ -39,7 +39,7 @@ fn test_worksheet_dimension_single_cell() {
 fn test_worksheet_dimension_single_cell_set_empty() {
     let mut model = new_empty_model();
     model._set("W11", "1");
-    model.set_cell_empty(0, 11, 23).unwrap();
+    model.cell_clear_contents(0, 11, 23).unwrap();
     assert_eq!(
         model.workbook.worksheet(0).unwrap().dimension(),
         WorksheetDimension {
@@ -55,7 +55,7 @@ fn test_worksheet_dimension_single_cell_set_empty() {
 fn test_worksheet_dimension_single_cell_deleted() {
     let mut model = new_empty_model();
     model._set("W11", "1");
-    model.delete_cell(0, 11, 23).unwrap();
+    model.cell_clear_all(0, 11, 23).unwrap();
     assert_eq!(
         model.workbook.worksheet(0).unwrap().dimension(),
         WorksheetDimension {
@@ -75,7 +75,7 @@ fn test_worksheet_dimension_multiple_cells() {
     model._set("AA17", "1");
     model._set("G17", "1");
     model._set("B19", "1");
-    model.delete_cell(0, 11, 23).unwrap();
+    model.cell_clear_all(0, 11, 23).unwrap();
     assert_eq!(
         model.workbook.worksheet(0).unwrap().dimension(),
         WorksheetDimension {
@@ -100,7 +100,9 @@ fn test_worksheet_dimension_progressive() {
         }
     );
 
-    model.set_user_input(0, 30, 50, "Hello World".to_string());
+    model
+        .set_user_input(0, 30, 50, "Hello World".to_string())
+        .unwrap();
     assert_eq!(
         model.workbook.worksheet(0).unwrap().dimension(),
         WorksheetDimension {
@@ -111,7 +113,9 @@ fn test_worksheet_dimension_progressive() {
         }
     );
 
-    model.set_user_input(0, 10, 15, "Hello World".to_string());
+    model
+        .set_user_input(0, 10, 15, "Hello World".to_string())
+        .unwrap();
     assert_eq!(
         model.workbook.worksheet(0).unwrap().dimension(),
         WorksheetDimension {
@@ -122,7 +126,9 @@ fn test_worksheet_dimension_progressive() {
         }
     );
 
-    model.set_user_input(0, 5, 25, "Hello World".to_string());
+    model
+        .set_user_input(0, 5, 25, "Hello World".to_string())
+        .unwrap();
     assert_eq!(
         model.workbook.worksheet(0).unwrap().dimension(),
         WorksheetDimension {
@@ -133,7 +139,9 @@ fn test_worksheet_dimension_progressive() {
         }
     );
 
-    model.set_user_input(0, 10, 250, "Hello World".to_string());
+    model
+        .set_user_input(0, 10, 250, "Hello World".to_string())
+        .unwrap();
     assert_eq!(
         model.workbook.worksheet(0).unwrap().dimension(),
         WorksheetDimension {
@@ -162,12 +170,14 @@ fn test_worksheet_navigate_to_edge_in_direction() {
     for (row_index, row) in inline_spreadsheet.into_iter().enumerate() {
         for (column_index, value) in row.into_iter().enumerate() {
             if value != 0 {
-                model.update_cell_with_number(
-                    0,
-                    (row_index as i32) + 1,
-                    (column_index as i32) + 1,
-                    value.into(),
-                );
+                model
+                    .update_cell_with_number(
+                        0,
+                        (row_index as i32) + 1,
+                        (column_index as i32) + 1,
+                        value.into(),
+                    )
+                    .unwrap();
             }
         }
     }

base/src/test/user_model/mod.rs

@@ -0,0 +1,20 @@
+mod test_add_delete_sheets;
+mod test_autofill_columns;
+mod test_autofill_rows;
+mod test_border;
+mod test_clear_cells;
+mod test_diff_queue;
+mod test_evaluation;
+mod test_general;
+mod test_grid_lines;
+mod test_keyboard_navigation;
+mod test_on_area_selection;
+mod test_on_expand_selected_range;
+mod test_on_paste_styles;
+mod test_rename_sheet;
+mod test_row_column;
+mod test_styles;
+mod test_to_from_bytes;
+mod test_undo_redo;
+mod test_view;
+mod test_window_size;

base/src/test/user_model/test_add_delete_sheets.rs

@@ -0,0 +1,96 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::{constants::DEFAULT_COLUMN_WIDTH, UserModel};
+
+#[test]
+fn add_undo_redo() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model.new_sheet();
+    model.set_user_input(1, 1, 1, "=1 + 1").unwrap();
+    model.set_user_input(1, 1, 2, "=A1*3").unwrap();
+    model
+        .set_column_width(1, 5, 5.0 * DEFAULT_COLUMN_WIDTH)
+        .unwrap();
+    model.new_sheet();
+    model.set_user_input(2, 1, 1, "=Sheet2!B1").unwrap();
+
+    model.undo().unwrap();
+    model.undo().unwrap();
+
+    assert!(model.get_formatted_cell_value(2, 1, 1).is_err());
+
+    model.redo().unwrap();
+    model.redo().unwrap();
+
+    assert_eq!(model.get_formatted_cell_value(2, 1, 1), Ok("6".to_string()));
+
+    model.delete_sheet(1).unwrap();
+
+    assert!(!model.can_undo());
+    assert!(!model.can_redo());
+}
+
+#[test]
+fn set_sheet_color() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model.set_sheet_color(0, "#343434").unwrap();
+    let worksheets_properties = model.get_worksheets_properties();
+    assert_eq!(worksheets_properties.len(), 1);
+    assert_eq!(worksheets_properties[0].color, Some("#343434".to_owned()));
+    model.undo().unwrap();
+    assert_eq!(model.get_worksheets_properties()[0].color, None);
+
+    model.redo().unwrap();
+    assert_eq!(
+        model.get_worksheets_properties()[0].color,
+        Some("#343434".to_owned())
+    );
+    // changes the color if there is one
+    model.set_sheet_color(0, "#2534FF").unwrap();
+    assert_eq!(
+        model.get_worksheets_properties()[0].color,
+        Some("#2534FF".to_owned())
+    );
+    // Setting it back to none
+    model.set_sheet_color(0, "").unwrap();
+    assert_eq!(model.get_worksheets_properties()[0].color, None);
+}
+
+#[test]
+fn new_sheet_propagates() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model.new_sheet();
+
+    let send_queue = model.flush_send_queue();
+
+    let mut model2 = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model2.apply_external_diffs(&send_queue).unwrap();
+    let worksheets_properties = model2.get_worksheets_properties();
+    assert_eq!(worksheets_properties.len(), 2);
+}
+
+#[test]
+fn delete_sheet_propagates() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model.new_sheet();
+    model.delete_sheet(0).unwrap();
+
+    let send_queue = model.flush_send_queue();
+
+    let mut model2 = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model2.apply_external_diffs(&send_queue).unwrap();
+    let sheets_info = model2.get_worksheets_properties();
+    assert_eq!(sheets_info.len(), 1);
+}
+
+#[test]
+fn delete_last_sheet() {
+    // Deleting the last sheet, selects the previous
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model.new_sheet();
+    model.new_sheet();
+    model.set_selected_sheet(2).unwrap();
+    model.delete_sheet(2).unwrap();
+
+    assert_eq!(model.get_selected_sheet(), 1);
+}

base/src/test/user_model/test_autofill_columns.rs

@@ -0,0 +1,404 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::constants::{LAST_COLUMN, LAST_ROW};
+use crate::expressions::types::Area;
+use crate::test::util::new_empty_model;
+use crate::UserModel;
+
+#[test]
+fn basic_tests() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // This is cell A3
+    model.set_user_input(0, 3, 1, "alpha").unwrap();
+    // We autofill from A3 to C3
+    model
+        .auto_fill_columns(
+            &Area {
+                sheet: 0,
+                row: 3,
+                column: 1,
+                width: 1,
+                height: 1,
+            },
+            5,
+        )
+        .unwrap();
+    // B3
+    assert_eq!(
+        model.get_formatted_cell_value(0, 3, 2),
+        Ok("alpha".to_string())
+    );
+    // C3
+    assert_eq!(
+        model.get_formatted_cell_value(0, 3, 3),
+        Ok("alpha".to_string())
+    );
+}
+
+#[test]
+fn one_cell_right() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.set_user_input(0, 1, 1, "23").unwrap();
+    model
+        .auto_fill_columns(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: 1,
+                width: 1,
+                height: 1,
+            },
+            2,
+        )
+        .unwrap();
+    // B1
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 2),
+        Ok("23".to_string())
+    );
+}
+
+#[test]
+fn alpha_beta_gamma() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // cells A1:B3
+    model.set_user_input(0, 1, 1, "Alpher").unwrap(); // A1
+    model.set_user_input(0, 1, 2, "Bethe").unwrap(); // B1
+    model.set_user_input(0, 1, 3, "Gamow").unwrap(); // C1
+    model.set_user_input(0, 2, 1, "=A1").unwrap(); // A2
+    model.set_user_input(0, 2, 2, "=B1").unwrap(); // B2
+    model.set_user_input(0, 2, 3, "=C1").unwrap(); // C2
+
+    // We autofill from A1:C2 to I2
+    model
+        .auto_fill_columns(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: 1,
+                width: 3,
+                height: 2,
+            },
+            9,
+        )
+        .unwrap();
+
+    // D1
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 4),
+        Ok("Alpher".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 5),
+        Ok("Bethe".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 6),
+        Ok("Gamow".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 7),
+        Ok("Alpher".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 8),
+        Ok("Bethe".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 9),
+        Ok("Gamow".to_string())
+    );
+
+    assert_eq!(
+        model.get_formatted_cell_value(0, 2, 4),
+        Ok("Alpher".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 2, 5),
+        Ok("Bethe".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 2, 6),
+        Ok("Gamow".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 2, 7),
+        Ok("Alpher".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 2, 8),
+        Ok("Bethe".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 2, 9),
+        Ok("Gamow".to_string())
+    );
+
+    assert_eq!(model.get_cell_content(0, 2, 4), Ok("=D1".to_string()));
+}
+
+#[test]
+fn styles() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // cells A1:C1
+    model.set_user_input(0, 1, 1, "Alpher").unwrap();
+    model.set_user_input(0, 2, 1, "Bethe").unwrap();
+    model.set_user_input(0, 3, 1, "Gamow").unwrap();
+
+    let b1 = Area {
+        sheet: 0,
+        row: 1,
+        column: 2,
+        width: 1,
+        height: 1,
+    };
+
+    let c1 = Area {
+        sheet: 0,
+        row: 1,
+        column: 3,
+        width: 1,
+        height: 1,
+    };
+
+    model.update_range_style(&b1, "font.i", "true").unwrap();
+    model
+        .update_range_style(&c1, "fill.bg_color", "#334455")
+        .unwrap();
+
+    model
+        .auto_fill_columns(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: 1,
+                width: 3,
+                height: 1,
+            },
+            9,
+        )
+        .unwrap();
+
+    // Check that cell E1 has B1 style
+    let style = model.get_cell_style(0, 1, 5).unwrap();
+    assert!(style.font.i);
+    // A6 would have the style of A3
+    let style = model.get_cell_style(0, 1, 6).unwrap();
+    assert_eq!(style.fill.bg_color, Some("#334455".to_string()));
+
+    model.undo().unwrap();
+
+    assert_eq!(model.get_cell_content(0, 1, 4), Ok("".to_string()));
+    // Check that cell A5 has A2 style
+    let style = model.get_cell_style(0, 1, 5).unwrap();
+    assert!(!style.font.i);
+    // A6 would have the style of A3
+    let style = model.get_cell_style(0, 1, 6).unwrap();
+    assert_eq!(style.fill.bg_color, None);
+
+    model.redo().unwrap();
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 4),
+        Ok("Alpher".to_string())
+    );
+    // Check that cell A5 has A2 style
+    let style = model.get_cell_style(0, 1, 5).unwrap();
+    assert!(style.font.i);
+    // A6 would have the style of A3
+    let style = model.get_cell_style(0, 1, 6).unwrap();
+    assert_eq!(style.fill.bg_color, Some("#334455".to_string()));
+}
+
+#[test]
+fn left() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // cells A10:A12
+    model.set_user_input(0, 1, 10, "Alpher").unwrap();
+    model.set_user_input(0, 1, 11, "Bethe").unwrap();
+    model.set_user_input(0, 1, 12, "Gamow").unwrap();
+
+    // We fill upwards to row 5
+    model
+        .auto_fill_columns(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: 10,
+                width: 3,
+                height: 1,
+            },
+            5,
+        )
+        .unwrap();
+
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 9),
+        Ok("Gamow".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 8),
+        Ok("Bethe".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 7),
+        Ok("Alpher".to_string())
+    );
+}
+
+#[test]
+fn left_4() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // cells A10:A13
+    model.set_user_input(0, 1, 10, "Margaret Burbidge").unwrap();
+    model.set_user_input(0, 1, 11, "Geoffrey Burbidge").unwrap();
+    model.set_user_input(0, 1, 12, "Willy Fowler").unwrap();
+    model.set_user_input(0, 1, 13, "Fred Hoyle").unwrap();
+
+    // We fill left to row 5
+    model
+        .auto_fill_columns(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: 10,
+                width: 4,
+                height: 1,
+            },
+            5,
+        )
+        .unwrap();
+
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 9),
+        Ok("Fred Hoyle".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 8),
+        Ok("Willy Fowler".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 5),
+        Ok("Fred Hoyle".to_string())
+    );
+}
+
+#[test]
+fn errors() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+
+    model.set_user_input(0, 1, 4, "Margaret Burbidge").unwrap();
+
+    // Invalid sheet
+    assert_eq!(
+        model.auto_fill_columns(
+            &Area {
+                sheet: 3,
+                row: 1,
+                column: 4,
+                width: 1,
+                height: 1,
+            },
+            10,
+        ),
+        Err("Invalid worksheet index: '3'".to_string())
+    );
+
+    // invalid column
+    assert_eq!(
+        model.auto_fill_columns(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: -1,
+                width: 1,
+                height: 1,
+            },
+            10,
+        ),
+        Err("Invalid column: '-1'".to_string())
+    );
+
+    // invalid column
+    assert_eq!(
+        model.auto_fill_columns(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: LAST_COLUMN - 1,
+                width: 10,
+                height: 1,
+            },
+            10,
+        ),
+        Err("Invalid column: '16392'".to_string())
+    );
+
+    assert_eq!(
+        model.auto_fill_columns(
+            &Area {
+                sheet: 0,
+                row: LAST_ROW + 1,
+                column: 1,
+                width: 10,
+                height: 1,
+            },
+            10,
+        ),
+        Err("Invalid row: '1048577'".to_string())
+    );
+
+    assert_eq!(
+        model.auto_fill_columns(
+            &Area {
+                sheet: 0,
+                row: LAST_ROW - 2,
+                column: 1,
+                width: 1,
+                height: 10,
+            },
+            10,
+        ),
+        Err("Invalid row: '1048583'".to_string())
+    );
+
+    assert_eq!(
+        model.auto_fill_columns(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: 5,
+                width: 10,
+                height: 1,
+            },
+            -10,
+        ),
+        Err("Invalid row: '-10'".to_string())
+    );
+}
+
+#[test]
+fn invalid_parameters() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.set_user_input(0, 1, 1, "23").unwrap();
+    assert_eq!(
+        model.auto_fill_columns(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: 1,
+                width: 2,
+                height: 1,
+            },
+            2,
+        ),
+        Err("Invalid parameters for autofill".to_string())
+    );
+}

base/src/test/user_model/test_autofill_rows.rs

@@ -0,0 +1,399 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::constants::{LAST_COLUMN, LAST_ROW};
+use crate::expressions::types::Area;
+use crate::test::util::new_empty_model;
+use crate::UserModel;
+
+#[test]
+fn basic_tests() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // This is cell A3
+    model.set_user_input(0, 3, 1, "alpha").unwrap();
+    // We autofill from A3 to A5
+    model
+        .auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 3,
+                column: 1,
+                width: 1,
+                height: 1,
+            },
+            5,
+        )
+        .unwrap();
+    assert_eq!(
+        model.get_formatted_cell_value(0, 4, 1),
+        Ok("alpha".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 5, 1),
+        Ok("alpha".to_string())
+    );
+}
+
+#[test]
+fn one_cell_down() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.set_user_input(0, 1, 1, "23").unwrap();
+    model
+        .auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: 1,
+                width: 1,
+                height: 1,
+            },
+            2,
+        )
+        .unwrap();
+    assert_eq!(
+        model.get_formatted_cell_value(0, 2, 1),
+        Ok("23".to_string())
+    );
+}
+
+#[test]
+fn alpha_beta_gamma() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // cells A1:B3
+    model.set_user_input(0, 1, 1, "Alpher").unwrap();
+    model.set_user_input(0, 2, 1, "Bethe").unwrap();
+    model.set_user_input(0, 3, 1, "Gamow").unwrap();
+    model.set_user_input(0, 1, 2, "=A1").unwrap();
+    model.set_user_input(0, 2, 2, "=A2").unwrap();
+    model.set_user_input(0, 3, 2, "=A3").unwrap();
+    // We autofill from A1:B3 to A9
+    model
+        .auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: 1,
+                width: 2,
+                height: 3,
+            },
+            9,
+        )
+        .unwrap();
+
+    assert_eq!(
+        model.get_formatted_cell_value(0, 4, 1),
+        Ok("Alpher".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 5, 1),
+        Ok("Bethe".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 6, 1),
+        Ok("Gamow".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 7, 1),
+        Ok("Alpher".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 8, 1),
+        Ok("Bethe".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 9, 1),
+        Ok("Gamow".to_string())
+    );
+
+    assert_eq!(
+        model.get_formatted_cell_value(0, 4, 2),
+        Ok("Alpher".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 5, 2),
+        Ok("Bethe".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 6, 2),
+        Ok("Gamow".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 7, 2),
+        Ok("Alpher".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 8, 2),
+        Ok("Bethe".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 9, 2),
+        Ok("Gamow".to_string())
+    );
+
+    assert_eq!(model.get_cell_content(0, 4, 2), Ok("=A4".to_string()));
+}
+
+#[test]
+fn styles() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // cells A1:B3
+    model.set_user_input(0, 1, 1, "Alpher").unwrap();
+    model.set_user_input(0, 2, 1, "Bethe").unwrap();
+    model.set_user_input(0, 3, 1, "Gamow").unwrap();
+
+    let a2 = Area {
+        sheet: 0,
+        row: 2,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+
+    let a3 = Area {
+        sheet: 0,
+        row: 3,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+
+    model.update_range_style(&a2, "font.i", "true").unwrap();
+    model
+        .update_range_style(&a3, "fill.bg_color", "#334455")
+        .unwrap();
+
+    model
+        .auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: 1,
+                width: 1,
+                height: 3,
+            },
+            9,
+        )
+        .unwrap();
+
+    // Check that cell A5 has A2 style
+    let style = model.get_cell_style(0, 5, 1).unwrap();
+    assert!(style.font.i);
+    // A6 would have the style of A3
+    let style = model.get_cell_style(0, 6, 1).unwrap();
+    assert_eq!(style.fill.bg_color, Some("#334455".to_string()));
+
+    model.undo().unwrap();
+
+    assert_eq!(model.get_cell_content(0, 4, 1), Ok("".to_string()));
+    // Check that cell A5 has A2 style
+    let style = model.get_cell_style(0, 5, 1).unwrap();
+    assert!(!style.font.i);
+    // A6 would have the style of A3
+    let style = model.get_cell_style(0, 6, 1).unwrap();
+    assert_eq!(style.fill.bg_color, None);
+
+    model.redo().unwrap();
+    assert_eq!(
+        model.get_formatted_cell_value(0, 4, 1),
+        Ok("Alpher".to_string())
+    );
+    // Check that cell A5 has A2 style
+    let style = model.get_cell_style(0, 5, 1).unwrap();
+    assert!(style.font.i);
+    // A6 would have the style of A3
+    let style = model.get_cell_style(0, 6, 1).unwrap();
+    assert_eq!(style.fill.bg_color, Some("#334455".to_string()));
+}
+
+#[test]
+fn upwards() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // cells A10:A12
+    model.set_user_input(0, 10, 1, "Alpher").unwrap();
+    model.set_user_input(0, 11, 1, "Bethe").unwrap();
+    model.set_user_input(0, 12, 1, "Gamow").unwrap();
+
+    // We fill upwards to row 5
+    model
+        .auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 10,
+                column: 1,
+                width: 1,
+                height: 3,
+            },
+            5,
+        )
+        .unwrap();
+
+    assert_eq!(
+        model.get_formatted_cell_value(0, 9, 1),
+        Ok("Gamow".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 8, 1),
+        Ok("Bethe".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 7, 1),
+        Ok("Alpher".to_string())
+    );
+}
+
+#[test]
+fn upwards_4() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // cells A10:A13
+    model.set_user_input(0, 10, 1, "Margaret Burbidge").unwrap();
+    model.set_user_input(0, 11, 1, "Geoffrey Burbidge").unwrap();
+    model.set_user_input(0, 12, 1, "Willy Fowler").unwrap();
+    model.set_user_input(0, 13, 1, "Fred Hoyle").unwrap();
+
+    // We fill upwards to row 5
+    model
+        .auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 10,
+                column: 1,
+                width: 1,
+                height: 4,
+            },
+            5,
+        )
+        .unwrap();
+
+    assert_eq!(
+        model.get_formatted_cell_value(0, 9, 1),
+        Ok("Fred Hoyle".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 8, 1),
+        Ok("Willy Fowler".to_string())
+    );
+    assert_eq!(
+        model.get_formatted_cell_value(0, 5, 1),
+        Ok("Fred Hoyle".to_string())
+    );
+}
+
+#[test]
+fn errors() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // cells A10:A13
+    model.set_user_input(0, 4, 1, "Margaret Burbidge").unwrap();
+
+    // Invalid sheet
+    assert_eq!(
+        model.auto_fill_rows(
+            &Area {
+                sheet: 3,
+                row: 4,
+                column: 1,
+                width: 1,
+                height: 1,
+            },
+            10,
+        ),
+        Err("Invalid worksheet index: '3'".to_string())
+    );
+
+    // invalid row
+    assert_eq!(
+        model.auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: -1,
+                column: 1,
+                width: 1,
+                height: 1,
+            },
+            10,
+        ),
+        Err("Invalid row: '-1'".to_string())
+    );
+
+    // invalid row
+    assert_eq!(
+        model.auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: LAST_ROW - 1,
+                column: 1,
+                width: 1,
+                height: 10,
+            },
+            10,
+        ),
+        Err("Invalid row: '1048584'".to_string())
+    );
+
+    assert_eq!(
+        model.auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: LAST_COLUMN + 1,
+                width: 1,
+                height: 10,
+            },
+            10,
+        ),
+        Err("Invalid column: '16385'".to_string())
+    );
+
+    assert_eq!(
+        model.auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: LAST_COLUMN - 2,
+                width: 10,
+                height: 1,
+            },
+            10,
+        ),
+        Err("Invalid column: '16391'".to_string())
+    );
+
+    assert_eq!(
+        model.auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 5,
+                column: 1,
+                width: 1,
+                height: 10,
+            },
+            -10,
+        ),
+        Err("Invalid row: '-10'".to_string())
+    );
+}
+
+#[test]
+fn invalid_parameters() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.set_user_input(0, 1, 1, "23").unwrap();
+    assert_eq!(
+        model.auto_fill_rows(
+            &Area {
+                sheet: 0,
+                row: 1,
+                column: 1,
+                width: 1,
+                height: 2,
+            },
+            2,
+        ),
+        Err("Invalid parameters for autofill".to_string())
+    );
+}

base/src/test/user_model/test_border.rs

@@ -0,0 +1,416 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::{
+    expressions::{types::Area, utils::number_to_column},
+    types::{Border, BorderItem, BorderStyle},
+    BorderArea, UserModel,
+};
+
+#[test]
+fn borders_all() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    // We set an outer border in cells F5:H9
+    let range = &Area {
+        sheet: 0,
+        row: 5,
+        column: 6,
+        width: 3,
+        height: 4,
+    };
+    assert_eq!(number_to_column(6).unwrap(), "F");
+    assert_eq!(number_to_column(8).unwrap(), "H");
+    // ATM we don't have a way to create the object from Rust, that's ok.
+    let border_area: BorderArea = serde_json::from_str(
+        r##"{
+      "item": {
+        "style": "thin",
+        "color": "#FF5566"
+      },
+      "type": "All"
+    }"##,
+    )
+    .unwrap();
+    model.set_area_with_border(range, &border_area).unwrap();
+    for row in 5..9 {
+        for column in 6..9 {
+            let style = model.get_cell_style(0, row, column).unwrap();
+            let border_item = BorderItem {
+                style: BorderStyle::Thin,
+                color: Some("#FF5566".to_string()),
+            };
+            let expected_border = Border {
+                diagonal_up: false,
+                diagonal_down: false,
+                left: Some(border_item.clone()),
+                right: Some(border_item.clone()),
+                top: Some(border_item.clone()),
+                bottom: Some(border_item.clone()),
+                diagonal: None,
+            };
+            assert_eq!(style.border, expected_border);
+        }
+    }
+
+    // Lets remove all of them:
+    let border_area: BorderArea = serde_json::from_str(
+        r##"{
+      "item": {
+        "style": "thin",
+        "color": "#FF5566"
+      },
+      "type": "None"
+    }"##,
+    )
+    .unwrap();
+    model.set_area_with_border(range, &border_area).unwrap();
+    for row in 5..9 {
+        for column in 6..9 {
+            let style = model.get_cell_style(0, row, column).unwrap();
+            let expected_border = Border {
+                diagonal_up: false,
+                diagonal_down: false,
+                left: None,
+                right: None,
+                top: None,
+                bottom: None,
+                diagonal: None,
+            };
+            assert_eq!(style.border, expected_border);
+        }
+    }
+}
+
+#[test]
+fn borders_inner() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    // We set an outer border in cells F5:H9
+    let range = &Area {
+        sheet: 0,
+        row: 5,
+        column: 6,
+        width: 3,
+        height: 4,
+    };
+    assert_eq!(number_to_column(6).unwrap(), "F");
+    assert_eq!(number_to_column(8).unwrap(), "H");
+    // ATM we don't have a way to create the object from Rust, that's ok.
+    let border_area: BorderArea = serde_json::from_str(
+        r##"{
+      "item": {
+        "style": "thin",
+        "color": "#FF5566"
+      },
+      "type": "Inner"
+    }"##,
+    )
+    .unwrap();
+    model.set_area_with_border(range, &border_area).unwrap();
+    // The inner part all have borders
+    for row in 6..8 {
+        for column in 7..8 {
+            let style = model.get_cell_style(0, row, column).unwrap();
+            let border_item = BorderItem {
+                style: BorderStyle::Thin,
+                color: Some("#FF5566".to_string()),
+            };
+            let expected_border = Border {
+                diagonal_up: false,
+                diagonal_down: false,
+                left: Some(border_item.clone()),
+                right: Some(border_item.clone()),
+                top: Some(border_item.clone()),
+                bottom: Some(border_item.clone()),
+                diagonal: None,
+            };
+            assert_eq!(style.border, expected_border);
+        }
+    }
+    // F5 has border only left and bottom
+    {
+        // We check the border on F5
+        let style = model.get_cell_style(0, 5, 6).unwrap();
+        let border_item = BorderItem {
+            style: BorderStyle::Thin,
+            color: Some("#FF5566".to_string()),
+        };
+        // It should be right and bottom
+        let expected_border = Border {
+            diagonal_up: false,
+            diagonal_down: false,
+            left: None,
+            right: Some(border_item.clone()),
+            top: None,
+            bottom: Some(border_item),
+            diagonal: None,
+        };
+        assert_eq!(style.border, expected_border);
+    }
+    {
+        // Then let's try the bottom-right border
+        let style = model.get_cell_style(0, 8, 8).unwrap();
+        let border_item = BorderItem {
+            style: BorderStyle::Thin,
+            color: Some("#FF5566".to_string()),
+        };
+        // It should be only left and top
+        let expected_border = Border {
+            diagonal_up: false,
+            diagonal_down: false,
+            left: Some(border_item.clone()),
+            right: None,
+            top: Some(border_item.clone()),
+            bottom: None,
+            diagonal: None,
+        };
+        assert_eq!(style.border, expected_border);
+    }
+}
+
+#[test]
+fn borders_outer() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    // We set an outer border in cells F5:H9
+    let range = &Area {
+        sheet: 0,
+        row: 5,
+        column: 6,
+        width: 3,
+        height: 4,
+    };
+    assert_eq!(number_to_column(6).unwrap(), "F");
+    assert_eq!(number_to_column(8).unwrap(), "H");
+    // ATM we don't have a way to create the object from Rust, that's ok.
+    let border_area: BorderArea = serde_json::from_str(
+        r##"{
+      "item": {
+        "style": "thin",
+        "color": "#FF5566"
+      },
+      "type": "Outer"
+    }"##,
+    )
+    .unwrap();
+    model.set_area_with_border(range, &border_area).unwrap();
+    {
+        // We check the border on F5
+        let style = model.get_cell_style(0, 5, 6).unwrap();
+        let border_item = BorderItem {
+            style: BorderStyle::Thin,
+            color: Some("#FF5566".to_string()),
+        };
+        // It should be only left and top
+        let expected_border = Border {
+            diagonal_up: false,
+            diagonal_down: false,
+            left: Some(border_item.clone()),
+            right: None,
+            top: Some(border_item),
+            bottom: None,
+            diagonal: None,
+        };
+        assert_eq!(style.border, expected_border);
+    }
+    {
+        // Then let's try the bottom-right border
+        let style = model.get_cell_style(0, 8, 8).unwrap();
+        let border_item = BorderItem {
+            style: BorderStyle::Thin,
+            color: Some("#FF5566".to_string()),
+        };
+        // It should be only left and top
+        let expected_border = Border {
+            diagonal_up: false,
+            diagonal_down: false,
+            left: None,
+            right: Some(border_item.clone()),
+            top: None,
+            bottom: Some(border_item.clone()),
+            diagonal: None,
+        };
+        assert_eq!(style.border, expected_border);
+    }
+}
+
+#[test]
+fn borders_top() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    // We set an outer border in cells F5:H9
+    let range = &Area {
+        sheet: 0,
+        row: 5,
+        column: 6,
+        width: 3,
+        height: 4,
+    };
+    assert_eq!(number_to_column(6).unwrap(), "F");
+    assert_eq!(number_to_column(8).unwrap(), "H");
+    // ATM we don't have a way to create the object from Rust, that's ok.
+    let border_area: BorderArea = serde_json::from_str(
+        r##"{
+      "item": {
+        "style": "thin",
+        "color": "#FF5566"
+      },
+      "type": "Top"
+    }"##,
+    )
+    .unwrap();
+    model.set_area_with_border(range, &border_area).unwrap();
+    for row in 5..9 {
+        for column in 6..9 {
+            let style = model.get_cell_style(0, row, column).unwrap();
+            let border_item = BorderItem {
+                style: BorderStyle::Thin,
+                color: Some("#FF5566".to_string()),
+            };
+            let expected_border = Border {
+                diagonal_up: false,
+                diagonal_down: false,
+                left: None,
+                right: None,
+                top: Some(border_item.clone()),
+                bottom: None,
+                diagonal: None,
+            };
+            assert_eq!(style.border, expected_border);
+        }
+    }
+}
+
+#[test]
+fn borders_right() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    // We set an outer border in cells F5:H9
+    let range = &Area {
+        sheet: 0,
+        row: 5,
+        column: 6,
+        width: 3,
+        height: 4,
+    };
+    assert_eq!(number_to_column(6).unwrap(), "F");
+    assert_eq!(number_to_column(8).unwrap(), "H");
+    // ATM we don't have a way to create the object from Rust, that's ok.
+    let border_area: BorderArea = serde_json::from_str(
+        r##"{
+      "item": {
+        "style": "thin",
+        "color": "#FF5566"
+      },
+      "type": "Right"
+    }"##,
+    )
+    .unwrap();
+    model.set_area_with_border(range, &border_area).unwrap();
+    for row in 5..9 {
+        for column in 6..9 {
+            let style = model.get_cell_style(0, row, column).unwrap();
+            let border_item = BorderItem {
+                style: BorderStyle::Thin,
+                color: Some("#FF5566".to_string()),
+            };
+            let expected_border = Border {
+                diagonal_up: false,
+                diagonal_down: false,
+                left: None,
+                right: Some(border_item.clone()),
+                top: None,
+                bottom: None,
+                diagonal: None,
+            };
+            assert_eq!(style.border, expected_border);
+        }
+    }
+}
+
+#[test]
+fn borders_bottom() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    // We set an outer border in cells F5:H9
+    let range = &Area {
+        sheet: 0,
+        row: 5,
+        column: 6,
+        width: 3,
+        height: 4,
+    };
+    assert_eq!(number_to_column(6).unwrap(), "F");
+    assert_eq!(number_to_column(8).unwrap(), "H");
+    // ATM we don't have a way to create the object from Rust, that's ok.
+    let border_area: BorderArea = serde_json::from_str(
+        r##"{
+      "item": {
+        "style": "thin",
+        "color": "#FF5566"
+      },
+      "type": "Bottom"
+    }"##,
+    )
+    .unwrap();
+    model.set_area_with_border(range, &border_area).unwrap();
+    for row in 5..9 {
+        for column in 6..9 {
+            let style = model.get_cell_style(0, row, column).unwrap();
+            let border_item = BorderItem {
+                style: BorderStyle::Thin,
+                color: Some("#FF5566".to_string()),
+            };
+            let expected_border = Border {
+                diagonal_up: false,
+                diagonal_down: false,
+                left: None,
+                right: None,
+                top: None,
+                bottom: Some(border_item.clone()),
+                diagonal: None,
+            };
+            assert_eq!(style.border, expected_border);
+        }
+    }
+}
+
+#[test]
+fn borders_left() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    // We set an outer border in cells F5:H9
+    let range = &Area {
+        sheet: 0,
+        row: 5,
+        column: 6,
+        width: 3,
+        height: 4,
+    };
+    assert_eq!(number_to_column(6).unwrap(), "F");
+    assert_eq!(number_to_column(8).unwrap(), "H");
+    // ATM we don't have a way to create the object from Rust, that's ok.
+    let border_area: BorderArea = serde_json::from_str(
+        r##"{
+      "item": {
+        "style": "thin",
+        "color": "#FF5566"
+      },
+      "type": "Left"
+    }"##,
+    )
+    .unwrap();
+    model.set_area_with_border(range, &border_area).unwrap();
+    for row in 5..9 {
+        for column in 6..9 {
+            let style = model.get_cell_style(0, row, column).unwrap();
+            let border_item = BorderItem {
+                style: BorderStyle::Thin,
+                color: Some("#FF5566".to_string()),
+            };
+            let expected_border = Border {
+                diagonal_up: false,
+                diagonal_down: false,
+                left: Some(border_item.clone()),
+                right: None,
+                top: None,
+                bottom: None,
+                diagonal: None,
+            };
+            assert_eq!(style.border, expected_border);
+        }
+    }
+}

base/src/test/user_model/test_clear_cells.rs

@@ -0,0 +1,91 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::{expressions::types::Area, UserModel};
+
+#[test]
+fn basic() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model.set_user_input(0, 1, 1, "100$").unwrap();
+    model
+        .range_clear_contents(&Area {
+            sheet: 0,
+            row: 1,
+            column: 1,
+            width: 1,
+            height: 1,
+        })
+        .unwrap();
+    assert_eq!(model.get_formatted_cell_value(0, 1, 1), Ok("".to_string()));
+    model.undo().unwrap();
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 1),
+        Ok("100$".to_string())
+    );
+    model.redo().unwrap();
+    assert_eq!(model.get_formatted_cell_value(0, 1, 1), Ok("".to_string()));
+
+    model.set_user_input(0, 1, 1, "300").unwrap();
+    // clear contents keeps the formatting
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 1),
+        Ok("300$".to_string())
+    );
+
+    model
+        .range_clear_all(&Area {
+            sheet: 0,
+            row: 1,
+            column: 1,
+            width: 1,
+            height: 1,
+        })
+        .unwrap();
+    assert_eq!(model.get_formatted_cell_value(0, 1, 1), Ok("".to_string()));
+    model.undo().unwrap();
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 1),
+        Ok("300$".to_string())
+    );
+    model.redo().unwrap();
+    assert_eq!(model.get_formatted_cell_value(0, 1, 1), Ok("".to_string()));
+    model.set_user_input(0, 1, 1, "400").unwrap();
+    // clear contents keeps the formatting
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 1),
+        Ok("400".to_string())
+    );
+}
+
+#[test]
+fn clear_empty_cell() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model
+        .range_clear_contents(&Area {
+            sheet: 0,
+            row: 1,
+            column: 1,
+            width: 1,
+            height: 1,
+        })
+        .unwrap();
+    assert_eq!(model.get_formatted_cell_value(0, 1, 1), Ok("".to_string()));
+    model.undo().unwrap();
+    assert_eq!(model.get_formatted_cell_value(0, 1, 1), Ok("".to_string()));
+}
+
+#[test]
+fn clear_all_empty_cell() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model
+        .range_clear_all(&Area {
+            sheet: 0,
+            row: 1,
+            column: 1,
+            width: 1,
+            height: 1,
+        })
+        .unwrap();
+    assert_eq!(model.get_formatted_cell_value(0, 1, 1), Ok("".to_string()));
+    model.undo().unwrap();
+    assert_eq!(model.get_formatted_cell_value(0, 1, 1), Ok("".to_string()));
+}

base/src/test/user_model/test_diff_queue.rs

@@ -0,0 +1,161 @@
+use crate::{
+    constants::{DEFAULT_COLUMN_WIDTH, DEFAULT_ROW_HEIGHT},
+    test::util::new_empty_model,
+    UserModel,
+};
+
+#[test]
+fn send_queue() {
+    let mut model1 = UserModel::from_model(new_empty_model());
+    let width = model1.get_column_width(0, 3).unwrap() * 3.0;
+    model1.set_column_width(0, 3, width).unwrap();
+    model1.set_user_input(0, 1, 2, "Hello IronCalc!").unwrap();
+    let send_queue = model1.flush_send_queue();
+
+    let mut model2 = UserModel::from_model(new_empty_model());
+    model2.apply_external_diffs(&send_queue).unwrap();
+
+    assert_eq!(model2.get_column_width(0, 3), Ok(width));
+    assert_eq!(
+        model2.get_formatted_cell_value(0, 1, 2),
+        Ok("Hello IronCalc!".to_string())
+    );
+}
+
+#[test]
+fn apply_external_diffs_wrong_str() {
+    let mut model1 = UserModel::from_model(new_empty_model());
+    assert!(model1.apply_external_diffs("invalid".as_bytes()).is_err());
+}
+
+#[test]
+fn queue_undo_redo() {
+    let mut model1 = UserModel::from_model(new_empty_model());
+    let width = model1.get_column_width(0, 3).unwrap() * 3.0;
+    model1.set_column_width(0, 3, width).unwrap();
+    model1.set_user_input(0, 1, 2, "Hello IronCalc!").unwrap();
+    assert!(model1.undo().is_ok());
+    assert!(model1.redo().is_ok());
+    let send_queue = model1.flush_send_queue();
+
+    let mut model2 = UserModel::from_model(new_empty_model());
+    model2.apply_external_diffs(&send_queue).unwrap();
+
+    assert_eq!(model2.get_column_width(0, 3), Ok(width));
+    assert_eq!(
+        model2.get_formatted_cell_value(0, 1, 2),
+        Ok("Hello IronCalc!".to_string())
+    );
+}
+
+#[test]
+fn queue_undo_redo_multiple() {
+    let mut model1 = UserModel::from_model(new_empty_model());
+
+    // do a bunch of things
+    model1.set_frozen_columns_count(0, 5).unwrap();
+    model1.set_frozen_rows_count(0, 6).unwrap();
+    model1.set_column_width(0, 7, 300.0).unwrap();
+    model1.set_row_height(0, 23, 123.0).unwrap();
+    model1.set_user_input(0, 55, 55, "=42+8").unwrap();
+
+    for row in 1..5 {
+        model1.set_user_input(0, row, 17, "=ROW()").unwrap();
+    }
+
+    model1.insert_row(0, 3).unwrap();
+    model1.insert_row(0, 3).unwrap();
+
+    // undo al of them
+    while model1.can_undo() {
+        model1.undo().unwrap();
+    }
+
+    // check it is an empty model
+    assert_eq!(model1.get_frozen_columns_count(0), Ok(0));
+    assert_eq!(model1.get_frozen_rows_count(0), Ok(0));
+    assert_eq!(model1.get_column_width(0, 7), Ok(DEFAULT_COLUMN_WIDTH));
+    assert_eq!(
+        model1.get_formatted_cell_value(0, 55, 55),
+        Ok("".to_string())
+    );
+    assert_eq!(model1.get_row_height(0, 23), Ok(DEFAULT_ROW_HEIGHT));
+    assert_eq!(
+        model1.get_formatted_cell_value(0, 57, 55),
+        Ok("".to_string())
+    );
+    assert_eq!(model1.get_row_height(0, 25), Ok(DEFAULT_ROW_HEIGHT));
+
+    // redo all of them
+    while model1.can_redo() {
+        model1.redo().unwrap();
+    }
+
+    // now send all this to a new model
+    let send_queue = model1.flush_send_queue();
+    let mut model2 = UserModel::from_model(new_empty_model());
+    model2.apply_external_diffs(&send_queue).unwrap();
+
+    // Check everything is as expected
+    assert_eq!(model2.get_frozen_columns_count(0), Ok(5));
+    assert_eq!(model2.get_frozen_rows_count(0), Ok(6));
+    assert_eq!(model2.get_column_width(0, 7), Ok(300.0));
+    // I inserted two rows
+    assert_eq!(
+        model2.get_formatted_cell_value(0, 57, 55),
+        Ok("50".to_string())
+    );
+    assert_eq!(model2.get_row_height(0, 25), Ok(123.0));
+
+    assert_eq!(
+        model2.get_formatted_cell_value(0, 1, 17),
+        Ok("1".to_string())
+    );
+    assert_eq!(
+        model2.get_formatted_cell_value(0, 2, 17),
+        Ok("2".to_string())
+    );
+
+    assert_eq!(
+        model2.get_formatted_cell_value(0, 3, 17),
+        Ok("".to_string())
+    );
+    assert_eq!(
+        model2.get_formatted_cell_value(0, 4, 17),
+        Ok("".to_string())
+    );
+
+    assert_eq!(
+        model2.get_formatted_cell_value(0, 5, 17),
+        Ok("5".to_string())
+    );
+    assert_eq!(
+        model2.get_formatted_cell_value(0, 6, 17),
+        Ok("6".to_string())
+    );
+}
+
+#[test]
+fn new_sheet() {
+    let mut model1 = UserModel::from_model(new_empty_model());
+    model1.new_sheet();
+    model1.set_user_input(0, 1, 1, "42").unwrap();
+    model1.set_user_input(1, 1, 1, "=Sheet1!A1*2").unwrap();
+
+    let send_queue = model1.flush_send_queue();
+    let mut model2 = UserModel::from_model(new_empty_model());
+    model2.apply_external_diffs(&send_queue).unwrap();
+
+    assert_eq!(
+        model2.get_formatted_cell_value(1, 1, 1),
+        Ok("84".to_string())
+    );
+}
+
+#[test]
+fn wrong_diffs_handled() {
+    let mut model = UserModel::from_model(new_empty_model());
+    assert!(model
+        .apply_external_diffs("Hello world".as_bytes())
+        .is_err());
+}

base/src/test/user_model/test_evaluation.rs

@@ -0,0 +1,31 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::UserModel;
+
+#[test]
+fn model_evaluates_automatically() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model.set_user_input(0, 1, 1, "=1 + 1").unwrap();
+
+    assert_eq!(model.get_formatted_cell_value(0, 1, 1), Ok("2".to_string()));
+    assert_eq!(model.get_cell_content(0, 1, 1), Ok("=1+1".to_string()));
+}
+
+#[test]
+fn pause_resume_evaluation() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model.pause_evaluation();
+    model.set_user_input(0, 1, 1, "=1+1").unwrap();
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 1),
+        Ok("#ERROR!".to_string())
+    );
+    model.evaluate();
+
+    assert_eq!(model.get_formatted_cell_value(0, 1, 1), Ok("2".to_string()));
+    assert_eq!(model.get_cell_content(0, 1, 1), Ok("=1+1".to_string()));
+
+    model.resume_evaluation();
+    model.set_user_input(0, 2, 1, "=1+4").unwrap();
+    assert_eq!(model.get_formatted_cell_value(0, 2, 1), Ok("5".to_string()));
+}

base/src/test/user_model/test_general.rs

@@ -0,0 +1,131 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::constants::{LAST_COLUMN, LAST_ROW};
+use crate::test::util::new_empty_model;
+use crate::types::CellType;
+use crate::UserModel;
+
+#[test]
+fn set_user_input_errors() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // Wrong sheet
+    assert!(model.set_user_input(1, 1, 1, "1").is_err());
+    // Wrong row
+    assert!(model.set_user_input(0, 0, 1, "1").is_err());
+    // Wrong column
+    assert!(model.set_user_input(0, 1, 0, "1").is_err());
+    // row too large
+    assert!(model.set_user_input(0, LAST_ROW, 1, "1").is_ok());
+    assert!(model.set_user_input(0, LAST_ROW + 1, 1, "1").is_err());
+    // column too large
+    assert!(model.set_user_input(0, 1, LAST_COLUMN, "1").is_ok());
+    assert!(model.set_user_input(0, 1, LAST_COLUMN + 1, "1").is_err());
+}
+
+#[test]
+fn user_model_debug_message() {
+    let model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    let s = &format!("{:?}", model);
+    assert_eq!(s, "UserModel");
+}
+
+#[test]
+fn cell_type() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model.set_user_input(0, 1, 1, "1").unwrap();
+    model.set_user_input(0, 1, 2, "Wish you were here").unwrap();
+    model.set_user_input(0, 1, 3, "true").unwrap();
+    model.set_user_input(0, 1, 4, "=1/0").unwrap();
+
+    assert_eq!(model.get_cell_type(0, 1, 1).unwrap(), CellType::Number);
+    assert_eq!(model.get_cell_type(0, 1, 2).unwrap(), CellType::Text);
+    assert_eq!(
+        model.get_cell_type(0, 1, 3).unwrap(),
+        CellType::LogicalValue
+    );
+    assert_eq!(model.get_cell_type(0, 1, 4).unwrap(), CellType::ErrorValue);
+
+    // empty cells are number type
+    assert_eq!(model.get_cell_type(0, 40, 40).unwrap(), CellType::Number);
+}
+
+#[test]
+fn insert_remove_rows() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    let height = model.get_row_height(0, 5).unwrap();
+
+    // Insert some data in row 5 (and change the style)
+    assert!(model.set_user_input(0, 5, 1, "100$").is_ok());
+    // Change the height of the column
+    assert!(model.set_row_height(0, 5, 3.0 * height).is_ok());
+
+    // remove the row
+    assert!(model.delete_row(0, 5).is_ok());
+    // Row 5 has now the normal height
+    assert_eq!(model.get_row_height(0, 5), Ok(height));
+    // There is no value in A5
+    assert_eq!(model.get_formatted_cell_value(0, 5, 1), Ok("".to_string()));
+    // Setting a value will not format it
+    assert!(model.set_user_input(0, 5, 1, "125").is_ok());
+    assert_eq!(
+        model.get_formatted_cell_value(0, 5, 1),
+        Ok("125".to_string())
+    );
+
+    // undo twice
+    assert!(model.undo().is_ok());
+    assert!(model.undo().is_ok());
+
+    assert_eq!(model.get_row_height(0, 5), Ok(3.0 * height));
+    assert_eq!(
+        model.get_formatted_cell_value(0, 5, 1),
+        Ok("100$".to_string())
+    );
+}
+
+#[test]
+fn insert_remove_columns() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // column E
+    let column_width = model.get_column_width(0, 5).unwrap();
+    println!("{column_width}");
+
+    // Insert some data in row 5 (and change the style) in E1
+    assert!(model.set_user_input(0, 1, 5, "100$").is_ok());
+    // Change the width of the column
+    assert!(model.set_column_width(0, 5, 3.0 * column_width).is_ok());
+    assert_eq!(model.get_column_width(0, 5).unwrap(), 3.0 * column_width);
+
+    // remove the column
+    assert!(model.delete_column(0, 5).is_ok());
+    // Column 5 has now the normal width
+    assert_eq!(model.get_column_width(0, 5), Ok(column_width));
+    // There is no value in E5
+    assert_eq!(model.get_formatted_cell_value(0, 1, 5), Ok("".to_string()));
+    // Setting a value will not format it
+    assert!(model.set_user_input(0, 1, 5, "125").is_ok());
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 5),
+        Ok("125".to_string())
+    );
+
+    // undo twice (set_user_input and delete_column)
+    assert!(model.undo().is_ok());
+    assert!(model.undo().is_ok());
+
+    assert_eq!(model.get_column_width(0, 5), Ok(3.0 * column_width));
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 5),
+        Ok("100$".to_string())
+    );
+}
+
+#[test]
+fn delete_remove_cell() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    let (sheet, row, column) = (0, 1, 1);
+    model.set_user_input(sheet, row, column, "100$").unwrap();
+}

base/src/test/user_model/test_grid_lines.rs

@@ -0,0 +1,42 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::test::util::new_empty_model;
+use crate::UserModel;
+
+#[test]
+fn basic_tests() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.new_sheet();
+
+    // default sheet has show_grid_lines = true
+    assert_eq!(model.get_show_grid_lines(0), Ok(true));
+
+    // default new sheet has show_grid_lines = true
+    assert_eq!(model.get_show_grid_lines(1), Ok(true));
+
+    // wrong sheet number
+    assert_eq!(
+        model.get_show_grid_lines(2),
+        Err("Invalid sheet index".to_string())
+    );
+
+    // we can set it
+    model.set_show_grid_lines(1, false).unwrap();
+    assert_eq!(model.get_show_grid_lines(1), Ok(false));
+    assert_eq!(model.get_show_grid_lines(0), Ok(true));
+
+    model.undo().unwrap();
+
+    assert_eq!(model.get_show_grid_lines(1), Ok(true));
+    assert_eq!(model.get_show_grid_lines(0), Ok(true));
+
+    model.redo().unwrap();
+
+    let send_queue = model.flush_send_queue();
+    let mut model2 = UserModel::from_model(new_empty_model());
+    model2.apply_external_diffs(&send_queue).unwrap();
+
+    assert_eq!(model2.get_show_grid_lines(1), Ok(false));
+    assert_eq!(model2.get_show_grid_lines(0), Ok(true));
+}

base/src/test/user_model/test_keyboard_navigation.rs

@@ -0,0 +1,136 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::{
+    constants::{
+        DEFAULT_COLUMN_WIDTH, DEFAULT_ROW_HEIGHT, DEFAULT_WINDOW_HEIGH, DEFAULT_WINDOW_WIDTH,
+        LAST_COLUMN,
+    },
+    test::util::new_empty_model,
+    UserModel,
+};
+
+#[test]
+fn basic_navigation() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.on_arrow_right().unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(view.range, [1, 2, 1, 2]);
+    assert_eq!(view.column, 2);
+    assert_eq!(view.row, 1);
+
+    model.on_arrow_left().unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(view.range, [1, 1, 1, 1]);
+    assert_eq!(view.column, 1);
+    assert_eq!(view.row, 1);
+
+    model.on_arrow_left().unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(view.range, [1, 1, 1, 1]);
+    assert_eq!(view.column, 1);
+    assert_eq!(view.row, 1);
+
+    model.on_arrow_down().unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(view.range, [2, 1, 2, 1]);
+    assert_eq!(view.column, 1);
+    assert_eq!(view.row, 2);
+
+    model.on_arrow_up().unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(view.range, [1, 1, 1, 1]);
+    assert_eq!(view.column, 1);
+    assert_eq!(view.row, 1);
+
+    model.on_arrow_up().unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(view.range, [1, 1, 1, 1]);
+    assert_eq!(view.column, 1);
+    assert_eq!(view.row, 1);
+}
+
+#[test]
+fn scroll_right() {
+    let window_width = DEFAULT_WINDOW_WIDTH as f64;
+    let column_width = DEFAULT_COLUMN_WIDTH;
+    let column_count = f64::floor(window_width / column_width) as i32;
+
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.on_arrow_right().unwrap();
+
+    model.set_selected_cell(3, column_count).unwrap();
+    model.on_arrow_right().unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(view.left_column, 2);
+
+    model.on_arrow_right().unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(view.left_column, 3);
+}
+
+#[test]
+fn last_colum() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.set_selected_cell(3, LAST_COLUMN).unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(view.column, LAST_COLUMN);
+
+    model.on_arrow_right().unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(view.column, LAST_COLUMN);
+}
+
+#[test]
+fn page_down() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    let window_height = DEFAULT_WINDOW_HEIGH as f64;
+    let row_height = DEFAULT_ROW_HEIGHT;
+    let row_count = f64::floor(window_height / row_height) as i32;
+    model.on_page_down().unwrap();
+
+    let view = model.get_selected_view();
+    assert_eq!(view.row, 1 + row_count);
+    let scroll_y = model.get_scroll_y().unwrap();
+    assert_eq!(scroll_y, (row_count as f64) * DEFAULT_ROW_HEIGHT);
+}
+
+// we just test that page up and page down are inverse operations
+#[test]
+fn page_up() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.on_page_down().unwrap();
+    let row1 = model.get_selected_view().row;
+
+    model.on_page_down().unwrap();
+    let row2 = model.get_selected_view().row;
+
+    model.on_page_down().unwrap();
+    let row3 = model.get_selected_view().row;
+
+    model.on_page_down().unwrap();
+
+    model.on_page_up().unwrap();
+    assert_eq!(model.get_selected_view().row, row3);
+
+    model.on_page_up().unwrap();
+    assert_eq!(model.get_selected_view().row, row2);
+
+    model.on_page_up().unwrap();
+    assert_eq!(model.get_selected_view().row, row1);
+
+    model.on_page_up().unwrap();
+    assert_eq!(model.get_selected_view().row, 1);
+}
+
+#[test]
+fn page_up_fails_on_row1() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.on_arrow_up().unwrap();
+    assert_eq!(model.get_selected_view().row, 1);
+}

base/src/test/user_model/test_on_area_selection.rs

@@ -0,0 +1,33 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::{
+    constants::{DEFAULT_COLUMN_WIDTH, DEFAULT_WINDOW_WIDTH},
+    test::util::new_empty_model,
+    UserModel,
+};
+
+#[test]
+fn basic_test() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+
+    model.on_area_selecting(2, 4).unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(view.range, [1, 1, 2, 4]);
+}
+
+// this checks that is we select in the boundary we automatically scroll
+#[test]
+fn scroll_right() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    let window_width = DEFAULT_WINDOW_WIDTH as f64;
+    let column_width = DEFAULT_COLUMN_WIDTH;
+    let column_count = f64::floor(window_width / column_width) as i32;
+    model.set_selected_cell(3, column_count).unwrap();
+
+    model.on_area_selecting(3, column_count + 3).unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(view.range, [3, column_count, 3, column_count + 3]);
+    assert_eq!(view.left_column, 4);
+}

base/src/test/user_model/test_on_expand_selected_range.rs

@@ -0,0 +1,151 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::{
+    constants::{DEFAULT_COLUMN_WIDTH, DEFAULT_WINDOW_WIDTH, LAST_COLUMN},
+    test::util::new_empty_model,
+    UserModel,
+};
+
+#[test]
+fn arrow_right() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.on_expand_selected_range("ArrowRight").unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(view.range, [1, 1, 1, 2]);
+}
+
+#[test]
+fn arrow_right_decreases() {
+    // if the selected cell is on the upper right corner, right-arrow will decrease the size of teh area
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    let (start_row, start_column, end_row, end_column) = (5, 3, 10, 8);
+    model.set_selected_cell(start_row, end_column).unwrap();
+    model
+        .set_selected_range(start_row, start_column, end_row, end_column)
+        .unwrap();
+
+    model.on_expand_selected_range("ArrowRight").unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(
+        view.range,
+        [start_row, start_column + 1, end_row, end_column]
+    );
+}
+
+#[test]
+fn arrow_right_last_column() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.set_selected_cell(1, LAST_COLUMN).unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(view.range, [1, LAST_COLUMN, 1, LAST_COLUMN]);
+}
+
+#[test]
+fn arrow_right_scroll_right() {
+    let window_width = DEFAULT_WINDOW_WIDTH as f64;
+    let column_width = DEFAULT_COLUMN_WIDTH;
+    let column_count = f64::floor(window_width / column_width) as i32;
+
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+
+    // initially the column to the left is A
+    let view = model.get_selected_view();
+    assert_eq!(view.left_column, 1);
+
+    // We select all columns from 1 to the last visible
+    let (start_row, start_column, end_row, end_column) = (1, 1, 1, column_count);
+    model.set_selected_cell(start_row, start_column).unwrap();
+    model
+        .set_selected_range(start_row, start_column, end_row, end_column)
+        .unwrap();
+
+    // Now we select one more column
+    model.on_expand_selected_range("ArrowRight").unwrap();
+
+    // The view has updated and the first visible column is B
+    let view = model.get_selected_view();
+    assert_eq!(
+        view.range,
+        [start_row, start_column, end_row, end_column + 1]
+    );
+    assert_eq!(view.left_column, 2);
+
+    // now we click on cell B2 and we
+    model.set_selected_cell(2, 2).unwrap();
+    model.on_expand_selected_range("ArrowLeft").unwrap();
+
+    let view = model.get_selected_view();
+    assert_eq!(view.range, [2, 1, 2, 2]);
+    assert_eq!(view.left_column, 1);
+
+    // a second arrow left won't do anything
+    model.on_expand_selected_range("ArrowLeft").unwrap();
+
+    let view = model.get_selected_view();
+    assert_eq!(view.range, [2, 1, 2, 2]);
+    assert_eq!(view.left_column, 1);
+}
+
+#[test]
+fn arrow_left() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.set_selected_cell(5, 3).unwrap();
+    model.set_selected_range(5, 3, 10, 8).unwrap();
+    model.on_expand_selected_range("ArrowLeft").unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(view.range, [5, 3, 10, 7]);
+}
+
+#[test]
+fn arrow_left_left_border() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.on_expand_selected_range("ArrowLeft").unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(view.range, [1, 1, 1, 1]);
+}
+
+#[test]
+fn arrow_left_increases() {
+    // If the selected cell is on the top right corner
+    // arrow left increases the selected area by
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+
+    let (start_row, start_column, end_row, end_column) = (4, 10, 4, 20);
+    model.set_selected_cell(start_row, end_column).unwrap();
+    model
+        .set_selected_range(start_row, start_column, end_row, end_column)
+        .unwrap();
+    model.on_expand_selected_range("ArrowLeft").unwrap();
+    let view = model.get_selected_view();
+    assert_eq!(
+        view.range,
+        [start_row, start_column - 1, end_row, end_column]
+    );
+}
+
+#[test]
+fn arrow_left_scrolls_left() {
+    // If the selected cell is on the top right corner
+    // arrow left increases the selected area by
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+
+    model.set_top_left_visible_cell(1, 50).unwrap();
+
+    model.set_selected_cell(1, 50).unwrap();
+    // arrow left x 2
+    model.on_expand_selected_range("ArrowLeft").unwrap();
+    model.on_expand_selected_range("ArrowLeft").unwrap();
+
+    let view = model.get_selected_view();
+    assert_eq!(view.range, [1, 48, 1, 50]);
+    assert_eq!(view.left_column, 48);
+    assert_eq!(view.column, 50);
+}

base/src/test/user_model/test_on_paste_styles.rs

@@ -0,0 +1,48 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::test::util::new_empty_model;
+use crate::types::Fill;
+use crate::UserModel;
+
+#[test]
+fn simple_pasting() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    let mut style = model.get_cell_style(0, 1, 1).unwrap();
+    style.fill = Fill {
+        pattern_type: "solid".to_string(),
+        fg_color: Some("#FF5577".to_string()),
+        bg_color: Some("#33FF44".to_string()),
+    };
+    let styles = vec![vec![style.clone()]];
+
+    model.set_selected_cell(5, 4).unwrap();
+    model.set_selected_range(5, 4, 10, 9).unwrap();
+    model.on_paste_styles(&styles).unwrap();
+
+    for row in 5..10 {
+        for column in 4..9 {
+            let cell_style = model.get_cell_style(0, row, column).unwrap();
+            assert_eq!(cell_style, style);
+        }
+    }
+
+    model.undo().unwrap();
+    let base_style = model.get_cell_style(0, 100, 100).unwrap();
+
+    for row in 5..10 {
+        for column in 4..9 {
+            let cell_style = model.get_cell_style(0, row, column).unwrap();
+            assert_eq!(cell_style, base_style);
+        }
+    }
+
+    model.redo().unwrap();
+
+    for row in 5..10 {
+        for column in 4..9 {
+            let cell_style = model.get_cell_style(0, row, column).unwrap();
+            assert_eq!(cell_style, style);
+        }
+    }
+}

base/src/test/user_model/test_rename_sheet.rs

@@ -0,0 +1,39 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::UserModel;
+
+#[test]
+fn basic_rename() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model.rename_sheet(0, "NewSheet").unwrap();
+    assert_eq!(model.get_worksheets_properties()[0].name, "NewSheet");
+}
+
+#[test]
+fn undo_redo() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model.rename_sheet(0, "NewSheet").unwrap();
+    model.undo().unwrap();
+    assert_eq!(model.get_worksheets_properties()[0].name, "Sheet1");
+    model.redo().unwrap();
+    assert_eq!(model.get_worksheets_properties()[0].name, "NewSheet");
+
+    let send_queue = model.flush_send_queue();
+
+    let mut model2 = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model2.apply_external_diffs(&send_queue).unwrap();
+    assert_eq!(model.get_worksheets_properties()[0].name, "NewSheet");
+}
+
+#[test]
+fn errors() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    assert_eq!(
+        model.rename_sheet(0, ""),
+        Err("Invalid name for a sheet: ''.".to_string())
+    );
+    assert_eq!(
+        model.rename_sheet(1, "Hello"),
+        Err("Invalid sheet index".to_string())
+    );
+}

base/src/test/user_model/test_row_column.rs

@@ -0,0 +1,156 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::{
+    constants::{DEFAULT_COLUMN_WIDTH, DEFAULT_ROW_HEIGHT, LAST_COLUMN},
+    test::util::new_empty_model,
+    UserModel,
+};
+
+#[test]
+fn simple_insert_row() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    let (sheet, column) = (0, 5);
+    for row in 1..5 {
+        assert!(model.set_user_input(sheet, row, column, "123").is_ok());
+    }
+    assert!(model.insert_row(sheet, 3).is_ok());
+    assert_eq!(
+        model.get_formatted_cell_value(sheet, 3, column).unwrap(),
+        ""
+    );
+
+    assert!(model.undo().is_ok());
+    assert_eq!(
+        model.get_formatted_cell_value(sheet, 3, column).unwrap(),
+        "123"
+    );
+    assert!(model.redo().is_ok());
+    assert_eq!(
+        model.get_formatted_cell_value(sheet, 3, column).unwrap(),
+        ""
+    );
+}
+
+#[test]
+fn simple_insert_column() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    let (sheet, row) = (0, 5);
+    for column in 1..5 {
+        assert!(model.set_user_input(sheet, row, column, "123").is_ok());
+    }
+    assert!(model.insert_column(sheet, 3).is_ok());
+    assert_eq!(model.get_formatted_cell_value(sheet, row, 3).unwrap(), "");
+
+    assert!(model.undo().is_ok());
+    assert_eq!(
+        model.get_formatted_cell_value(sheet, row, 3).unwrap(),
+        "123"
+    );
+    assert!(model.redo().is_ok());
+    assert_eq!(model.get_formatted_cell_value(sheet, row, 3).unwrap(), "");
+}
+
+#[test]
+fn simple_delete_column() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.set_user_input(0, 1, 5, "3").unwrap();
+    model.set_user_input(0, 2, 5, "=E1*2").unwrap();
+    model
+        .set_column_width(0, 5, DEFAULT_COLUMN_WIDTH * 3.0)
+        .unwrap();
+
+    model.delete_column(0, 5).unwrap();
+
+    assert_eq!(model.get_formatted_cell_value(0, 2, 5), Ok("".to_string()));
+    assert_eq!(model.get_column_width(0, 5), Ok(DEFAULT_COLUMN_WIDTH));
+
+    model.undo().unwrap();
+
+    assert_eq!(model.get_formatted_cell_value(0, 2, 5), Ok("6".to_string()));
+    assert_eq!(model.get_column_width(0, 5), Ok(DEFAULT_COLUMN_WIDTH * 3.0));
+
+    let send_queue = model.flush_send_queue();
+
+    let mut model2 = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model2.apply_external_diffs(&send_queue).unwrap();
+
+    assert_eq!(
+        model2.get_formatted_cell_value(0, 2, 5),
+        Ok("6".to_string())
+    );
+    assert_eq!(
+        model2.get_column_width(0, 5),
+        Ok(DEFAULT_COLUMN_WIDTH * 3.0)
+    );
+}
+
+#[test]
+fn delete_column_errors() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    assert_eq!(
+        model.delete_column(1, 1),
+        Err("Invalid sheet index".to_string())
+    );
+
+    assert_eq!(
+        model.delete_column(0, 0),
+        Err("Column number '0' is not valid.".to_string())
+    );
+    assert_eq!(
+        model.delete_column(0, LAST_COLUMN + 1),
+        Err("Column number '16385' is not valid.".to_string())
+    );
+
+    assert_eq!(model.delete_column(0, LAST_COLUMN), Ok(()));
+}
+
+#[test]
+fn simple_delete_row() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.set_user_input(0, 15, 4, "3").unwrap();
+    model.set_user_input(0, 15, 6, "=D15*2").unwrap();
+
+    model
+        .set_row_height(0, 15, DEFAULT_ROW_HEIGHT * 3.0)
+        .unwrap();
+
+    model.delete_row(0, 15).unwrap();
+
+    assert_eq!(model.get_formatted_cell_value(0, 15, 6), Ok("".to_string()));
+    assert_eq!(model.get_row_height(0, 15), Ok(DEFAULT_ROW_HEIGHT));
+
+    model.undo().unwrap();
+
+    assert_eq!(
+        model.get_formatted_cell_value(0, 15, 6),
+        Ok("6".to_string())
+    );
+    assert_eq!(model.get_row_height(0, 15), Ok(DEFAULT_ROW_HEIGHT * 3.0));
+
+    let send_queue = model.flush_send_queue();
+
+    let mut model2 = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model2.apply_external_diffs(&send_queue).unwrap();
+
+    assert_eq!(
+        model2.get_formatted_cell_value(0, 15, 6),
+        Ok("6".to_string())
+    );
+    assert_eq!(model2.get_row_height(0, 15), Ok(DEFAULT_ROW_HEIGHT * 3.0));
+}
+
+#[test]
+fn simple_delete_row_no_style() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.set_user_input(0, 15, 4, "3").unwrap();
+    model.set_user_input(0, 15, 6, "=D15*2").unwrap();
+    model.delete_row(0, 15).unwrap();
+
+    assert_eq!(model.get_formatted_cell_value(0, 15, 6), Ok("".to_string()));
+}

base/src/test/user_model/test_styles.rs

@@ -0,0 +1,723 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::{
+    expressions::types::Area,
+    types::{Alignment, BorderItem, BorderStyle, HorizontalAlignment, VerticalAlignment},
+    UserModel,
+};
+
+#[test]
+fn basic_fonts() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    let range = Area {
+        sheet: 0,
+        row: 1,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert!(!style.font.i);
+    assert!(!style.font.b);
+    assert!(!style.font.u);
+    assert!(!style.font.strike);
+    assert_eq!(style.font.color, Some("#000000".to_owned()));
+
+    // bold
+    model.update_range_style(&range, "font.b", "true").unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert!(style.font.b);
+
+    // italics
+    model.update_range_style(&range, "font.i", "true").unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert!(style.font.i);
+
+    // underline
+    model.update_range_style(&range, "font.u", "true").unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert!(style.font.u);
+
+    // strike
+    model
+        .update_range_style(&range, "font.strike", "true")
+        .unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert!(style.font.strike);
+
+    // color
+    model
+        .update_range_style(&range, "font.color", "#F1F1F1")
+        .unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(style.font.color, Some("#F1F1F1".to_owned()));
+
+    while model.can_undo() {
+        model.undo().unwrap();
+    }
+
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert!(!style.font.i);
+    assert!(!style.font.b);
+    assert!(!style.font.u);
+    assert!(!style.font.strike);
+    assert_eq!(style.font.color, Some("#000000".to_owned()));
+
+    while model.can_redo() {
+        model.redo().unwrap();
+    }
+
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert!(style.font.i);
+    assert!(style.font.b);
+    assert!(style.font.u);
+    assert!(style.font.strike);
+    assert_eq!(style.font.color, Some("#F1F1F1".to_owned()));
+
+    let send_queue = model.flush_send_queue();
+
+    let mut model2 = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model2.apply_external_diffs(&send_queue).unwrap();
+
+    let style = model2.get_cell_style(0, 1, 1).unwrap();
+    assert!(style.font.i);
+    assert!(style.font.b);
+    assert!(style.font.u);
+    assert!(style.font.strike);
+    assert_eq!(style.font.color, Some("#F1F1F1".to_owned()));
+}
+
+#[test]
+fn font_errors() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    let range = Area {
+        sheet: 0,
+        row: 1,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+    assert_eq!(
+        model.update_range_style(&range, "font.b", "True"),
+        Err("Invalid value for boolean: 'True'.".to_string())
+    );
+    assert_eq!(
+        model.update_range_style(&range, "font.i", "FALSE"),
+        Err("Invalid value for boolean: 'FALSE'.".to_string())
+    );
+    assert_eq!(
+        model.update_range_style(&range, "font.bold", "true"),
+        Err("Invalid style path: 'font.bold'.".to_string())
+    );
+    assert_eq!(
+        model.update_range_style(&range, "font.strike", ""),
+        Err("Invalid value for boolean: ''.".to_string())
+    );
+    // There is no cast for booleans
+    assert_eq!(
+        model.update_range_style(&range, "font.b", "1"),
+        Err("Invalid value for boolean: '1'.".to_string())
+    );
+    // colors don't work by name
+    assert_eq!(
+        model.update_range_style(&range, "font.color", "blue"),
+        Err("Invalid color: 'blue'.".to_string())
+    );
+    // No short form
+    assert_eq!(
+        model.update_range_style(&range, "font.color", "#FFF"),
+        Err("Invalid color: '#FFF'.".to_string())
+    );
+}
+
+#[test]
+fn basic_fill() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    let range = Area {
+        sheet: 0,
+        row: 1,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(style.fill.bg_color, None);
+    assert_eq!(style.fill.fg_color, None);
+
+    // bg_color
+    model
+        .update_range_style(&range, "fill.bg_color", "#F2F2F2")
+        .unwrap();
+    model
+        .update_range_style(&range, "fill.fg_color", "#F3F4F5")
+        .unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(style.fill.bg_color, Some("#F2F2F2".to_owned()));
+    assert_eq!(style.fill.fg_color, Some("#F3F4F5".to_owned()));
+
+    let send_queue = model.flush_send_queue();
+
+    let mut model2 = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model2.apply_external_diffs(&send_queue).unwrap();
+
+    let style = model2.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(style.fill.bg_color, Some("#F2F2F2".to_owned()));
+    assert_eq!(style.fill.fg_color, Some("#F3F4F5".to_owned()));
+}
+
+#[test]
+fn fill_errors() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    let range = Area {
+        sheet: 0,
+        row: 1,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+    assert_eq!(
+        model.update_range_style(&range, "fill.bg_color", "#FFF"),
+        Err("Invalid color: '#FFF'.".to_string())
+    );
+
+    assert_eq!(
+        model.update_range_style(&range, "fill.fg_color", "#FFF"),
+        Err("Invalid color: '#FFF'.".to_string())
+    );
+}
+
+#[test]
+fn basic_format() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    let range = Area {
+        sheet: 0,
+        row: 1,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(style.num_fmt, "general");
+
+    model
+        .update_range_style(&range, "num_fmt", "$#,##0.0000")
+        .unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(style.num_fmt, "$#,##0.0000");
+
+    model.undo().unwrap();
+
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(style.num_fmt, "general");
+
+    model.redo().unwrap();
+
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(style.num_fmt, "$#,##0.0000");
+
+    let send_queue = model.flush_send_queue();
+
+    let mut model2 = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model2.apply_external_diffs(&send_queue).unwrap();
+
+    let style = model2.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(style.num_fmt, "$#,##0.0000");
+}
+
+#[test]
+fn basic_borders() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    let range = Area {
+        sheet: 0,
+        row: 1,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+
+    model
+        .update_range_style(&range, "border.left", "thin,#F1F1F1")
+        .unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(
+        style.border.left,
+        Some(BorderItem {
+            style: BorderStyle::Thin,
+            color: Some("#F1F1F1".to_owned()),
+        })
+    );
+
+    model
+        .update_range_style(&range, "border.left", "thin,")
+        .unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(
+        style.border.left,
+        Some(BorderItem {
+            style: BorderStyle::Thin,
+            color: None,
+        })
+    );
+
+    model
+        .update_range_style(&range, "border.right", "dotted,#F1F1F2")
+        .unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(
+        style.border.right,
+        Some(BorderItem {
+            style: BorderStyle::Dotted,
+            color: Some("#F1F1F2".to_owned()),
+        })
+    );
+
+    model
+        .update_range_style(&range, "border.top", "double,#F1F1F3")
+        .unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(
+        style.border.top,
+        Some(BorderItem {
+            style: BorderStyle::Double,
+            color: Some("#F1F1F3".to_owned()),
+        })
+    );
+
+    model
+        .update_range_style(&range, "border.bottom", "medium,#F1F1F4")
+        .unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(
+        style.border.bottom,
+        Some(BorderItem {
+            style: BorderStyle::Medium,
+            color: Some("#F1F1F4".to_owned()),
+        })
+    );
+
+    while model.can_undo() {
+        model.undo().unwrap();
+    }
+
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(style.border.left, None);
+    assert_eq!(style.border.top, None);
+    assert_eq!(style.border.right, None);
+    assert_eq!(style.border.bottom, None);
+
+    while model.can_redo() {
+        model.redo().unwrap();
+    }
+
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(
+        style.border.left,
+        Some(BorderItem {
+            style: BorderStyle::Thin,
+            color: None,
+        })
+    );
+    assert_eq!(
+        style.border.right,
+        Some(BorderItem {
+            style: BorderStyle::Dotted,
+            color: Some("#F1F1F2".to_owned()),
+        })
+    );
+    assert_eq!(
+        style.border.top,
+        Some(BorderItem {
+            style: BorderStyle::Double,
+            color: Some("#F1F1F3".to_owned()),
+        })
+    );
+    assert_eq!(
+        style.border.bottom,
+        Some(BorderItem {
+            style: BorderStyle::Medium,
+            color: Some("#F1F1F4".to_owned()),
+        })
+    );
+
+    let send_queue = model.flush_send_queue();
+
+    let mut model2 = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model2.apply_external_diffs(&send_queue).unwrap();
+
+    let style = model2.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(
+        style.border.left,
+        Some(BorderItem {
+            style: BorderStyle::Thin,
+            color: None,
+        })
+    );
+    assert_eq!(
+        style.border.right,
+        Some(BorderItem {
+            style: BorderStyle::Dotted,
+            color: Some("#F1F1F2".to_owned()),
+        })
+    );
+    assert_eq!(
+        style.border.top,
+        Some(BorderItem {
+            style: BorderStyle::Double,
+            color: Some("#F1F1F3".to_owned()),
+        })
+    );
+    assert_eq!(
+        style.border.bottom,
+        Some(BorderItem {
+            style: BorderStyle::Medium,
+            color: Some("#F1F1F4".to_owned()),
+        })
+    );
+}
+
+#[test]
+fn basic_alignment() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    let range = Area {
+        sheet: 0,
+        row: 1,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+
+    let alignment = model.get_cell_style(0, 1, 1).unwrap().alignment;
+    assert_eq!(alignment, None);
+
+    model
+        .update_range_style(&range, "alignment.horizontal", "center")
+        .unwrap();
+    let alignment = model.get_cell_style(0, 1, 1).unwrap().alignment;
+    assert_eq!(
+        alignment,
+        Some(Alignment {
+            horizontal: HorizontalAlignment::Center,
+            vertical: VerticalAlignment::Bottom,
+            wrap_text: false
+        })
+    );
+
+    model
+        .update_range_style(&range, "alignment.horizontal", "centerContinuous")
+        .unwrap();
+    let alignment = model.get_cell_style(0, 1, 1).unwrap().alignment;
+    assert_eq!(
+        alignment,
+        Some(Alignment {
+            horizontal: HorizontalAlignment::CenterContinuous,
+            vertical: VerticalAlignment::Bottom,
+            wrap_text: false
+        })
+    );
+
+    let range = Area {
+        sheet: 0,
+        row: 2,
+        column: 2,
+        width: 1,
+        height: 1,
+    };
+
+    model
+        .update_range_style(&range, "alignment.vertical", "distributed")
+        .unwrap();
+    let alignment = model.get_cell_style(0, 2, 2).unwrap().alignment;
+    assert_eq!(
+        alignment,
+        Some(Alignment {
+            horizontal: HorizontalAlignment::General,
+            vertical: VerticalAlignment::Distributed,
+            wrap_text: false
+        })
+    );
+
+    model
+        .update_range_style(&range, "alignment.vertical", "justify")
+        .unwrap();
+    let alignment = model.get_cell_style(0, 2, 2).unwrap().alignment;
+    assert_eq!(
+        alignment,
+        Some(Alignment {
+            horizontal: HorizontalAlignment::General,
+            vertical: VerticalAlignment::Justify,
+            wrap_text: false
+        })
+    );
+
+    model.update_range_style(&range, "alignment", "").unwrap();
+    let alignment = model.get_cell_style(0, 2, 2).unwrap().alignment;
+    assert_eq!(alignment, None);
+
+    model.undo().unwrap();
+
+    let alignment = model.get_cell_style(0, 2, 2).unwrap().alignment;
+    assert_eq!(
+        alignment,
+        Some(Alignment {
+            horizontal: HorizontalAlignment::General,
+            vertical: VerticalAlignment::Justify,
+            wrap_text: false
+        })
+    );
+}
+
+#[test]
+fn alignment_errors() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    let range = Area {
+        sheet: 0,
+        row: 1,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+
+    assert_eq!(
+        model.update_range_style(&range, "alignment", "some"),
+        Err("Alignment must be empty, but found: 'some'.".to_string())
+    );
+
+    assert_eq!(
+        model.update_range_style(&range, "alignment.vertical", "justified"),
+        Err("Invalid value for vertical alignment: 'justified'.".to_string())
+    );
+
+    assert_eq!(
+        model.update_range_style(&range, "alignment.horizontal", "unjustified"),
+        Err("Invalid value for horizontal alignment: 'unjustified'.".to_string())
+    );
+
+    model
+        .update_range_style(&range, "alignment.vertical", "justify")
+        .unwrap();
+
+    // Also fail if there is an alignment
+
+    assert_eq!(
+        model.update_range_style(&range, "alignment", "some"),
+        Err("Alignment must be empty, but found: 'some'.".to_string())
+    );
+
+    assert_eq!(
+        model.update_range_style(&range, "alignment.vertical", "justified"),
+        Err("Invalid value for vertical alignment: 'justified'.".to_string())
+    );
+
+    assert_eq!(
+        model.update_range_style(&range, "alignment.horizontal", "unjustified"),
+        Err("Invalid value for horizontal alignment: 'unjustified'.".to_string())
+    );
+}
+
+#[test]
+fn basic_wrap_text() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    let range = Area {
+        sheet: 0,
+        row: 1,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+    assert_eq!(
+        model.update_range_style(&range, "alignment.wrap_text", "T"),
+        Err("Invalid value for boolean: 'T'.".to_string())
+    );
+    model
+        .update_range_style(&range, "alignment.wrap_text", "true")
+        .unwrap();
+    let alignment = model.get_cell_style(0, 1, 1).unwrap().alignment;
+    assert_eq!(
+        alignment,
+        Some(Alignment {
+            horizontal: HorizontalAlignment::General,
+            vertical: VerticalAlignment::Bottom,
+            wrap_text: true
+        })
+    );
+    model.undo().unwrap();
+    let alignment = model.get_cell_style(0, 1, 1).unwrap().alignment;
+    assert_eq!(alignment, None);
+
+    model.redo().unwrap();
+
+    let alignment = model.get_cell_style(0, 1, 1).unwrap().alignment;
+    assert_eq!(
+        alignment,
+        Some(Alignment {
+            horizontal: HorizontalAlignment::General,
+            vertical: VerticalAlignment::Bottom,
+            wrap_text: true
+        })
+    );
+
+    assert_eq!(
+        model.update_range_style(&range, "alignment.wrap_text", "True"),
+        Err("Invalid value for boolean: 'True'.".to_string())
+    );
+}
+
+#[test]
+fn more_basic_borders() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    let range = Area {
+        sheet: 0,
+        row: 1,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+
+    model
+        .update_range_style(&range, "border.left", "thick,#F1F1F1")
+        .unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(
+        style.border.left,
+        Some(BorderItem {
+            style: BorderStyle::Thick,
+            color: Some("#F1F1F1".to_owned()),
+        })
+    );
+
+    model
+        .update_range_style(&range, "border.left", "slantDashDot,#F1F1F1")
+        .unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(
+        style.border.left,
+        Some(BorderItem {
+            style: BorderStyle::SlantDashDot,
+            color: Some("#F1F1F1".to_owned()),
+        })
+    );
+
+    model
+        .update_range_style(&range, "border.left", "mediumDashDot,#F1F1F1")
+        .unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(
+        style.border.left,
+        Some(BorderItem {
+            style: BorderStyle::MediumDashDot,
+            color: Some("#F1F1F1".to_owned()),
+        })
+    );
+
+    model
+        .update_range_style(&range, "border.left", "mediumDashDotDot,#F1F1F1")
+        .unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(
+        style.border.left,
+        Some(BorderItem {
+            style: BorderStyle::MediumDashDotDot,
+            color: Some("#F1F1F1".to_owned()),
+        })
+    );
+
+    model
+        .update_range_style(&range, "border.left", "mediumDashed,#F1F1F1")
+        .unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(
+        style.border.left,
+        Some(BorderItem {
+            style: BorderStyle::MediumDashed,
+            color: Some("#F1F1F1".to_owned()),
+        })
+    );
+}
+
+#[test]
+fn border_errors() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    let range = Area {
+        sheet: 0,
+        row: 1,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+
+    assert_eq!(
+        model.update_range_style(&range, "border.lef", "thick,#F1F1F1"),
+        Err("Invalid style path: 'border.lef'.".to_string())
+    );
+
+    assert_eq!(
+        model.update_range_style(&range, "border.left", "thic,#F1F1F1"),
+        Err("Invalid border style: 'thic'.".to_string())
+    );
+
+    assert_eq!(
+        model.update_range_style(&range, "border.left", "thick,#F1F1F"),
+        Err("Invalid color: '#F1F1F'.".to_string())
+    );
+
+    assert_eq!(
+        model.update_range_style(&range, "border.left", " "),
+        Err("Invalid border value: ' '.".to_string())
+    );
+
+    assert_eq!(
+        model.update_range_style(&range, "border.left", "thick,#F1F1F1,thin"),
+        Err("Invalid border value: 'thick,#F1F1F1,thin'.".to_string())
+    );
+}
+
+#[test]
+fn empty_removes_border() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    let range = Area {
+        sheet: 0,
+        row: 1,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+    model
+        .update_range_style(&range, "border.left", "mediumDashDotDot,#F1F1F1")
+        .unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(
+        style.border.left,
+        Some(BorderItem {
+            style: BorderStyle::MediumDashDotDot,
+            color: Some("#F1F1F1".to_owned()),
+        })
+    );
+
+    model.update_range_style(&range, "border.left", "").unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert_eq!(style.border.left, None);
+}
+
+#[test]
+fn false_removes_value() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    let range = Area {
+        sheet: 0,
+        row: 1,
+        column: 1,
+        width: 1,
+        height: 1,
+    };
+
+    // bold
+    model.update_range_style(&range, "font.b", "true").unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert!(style.font.b);
+
+    model.update_range_style(&range, "font.b", "false").unwrap();
+    let style = model.get_cell_style(0, 1, 1).unwrap();
+    assert!(!style.font.b);
+}

base/src/test/user_model/test_to_from_bytes.rs

@@ -0,0 +1,30 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::{test::util::new_empty_model, UserModel};
+
+#[test]
+fn basic() {
+    let mut model1 = UserModel::from_model(new_empty_model());
+    let width = model1.get_column_width(0, 3).unwrap() * 3.0;
+    model1.set_column_width(0, 3, width).unwrap();
+    model1.set_user_input(0, 1, 2, "Hello IronCalc!").unwrap();
+
+    let model_bytes = model1.to_bytes();
+
+    let model2 = UserModel::from_bytes(&model_bytes).unwrap();
+
+    assert_eq!(model2.get_column_width(0, 3), Ok(width));
+    assert_eq!(
+        model2.get_formatted_cell_value(0, 1, 2),
+        Ok("Hello IronCalc!".to_string())
+    );
+}
+
+#[test]
+fn errors() {
+    let model_bytes = "Early in the morning, late in the century, Cricklewood Broadway.".as_bytes();
+    assert_eq!(
+        &UserModel::from_bytes(model_bytes).unwrap_err(),
+        "Error parsing workbook: invalid packing"
+    );
+}

base/src/test/user_model/test_undo_redo.rs

@@ -0,0 +1,66 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::{test::util::new_empty_model, UserModel};
+
+#[test]
+fn simple_undo_redo() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    // at the beginning I cannot undo or redo
+    assert!(!model.can_undo());
+    assert!(!model.can_redo());
+    assert!(model.set_user_input(0, 1, 1, "=1+2").is_ok());
+
+    // Once I enter a value I can undo but not redo
+    assert!(model.can_undo());
+    assert!(!model.can_redo());
+    assert_eq!(model.get_formatted_cell_value(0, 1, 1), Ok("3".to_string()));
+
+    // If I undo, I can't undo anymore, but I can redo
+    assert!(model.undo().is_ok());
+    assert!(!model.can_undo());
+    assert!(model.can_redo());
+    assert_eq!(model.get_formatted_cell_value(0, 1, 1), Ok("".to_string()));
+
+    // If I redo, I have the old value and formula
+    assert!(model.redo().is_ok());
+    assert_eq!(model.get_formatted_cell_value(0, 1, 1), Ok("3".to_string()));
+    assert_eq!(model.get_cell_content(0, 1, 1), Ok("=1+2".to_string()));
+    assert!(model.can_undo());
+    assert!(!model.can_redo());
+}
+
+#[test]
+fn undo_redo_respect_styles() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    assert!(model.set_user_input(0, 1, 1, "100").is_ok());
+    assert!(model.set_user_input(0, 1, 1, "125$").is_ok());
+    // The content of the cell is just the number 125
+    assert_eq!(model.get_cell_content(0, 1, 1), Ok("125".to_string()));
+    assert!(model.undo().is_ok());
+    // The cell has no currency number formatting
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 1),
+        Ok("100".to_string())
+    );
+    assert_eq!(model.get_cell_content(0, 1, 1), Ok("100".to_string()));
+    assert!(model.redo().is_ok());
+    // The cell has the number 125 formatted as '125$'
+    assert_eq!(
+        model.get_formatted_cell_value(0, 1, 1),
+        Ok("125$".to_string())
+    );
+    assert_eq!(model.get_cell_content(0, 1, 1), Ok("125".to_string()));
+}
+
+#[test]
+fn can_undo_can_redo() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    assert!(!model.can_undo());
+    assert!(!model.can_redo());
+
+    assert!(model.undo().is_ok());
+    assert!(model.redo().is_ok());
+}

base/src/test/user_model/test_view.rs

@@ -0,0 +1,209 @@
+#![allow(clippy::unwrap_used)]
+
+use std::collections::HashMap;
+
+use crate::{
+    constants::{LAST_COLUMN, LAST_ROW},
+    test::util::new_empty_model,
+    user_model::SelectedView,
+    UserModel,
+};
+
+#[test]
+fn initial_view() {
+    let model = new_empty_model();
+    let model = UserModel::from_model(model);
+    assert_eq!(model.get_selected_sheet(), 0);
+    assert_eq!(model.get_selected_cell(), (0, 1, 1));
+    assert_eq!(
+        model.get_selected_view(),
+        SelectedView {
+            sheet: 0,
+            row: 1,
+            column: 1,
+            range: [1, 1, 1, 1],
+            top_row: 1,
+            left_column: 1
+        }
+    );
+}
+
+#[test]
+fn set_the_cell_sets_the_range() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.set_selected_cell(5, 4).unwrap();
+    assert_eq!(model.get_selected_sheet(), 0);
+    assert_eq!(model.get_selected_cell(), (0, 5, 4));
+    assert_eq!(
+        model.get_selected_view(),
+        SelectedView {
+            sheet: 0,
+            row: 5,
+            column: 4,
+            range: [5, 4, 5, 4],
+            top_row: 1,
+            left_column: 1
+        }
+    );
+}
+
+#[test]
+fn set_the_range_does_not_set_the_cell() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    assert_eq!(
+        model.set_selected_range(5, 4, 10, 6),
+        Err(
+            "The selected cells is not in one of the corners. Row: '1' and row range '(5, 10)'"
+                .to_string()
+        )
+    );
+}
+
+#[test]
+fn add_new_sheet_and_back() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.new_sheet();
+    assert_eq!(model.get_selected_sheet(), 0);
+    model.set_selected_cell(5, 4).unwrap();
+    model.set_selected_sheet(1).unwrap();
+    assert_eq!(model.get_selected_cell(), (1, 1, 1));
+    model.set_selected_sheet(0).unwrap();
+    assert_eq!(model.get_selected_cell(), (0, 5, 4));
+}
+
+#[test]
+fn set_selected_cell_errors() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    assert_eq!(
+        model.set_selected_cell(-5, 4),
+        Err("Invalid row: '-5'".to_string())
+    );
+    assert_eq!(
+        model.set_selected_cell(5, -4),
+        Err("Invalid column: '-4'".to_string())
+    );
+    assert_eq!(
+        model.set_selected_range(-1, 1, 1, 1),
+        Err("Invalid row: '-1'".to_string())
+    );
+    assert_eq!(
+        model.set_selected_range(1, 0, 1, 1),
+        Err("Invalid column: '0'".to_string())
+    );
+    assert_eq!(
+        model.set_selected_range(1, 1, LAST_ROW + 1, 1),
+        Err("Invalid row: '1048577'".to_string())
+    );
+    assert_eq!(
+        model.set_selected_range(1, 1, 1, LAST_COLUMN + 1),
+        Err("Invalid column: '16385'".to_string())
+    );
+}
+
+#[test]
+fn set_selected_cell_errors_wrong_sheet() {
+    let mut model = new_empty_model();
+    // forcefully set a wrong index
+    model.workbook.views.get_mut(&0).unwrap().sheet = 2;
+    let mut model = UserModel::from_model(model);
+    // It's returning the wrong number
+    assert_eq!(model.get_selected_sheet(), 2);
+
+    // But we can't set the selected cell anymore
+    assert_eq!(
+        model.set_selected_cell(3, 4),
+        Err("Invalid worksheet index 2".to_string())
+    );
+    assert_eq!(
+        model.set_selected_range(3, 4, 5, 6),
+        Err("Invalid worksheet index 2".to_string())
+    );
+
+    assert_eq!(
+        model.set_top_left_visible_cell(3, 4),
+        Err("Invalid worksheet index 2".to_string())
+    );
+
+    // we can fix it by setting the right cell
+    model.set_selected_sheet(0).unwrap();
+    model.set_selected_cell(3, 4).unwrap();
+}
+
+#[test]
+fn set_visible_cell() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    model.set_top_left_visible_cell(100, 12).unwrap();
+
+    assert_eq!(
+        model.get_selected_view(),
+        SelectedView {
+            sheet: 0,
+            row: 1,
+            column: 1,
+            range: [1, 1, 1, 1],
+            top_row: 100,
+            left_column: 12
+        }
+    );
+
+    let s = serde_json::to_string(&model.get_selected_view()).unwrap();
+    assert_eq!(
+        serde_json::from_str::<SelectedView>(&s).unwrap(),
+        SelectedView {
+            sheet: 0,
+            row: 1,
+            column: 1,
+            range: [1, 1, 1, 1],
+            top_row: 100,
+            left_column: 12
+        }
+    );
+}
+
+#[test]
+fn set_visible_cell_errors() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    assert_eq!(
+        model.set_top_left_visible_cell(-100, 12),
+        Err("Invalid row: '-100'".to_string())
+    );
+    assert_eq!(
+        model.set_top_left_visible_cell(100, -12),
+        Err("Invalid column: '-12'".to_string())
+    );
+}
+
+#[test]
+fn errors_no_views() {
+    let mut model = new_empty_model();
+    // forcefully remove the view
+    model.workbook.views = HashMap::new();
+    // also in the sheet
+    model.workbook.worksheets[0].views = HashMap::new();
+    let mut model = UserModel::from_model(model);
+    // get methods will return defaults
+    assert_eq!(model.get_selected_sheet(), 0);
+    assert_eq!(model.get_selected_cell(), (0, 1, 1));
+    assert_eq!(
+        model.get_selected_view(),
+        SelectedView {
+            sheet: 0,
+            row: 1,
+            column: 1,
+            range: [1, 1, 1, 1],
+            top_row: 1,
+            left_column: 1
+        }
+    );
+
+    // set methods won't complain. but won't work either
+    model.set_selected_sheet(0).unwrap();
+    model.set_selected_cell(5, 6).unwrap();
+    assert_eq!(model.get_selected_cell(), (0, 1, 1));
+}

base/src/test/user_model/test_window_size.rs

@@ -0,0 +1,29 @@
+#![allow(clippy::unwrap_used)]
+
+use crate::{
+    constants::{DEFAULT_ROW_HEIGHT, DEFAULT_WINDOW_HEIGH, DEFAULT_WINDOW_WIDTH},
+    test::util::new_empty_model,
+    UserModel,
+};
+
+#[test]
+fn basic_test() {
+    let model = new_empty_model();
+    let mut model = UserModel::from_model(model);
+    let window_height = model.get_window_height().unwrap();
+    assert_eq!(window_height, DEFAULT_WINDOW_HEIGH);
+
+    let window_width = model.get_window_width().unwrap();
+    assert_eq!(window_width, DEFAULT_WINDOW_WIDTH);
+
+    // Set the window height to double the default and check that page_down behaves as expected
+    model.set_window_height((window_height * 2) as f64);
+    model.on_page_down().unwrap();
+
+    let row_height = DEFAULT_ROW_HEIGHT;
+    let row_count = f64::floor((window_height * 2) as f64 / row_height) as i32;
+    let view = model.get_selected_view();
+    assert_eq!(view.row, 1 + row_count);
+    let scroll_y = model.get_scroll_y().unwrap();
+    assert_eq!(scroll_y, (row_count as f64) * DEFAULT_ROW_HEIGHT);
+}

base/src/test/util.rs

@@ -20,7 +20,8 @@ impl Model {
         let cell_reference = self._parse_reference(cell);
         let column = cell_reference.column;
         let row = cell_reference.row;
-        self.set_user_input(cell_reference.sheet, row, column, value.to_string());
+        self.set_user_input(cell_reference.sheet, row, column, value.to_string())
+            .unwrap();
     }
     pub fn _has_formula(&self, cell: &str) -> bool {
         self._get_formula_opt(cell).is_some()
@@ -32,11 +33,11 @@ impl Model {
         let cell_reference = self._parse_reference(cell);
         let column = cell_reference.column;
         let row = cell_reference.row;
-        self.cell_formula(cell_reference.sheet, row, column)
+        self.get_cell_formula(cell_reference.sheet, row, column)
             .unwrap()
     }
     pub fn _get_text_at(&self, sheet: u32, row: i32, column: i32) -> String {
-        self.formatted_cell_value(sheet, row, column).unwrap()
+        self.get_formatted_cell_value(sheet, row, column).unwrap()
     }
     pub fn _get_text(&self, cell: &str) -> String {
         let CellReferenceIndex { sheet, row, column } = self._parse_reference(cell);

base/src/types.rs

@@ -1,39 +1,18 @@
+use bitcode::{Decode, Encode};
 use serde::{Deserialize, Serialize};
 use std::{collections::HashMap, fmt::Display};
 
 use crate::expressions::token::Error;
 
-// Useful for `#[serde(default = "default_as_true")]`
-fn default_as_true() -> bool {
-    true
-}
-
 fn default_as_false() -> bool {
     false
 }
 
-// Useful for `#[serde(skip_serializing_if = "is_true")]`
-fn is_true(b: &bool) -> bool {
-    *b
-}
-
 fn is_false(b: &bool) -> bool {
     !*b
 }
 
-fn is_zero(num: &i32) -> bool {
-    *num == 0
-}
-
-fn is_default_alignment(o: &Option<Alignment>) -> bool {
-    o.is_none() || *o == Some(Alignment::default())
-}
-
-fn hashmap_is_empty(h: &HashMap<String, Table>) -> bool {
-    h.values().len() == 0
-}
-
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Encode, Decode, Debug, PartialEq, Eq, Clone)]
 pub struct Metadata {
     pub application: String,
     pub app_version: String,
@@ -43,14 +22,25 @@ pub struct Metadata {
     pub last_modified: String, //"2020-11-20T16:24:35"
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Encode, Decode, Debug, PartialEq, Eq, Clone)]
 pub struct WorkbookSettings {
     pub tz: String,
     pub locale: String,
 }
+
+/// A Workbook View tracks of the selected sheet for each view
+#[derive(Encode, Decode, Debug, PartialEq, Clone)]
+pub struct WorkbookView {
+    /// The index of the currently selected sheet.
+    pub sheet: u32,
+    /// The current width of the window
+    pub window_width: i64,
+    /// The current heigh of the window
+    pub window_height: i64,
+}
+
 /// An internal representation of an IronCalc Workbook
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
-#[serde(deny_unknown_fields)]
+#[derive(Encode, Decode, Debug, PartialEq, Clone)]
 pub struct Workbook {
     pub shared_strings: Vec<String>,
     pub defined_names: Vec<DefinedName>,
@@ -59,28 +49,22 @@ pub struct Workbook {
     pub name: String,
     pub settings: WorkbookSettings,
     pub metadata: Metadata,
-    #[serde(default)]
-    #[serde(skip_serializing_if = "hashmap_is_empty")]
     pub tables: HashMap<String, Table>,
+    pub views: HashMap<u32, WorkbookView>,
 }
 
 /// A defined name. The `sheet_id` is the sheet index in case the name is local
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Encode, Decode, Debug, PartialEq, Eq, Clone)]
 pub struct DefinedName {
     pub name: String,
     pub formula: String,
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub sheet_id: Option<u32>,
 }
 
-// TODO: Move to worksheet.rs make frozen_rows/columns private and u32
-/// Internal representation of a worksheet Excel object
-
 /// * state:
 ///    18.18.68 ST_SheetState (Sheet Visibility Types)
 ///    hidden, veryHidden, visible
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
-#[serde(rename_all = "lowercase")]
+#[derive(Encode, Decode, Debug, PartialEq, Eq, Clone)]
 pub enum SheetState {
     Visible,
     Hidden,
@@ -97,8 +81,25 @@ impl Display for SheetState {
     }
 }
 
+/// Represents the state of the worksheet as seen by the user. This includes
+/// details such as the currently selected cell, the visible range, and the
+/// position of the viewport.
+#[derive(Encode, Decode, Debug, PartialEq, Clone)]
+pub struct WorksheetView {
+    /// The row index of the currently selected cell.
+    pub row: i32,
+    /// The column index of the currently selected cell.
+    pub column: i32,
+    /// The selected range in the worksheet, specified as [start_row, start_column, end_row, end_column].
+    pub range: [i32; 4],
+    /// The row index of the topmost visible cell in the worksheet view.
+    pub top_row: i32,
+    /// The column index of the leftmost visible cell in the worksheet view.
+    pub left_column: i32,
+}
+
 /// Internal representation of a worksheet Excel object
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Encode, Decode, Debug, PartialEq, Clone)]
 pub struct Worksheet {
     pub dimension: String,
     pub cols: Vec<Col>,
@@ -108,16 +109,14 @@ pub struct Worksheet {
     pub shared_formulas: Vec<String>,
     pub sheet_id: u32,
     pub state: SheetState,
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub color: Option<String>,
     pub merge_cells: Vec<String>,
     pub comments: Vec<Comment>,
-    #[serde(default)]
-    #[serde(skip_serializing_if = "is_zero")]
     pub frozen_rows: i32,
-    #[serde(default)]
-    #[serde(skip_serializing_if = "is_zero")]
     pub frozen_columns: i32,
+    pub views: HashMap<u32, WorksheetView>,
+    /// Whether or not to show the grid lines in the worksheet
+    pub show_grid_lines: bool,
 }
 
 /// Internal representation of Excel's sheet_data
@@ -125,7 +124,7 @@ pub struct Worksheet {
 pub type SheetData = HashMap<i32, HashMap<i32, Cell>>;
 
 // ECMA-376-1:2016 section 18.3.1.73
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Encode, Decode, Debug, PartialEq, Clone)]
 pub struct Row {
     /// Row index
     pub r: i32,
@@ -133,23 +132,19 @@ pub struct Row {
     pub custom_format: bool,
     pub custom_height: bool,
     pub s: i32,
-    #[serde(default = "default_as_false")]
-    #[serde(skip_serializing_if = "is_false")]
     pub hidden: bool,
 }
 
 // ECMA-376-1:2016 section 18.3.1.13
-#[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
+#[derive(Encode, Decode, Debug, PartialEq, Clone)]
 pub struct Col {
     // Column definitions are defined on ranges, unlike rows which store unique, per-row entries.
     /// First column affected by this record. Settings apply to column in \[min, max\] range.
     pub min: i32,
     /// Last column affected by this record. Settings apply to column in \[min, max\] range.
     pub max: i32,
-
     pub width: f64,
     pub custom_width: bool,
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub style: Option<i32>,
 }
 
@@ -164,32 +159,55 @@ pub enum CellType {
     CompoundData = 128,
 }
 
-#[derive(Serialize, Deserialize, Debug, Clone, PartialEq)]
-#[serde(tag = "t", deny_unknown_fields)]
+#[derive(Encode, Decode, Debug, Clone, PartialEq)]
 pub enum Cell {
-    #[serde(rename = "empty")]
-    EmptyCell { s: i32 },
-    #[serde(rename = "b")]
-    BooleanCell { v: bool, s: i32 },
-    #[serde(rename = "n")]
-    NumberCell { v: f64, s: i32 },
+    EmptyCell {
+        s: i32,
+    },
+
+    BooleanCell {
+        v: bool,
+        s: i32,
+    },
+
+    NumberCell {
+        v: f64,
+        s: i32,
+    },
     // Maybe we should not have this type. In Excel this is just a string
-    #[serde(rename = "e")]
-    ErrorCell { ei: Error, s: i32 },
+    ErrorCell {
+        ei: Error,
+        s: i32,
+    },
     // Always a shared string
-    #[serde(rename = "s")]
-    SharedString { si: i32, s: i32 },
+    SharedString {
+        si: i32,
+        s: i32,
+    },
     // Non evaluated Formula
-    #[serde(rename = "u")]
-    CellFormula { f: i32, s: i32 },
-    #[serde(rename = "fb")]
-    CellFormulaBoolean { f: i32, v: bool, s: i32 },
-    #[serde(rename = "fn")]
-    CellFormulaNumber { f: i32, v: f64, s: i32 },
+    CellFormula {
+        f: i32,
+        s: i32,
+    },
+
+    CellFormulaBoolean {
+        f: i32,
+        v: bool,
+        s: i32,
+    },
+
+    CellFormulaNumber {
+        f: i32,
+        v: f64,
+        s: i32,
+    },
     // always inline string
-    #[serde(rename = "str")]
-    CellFormulaString { f: i32, v: String, s: i32 },
-    #[serde(rename = "fe")]
+    CellFormulaString {
+        f: i32,
+        v: String,
+        s: i32,
+    },
+
     CellFormulaError {
         f: i32,
         ei: Error,
@@ -208,17 +226,16 @@ impl Default for Cell {
     }
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Encode, Decode, Debug, PartialEq, Eq, Clone)]
 pub struct Comment {
     pub text: String,
     pub author_name: String,
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub author_id: Option<String>,
     pub cell_ref: String,
 }
 
 // ECMA-376-1:2016 section 18.5.1.2
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Encode, Decode, Debug, PartialEq, Eq, Clone)]
 pub struct Table {
     pub name: String,
     pub display_name: String,
@@ -226,34 +243,24 @@ pub struct Table {
     pub reference: String,
     pub totals_row_count: u32,
     pub header_row_count: u32,
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub header_row_dxf_id: Option<u32>,
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub data_dxf_id: Option<u32>,
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub totals_row_dxf_id: Option<u32>,
     pub columns: Vec<TableColumn>,
     pub style_info: TableStyleInfo,
-    #[serde(default = "default_as_false")]
-    #[serde(skip_serializing_if = "is_false")]
     pub has_filters: bool,
 }
 
 // totals_row_label vs totals_row_function might be mutually exclusive. Use an enum?
 // the totals_row_function is an enum not String methinks
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Encode, Decode, Debug, PartialEq, Eq, Clone)]
 pub struct TableColumn {
     pub id: u32,
     pub name: String,
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub totals_row_label: Option<String>,
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub header_row_dxf_id: Option<u32>,
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub data_dxf_id: Option<u32>,
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub totals_row_dxf_id: Option<u32>,
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub totals_row_function: Option<String>,
 }
 
@@ -271,25 +278,16 @@ impl Default for TableColumn {
     }
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone, Default)]
+#[derive(Encode, Decode, Debug, PartialEq, Eq, Clone, Default)]
 pub struct TableStyleInfo {
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub name: Option<String>,
-    #[serde(default = "default_as_false")]
-    #[serde(skip_serializing_if = "is_false")]
     pub show_first_column: bool,
-    #[serde(default = "default_as_false")]
-    #[serde(skip_serializing_if = "is_false")]
     pub show_last_column: bool,
-    #[serde(default = "default_as_false")]
-    #[serde(skip_serializing_if = "is_false")]
     pub show_row_stripes: bool,
-    #[serde(default = "default_as_false")]
-    #[serde(skip_serializing_if = "is_false")]
     pub show_column_stripes: bool,
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Encode, Decode, Debug, PartialEq, Eq, Clone)]
 pub struct Styles {
     pub num_fmts: Vec<NumFmt>,
     pub fonts: Vec<Font>,
@@ -314,8 +312,9 @@ impl Default for Styles {
     }
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Serialize, Deserialize, Encode, Decode, Debug, PartialEq, Eq, Clone)]
 pub struct Style {
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub alignment: Option<Alignment>,
     pub num_fmt: String,
     pub fill: Fill,
@@ -324,7 +323,7 @@ pub struct Style {
     pub quote_prefix: bool,
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Encode, Decode, Debug, PartialEq, Eq, Clone)]
 pub struct NumFmt {
     pub num_fmt_id: i32,
     pub format_code: String,
@@ -342,7 +341,7 @@ impl Default for NumFmt {
 // ST_FontScheme simple type (§18.18.33).
 // Usually major fonts are used for styles like headings,
 // and minor fonts are used for body and paragraph text.
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Serialize, Deserialize, Encode, Decode, Debug, PartialEq, Eq, Clone)]
 #[serde(rename_all = "lowercase")]
 #[derive(Default)]
 pub enum FontScheme {
@@ -362,7 +361,7 @@ impl Display for FontScheme {
     }
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Serialize, Deserialize, Encode, Decode, Debug, PartialEq, Eq, Clone)]
 pub struct Font {
     #[serde(default = "default_as_false")]
     #[serde(skip_serializing_if = "is_false")]
@@ -405,7 +404,7 @@ impl Default for Font {
 }
 
 // TODO: Maybe use an enum for the pattern_type values here?
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Serialize, Deserialize, Encode, Decode, Debug, PartialEq, Eq, Clone)]
 pub struct Fill {
     pub pattern_type: String,
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -424,7 +423,7 @@ impl Default for Fill {
     }
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Serialize, Deserialize, Encode, Decode, Debug, PartialEq, Eq, Clone)]
 #[serde(rename_all = "lowercase")]
 pub enum HorizontalAlignment {
     Center,
@@ -466,7 +465,7 @@ impl Display for HorizontalAlignment {
     }
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Serialize, Deserialize, Encode, Decode, Debug, PartialEq, Eq, Clone)]
 #[serde(rename_all = "lowercase")]
 pub enum VerticalAlignment {
     Bottom,
@@ -501,7 +500,7 @@ impl Display for VerticalAlignment {
 }
 
 // 1762
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone, Default)]
+#[derive(Serialize, Deserialize, Encode, Decode, Debug, PartialEq, Eq, Clone, Default)]
 pub struct Alignment {
     #[serde(default)]
     #[serde(skip_serializing_if = "HorizontalAlignment::is_default")]
@@ -514,29 +513,17 @@ pub struct Alignment {
     pub wrap_text: bool,
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Encode, Decode, Debug, PartialEq, Eq, Clone)]
 pub struct CellStyleXfs {
     pub num_fmt_id: i32,
     pub font_id: i32,
     pub fill_id: i32,
     pub border_id: i32,
-    #[serde(default = "default_as_true")]
-    #[serde(skip_serializing_if = "is_true")]
     pub apply_number_format: bool,
-    #[serde(default = "default_as_true")]
-    #[serde(skip_serializing_if = "is_true")]
     pub apply_border: bool,
-    #[serde(default = "default_as_true")]
-    #[serde(skip_serializing_if = "is_true")]
     pub apply_alignment: bool,
-    #[serde(default = "default_as_true")]
-    #[serde(skip_serializing_if = "is_true")]
     pub apply_protection: bool,
-    #[serde(default = "default_as_true")]
-    #[serde(skip_serializing_if = "is_true")]
     pub apply_font: bool,
-    #[serde(default = "default_as_true")]
-    #[serde(skip_serializing_if = "is_true")]
     pub apply_fill: bool,
 }
 
@@ -557,39 +544,24 @@ impl Default for CellStyleXfs {
     }
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone, Default)]
+#[derive(Encode, Decode, Debug, PartialEq, Eq, Clone, Default)]
 pub struct CellXfs {
     pub xf_id: i32,
     pub num_fmt_id: i32,
     pub font_id: i32,
     pub fill_id: i32,
     pub border_id: i32,
-    #[serde(default = "default_as_false")]
-    #[serde(skip_serializing_if = "is_false")]
     pub apply_number_format: bool,
-    #[serde(default = "default_as_false")]
-    #[serde(skip_serializing_if = "is_false")]
     pub apply_border: bool,
-    #[serde(default = "default_as_false")]
-    #[serde(skip_serializing_if = "is_false")]
     pub apply_alignment: bool,
-    #[serde(default = "default_as_false")]
-    #[serde(skip_serializing_if = "is_false")]
     pub apply_protection: bool,
-    #[serde(default = "default_as_false")]
-    #[serde(skip_serializing_if = "is_false")]
     pub apply_font: bool,
-    #[serde(default = "default_as_false")]
-    #[serde(skip_serializing_if = "is_false")]
     pub apply_fill: bool,
-    #[serde(default = "default_as_false")]
-    #[serde(skip_serializing_if = "is_false")]
     pub quote_prefix: bool,
-    #[serde(skip_serializing_if = "is_default_alignment")]
     pub alignment: Option<Alignment>,
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Encode, Decode, Debug, PartialEq, Eq, Clone)]
 pub struct CellStyles {
     pub name: String,
     pub xf_id: i32,
@@ -606,7 +578,7 @@ impl Default for CellStyles {
     }
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Serialize, Deserialize, Encode, Decode, Debug, PartialEq, Eq, Clone)]
 #[serde(rename_all = "lowercase")]
 pub enum BorderStyle {
     Thin,
@@ -636,13 +608,13 @@ impl Display for BorderStyle {
     }
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
+#[derive(Serialize, Deserialize, Encode, Decode, Debug, PartialEq, Eq, Clone)]
 pub struct BorderItem {
     pub style: BorderStyle,
     pub color: Option<String>,
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone, Default)]
+#[derive(Serialize, Deserialize, Encode, Decode, Debug, PartialEq, Eq, Clone, Default)]
 pub struct Border {
     #[serde(default = "default_as_false")]
     #[serde(skip_serializing_if = "is_false")]
@@ -665,9 +637,10 @@ pub struct Border {
 /// Information need to show a sheet tab in the UI
 /// The color is serialized only if it is not Color::None
 #[derive(Serialize, Deserialize, Debug, PartialEq)]
-pub struct SheetInfo {
+pub struct SheetProperties {
     pub name: String,
     pub state: String,
     pub sheet_id: u32,
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub color: Option<String>,
 }

base/src/units.rs

@@ -86,12 +86,15 @@ fn get_units_from_format_string(num_fmt: &str) -> Option<Units> {
 
 impl Model {
     fn compute_cell_units(&self, cell_reference: &CellReferenceIndex) -> Option<Units> {
-        let style = &self.get_style_for_cell(
+        let cell_style_res = &self.get_style_for_cell(
             cell_reference.sheet,
             cell_reference.row,
             cell_reference.column,
         );
-        get_units_from_format_string(&style.num_fmt)
+        match cell_style_res {
+            Ok(style) => get_units_from_format_string(&style.num_fmt),
+            Err(_) => None,
+        }
     }
 
     pub(crate) fn compute_node_units(

base/src/user_model/history.rs

@@ -0,0 +1,164 @@
+use std::collections::HashMap;
+
+use bitcode::{Decode, Encode};
+
+use crate::types::{Cell, Col, Row, Style};
+
+#[derive(Clone, Encode, Decode)]
+pub(crate) struct RowData {
+    pub(crate) row: Option<Row>,
+    pub(crate) data: HashMap<i32, Cell>,
+}
+
+#[derive(Clone, Encode, Decode)]
+pub(crate) struct ColumnData {
+    pub(crate) column: Option<Col>,
+    pub(crate) data: HashMap<i32, Cell>,
+}
+
+#[derive(Clone, Encode, Decode)]
+pub(crate) enum Diff {
+    // Cell diffs
+    SetCellValue {
+        sheet: u32,
+        row: i32,
+        column: i32,
+        new_value: String,
+        old_value: Box<Option<Cell>>,
+    },
+    CellClearContents {
+        sheet: u32,
+        row: i32,
+        column: i32,
+        old_value: Box<Option<Cell>>,
+    },
+    CellClearAll {
+        sheet: u32,
+        row: i32,
+        column: i32,
+        old_value: Box<Option<Cell>>,
+        old_style: Box<Style>,
+    },
+    SetCellStyle {
+        sheet: u32,
+        row: i32,
+        column: i32,
+        old_value: Box<Style>,
+        new_value: Box<Style>,
+    },
+    // Column and Row diffs
+    SetColumnWidth {
+        sheet: u32,
+        column: i32,
+        new_value: f64,
+        old_value: f64,
+    },
+    SetRowHeight {
+        sheet: u32,
+        row: i32,
+        new_value: f64,
+        old_value: f64,
+    },
+    InsertRow {
+        sheet: u32,
+        row: i32,
+    },
+    DeleteRow {
+        sheet: u32,
+        row: i32,
+        old_data: Box<RowData>,
+    },
+    InsertColumn {
+        sheet: u32,
+        column: i32,
+    },
+    DeleteColumn {
+        sheet: u32,
+        column: i32,
+        old_data: Box<ColumnData>,
+    },
+    SetFrozenRowsCount {
+        sheet: u32,
+        new_value: i32,
+        old_value: i32,
+    },
+    SetFrozenColumnsCount {
+        sheet: u32,
+        new_value: i32,
+        old_value: i32,
+    },
+    DeleteSheet {
+        sheet: u32,
+    },
+    NewSheet {
+        index: u32,
+        name: String,
+    },
+    RenameSheet {
+        index: u32,
+        old_value: String,
+        new_value: String,
+    },
+    SetSheetColor {
+        index: u32,
+        old_value: String,
+        new_value: String,
+    },
+    SetShowGridLines {
+        sheet: u32,
+        old_value: bool,
+        new_value: bool,
+    }, // FIXME: we are missing SetViewDiffs
+}
+
+pub(crate) type DiffList = Vec<Diff>;
+
+#[derive(Default)]
+pub(crate) struct History {
+    pub(crate) undo_stack: Vec<DiffList>,
+    pub(crate) redo_stack: Vec<DiffList>,
+}
+
+impl History {
+    pub fn push(&mut self, diff_list: DiffList) {
+        self.undo_stack.push(diff_list);
+        self.redo_stack = vec![];
+    }
+
+    pub fn undo(&mut self) -> Option<Vec<Diff>> {
+        match self.undo_stack.pop() {
+            Some(diff_list) => {
+                self.redo_stack.push(diff_list.clone());
+                Some(diff_list)
+            }
+            None => None,
+        }
+    }
+
+    pub fn redo(&mut self) -> Option<Vec<Diff>> {
+        match self.redo_stack.pop() {
+            Some(diff_list) => {
+                self.undo_stack.push(diff_list.clone());
+                Some(diff_list)
+            }
+            None => None,
+        }
+    }
+
+    pub fn clear(&mut self) {
+        self.redo_stack = vec![];
+        self.undo_stack = vec![];
+    }
+}
+
+#[derive(Clone, Encode, Decode)]
+pub enum DiffType {
+    Undo,
+    Redo,
+}
+
+#[derive(Clone, Encode, Decode)]
+pub struct QueueDiffs {
+    pub r#type: DiffType,
+    pub list: DiffList,
+}

base/src/user_model/mod.rs

@@ -0,0 +1,12 @@
+#![deny(missing_docs)]
+
+mod common;
+mod history;
+mod ui;
+
+pub use common::UserModel;
+
+#[cfg(test)]
+pub use ui::SelectedView;
+
+pub use common::BorderArea;

base/src/user_model/ui.rs

@@ -0,0 +1,687 @@
+#![deny(missing_docs)]
+
+use serde::{Deserialize, Serialize};
+
+use crate::expressions::utils::{is_valid_column_number, is_valid_row};
+
+use super::common::UserModel;
+
+#[derive(Serialize, Deserialize)]
+#[cfg_attr(test, derive(PartialEq, Debug))]
+pub struct SelectedView {
+    pub sheet: u32,
+    pub row: i32,
+    pub column: i32,
+    pub range: [i32; 4],
+    pub top_row: i32,
+    pub left_column: i32,
+}
+
+impl UserModel {
+    /// Returns the selected sheet index
+    pub fn get_selected_sheet(&self) -> u32 {
+        if let Some(view) = self.model.workbook.views.get(&self.model.view_id) {
+            view.sheet
+        } else {
+            0
+        }
+    }
+
+    /// Returns the selected cell
+    pub fn get_selected_cell(&self) -> (u32, i32, i32) {
+        let sheet = if let Some(view) = self.model.workbook.views.get(&self.model.view_id) {
+            view.sheet
+        } else {
+            0
+        };
+        if let Ok(worksheet) = self.model.workbook.worksheet(sheet) {
+            if let Some(view) = worksheet.views.get(&self.model.view_id) {
+                return (sheet, view.row, view.column);
+            }
+        }
+        // return a safe default
+        (0, 1, 1)
+    }
+
+    /// Returns selected view
+    pub fn get_selected_view(&self) -> SelectedView {
+        let sheet = if let Some(view) = self.model.workbook.views.get(&self.model.view_id) {
+            view.sheet
+        } else {
+            0
+        };
+        if let Ok(worksheet) = self.model.workbook.worksheet(sheet) {
+            if let Some(view) = worksheet.views.get(&self.model.view_id) {
+                return SelectedView {
+                    sheet,
+                    row: view.row,
+                    column: view.column,
+                    range: view.range,
+                    top_row: view.top_row,
+                    left_column: view.left_column,
+                };
+            }
+        }
+        // return a safe default
+        SelectedView {
+            sheet: 0,
+            row: 1,
+            column: 1,
+            range: [1, 1, 1, 1],
+            top_row: 1,
+            left_column: 1,
+        }
+    }
+
+    /// Sets the the selected sheet
+    pub fn set_selected_sheet(&mut self, sheet: u32) -> Result<(), String> {
+        if self.model.workbook.worksheet(sheet).is_err() {
+            return Err(format!("Invalid worksheet index {}", sheet));
+        }
+        if let Some(view) = self.model.workbook.views.get_mut(&0) {
+            view.sheet = sheet;
+        }
+        Ok(())
+    }
+
+    /// Sets the selected cell for the current view. Note that this also sets the selected range
+    pub fn set_selected_cell(&mut self, row: i32, column: i32) -> Result<(), String> {
+        let sheet = if let Some(view) = self.model.workbook.views.get(&self.model.view_id) {
+            view.sheet
+        } else {
+            0
+        };
+        if !is_valid_column_number(column) {
+            return Err(format!("Invalid column: '{column}'"));
+        }
+        if !is_valid_row(row) {
+            return Err(format!("Invalid row: '{row}'"));
+        }
+        if self.model.workbook.worksheet(sheet).is_err() {
+            return Err(format!("Invalid worksheet index {}", sheet));
+        }
+        if let Ok(worksheet) = self.model.workbook.worksheet_mut(sheet) {
+            if let Some(view) = worksheet.views.get_mut(&0) {
+                view.row = row;
+                view.column = column;
+                view.range = [row, column, row, column];
+            }
+        }
+        Ok(())
+    }
+
+    /// Sets the selected range. Note that the selected cell must be in one of the corners.
+    pub fn set_selected_range(
+        &mut self,
+        start_row: i32,
+        start_column: i32,
+        end_row: i32,
+        end_column: i32,
+    ) -> Result<(), String> {
+        let sheet = if let Some(view) = self.model.workbook.views.get(&self.model.view_id) {
+            view.sheet
+        } else {
+            0
+        };
+
+        if !is_valid_column_number(start_column) {
+            return Err(format!("Invalid column: '{start_column}'"));
+        }
+        if !is_valid_row(start_row) {
+            return Err(format!("Invalid row: '{start_row}'"));
+        }
+
+        if !is_valid_column_number(end_column) {
+            return Err(format!("Invalid column: '{end_column}'"));
+        }
+        if !is_valid_row(end_row) {
+            return Err(format!("Invalid row: '{end_row}'"));
+        }
+        if self.model.workbook.worksheet(sheet).is_err() {
+            return Err(format!("Invalid worksheet index {}", sheet));
+        }
+        if let Ok(worksheet) = self.model.workbook.worksheet_mut(sheet) {
+            if let Some(view) = worksheet.views.get_mut(&0) {
+                let selected_row = view.row;
+                let selected_column = view.column;
+                // The selected cells must be on one of the corners of the selected range:
+                if selected_row != start_row && selected_row != end_row {
+                    return Err(format!(
+                        "The selected cells is not in one of the corners. Row: '{}' and row range '({}, {})'",
+                        selected_row, start_row, end_row
+                    ));
+                }
+                if selected_column != start_column && selected_column != end_column {
+                    return Err(format!(
+                        "The selected cells is not in one of the corners. Column '{}' and column range '({}, {})'",
+                        selected_column, start_column, end_column
+                    ));
+                }
+                view.range = [start_row, start_column, end_row, end_column];
+            }
+        }
+        Ok(())
+    }
+
+    /// The selected range is expanded with the keyboard
+    pub fn on_expand_selected_range(&mut self, key: &str) -> Result<(), String> {
+        let (sheet, window_width, window_height) =
+            if let Some(view) = self.model.workbook.views.get(&self.model.view_id) {
+                (
+                    view.sheet,
+                    view.window_width as f64,
+                    view.window_height as f64,
+                )
+            } else {
+                return Ok(());
+            };
+        let (selected_row, selected_column, range, top_row, left_column) =
+            if let Ok(worksheet) = self.model.workbook.worksheet(sheet) {
+                if let Some(view) = worksheet.views.get(&self.model.view_id) {
+                    (
+                        view.row,
+                        view.column,
+                        view.range,
+                        view.top_row,
+                        view.left_column,
+                    )
+                } else {
+                    return Ok(());
+                }
+            } else {
+                return Ok(());
+            };
+        let [row_start, column_start, row_end, column_end] = range;
+
+        match key {
+            "ArrowRight" => {
+                if selected_column > column_start {
+                    let new_column = column_start + 1;
+                    if !(is_valid_column_number(new_column)) {
+                        return Ok(());
+                    }
+                    self.set_selected_range(row_start, new_column, row_end, column_end)?;
+                } else {
+                    let new_column = column_end + 1;
+                    if !is_valid_column_number(new_column) {
+                        return Ok(());
+                    }
+                    // if the column is not fully visible we 'scroll' right until it is
+                    let mut width = 0.0;
+                    let mut c = left_column;
+                    while c <= new_column {
+                        width += self.model.get_column_width(sheet, c)?;
+                        c += 1;
+                    }
+                    if width > window_width {
+                        self.set_top_left_visible_cell(top_row, left_column + 1)?;
+                    }
+                    self.set_selected_range(row_start, column_start, row_end, column_end + 1)?;
+                }
+            }
+            "ArrowLeft" => {
+                if selected_column < column_end {
+                    let new_column = column_end - 1;
+                    if !is_valid_column_number(new_column) {
+                        return Ok(());
+                    }
+                    if new_column < left_column {
+                        self.set_top_left_visible_cell(top_row, new_column)?;
+                    }
+                    self.set_selected_range(row_start, column_start, row_end, new_column)?;
+                } else {
+                    let new_column = column_start - 1;
+                    if !is_valid_column_number(new_column) {
+                        return Ok(());
+                    }
+                    if new_column < left_column {
+                        self.set_top_left_visible_cell(top_row, new_column)?;
+                    }
+                    self.set_selected_range(row_start, new_column, row_end, column_end)?;
+                }
+            }
+            "ArrowUp" => {
+                if selected_row < row_end {
+                    let new_row = row_end - 1;
+                    if !is_valid_row(new_row) {
+                        return Ok(());
+                    }
+                    self.set_selected_range(row_start, column_start, new_row, column_end)?;
+                } else {
+                    let new_row = row_start - 1;
+                    if !is_valid_row(new_row) {
+                        return Ok(());
+                    }
+                    if new_row < top_row {
+                        self.set_top_left_visible_cell(new_row, left_column)?;
+                    }
+                    self.set_selected_range(new_row, column_start, row_end, column_end)?;
+                }
+            }
+            "ArrowDown" => {
+                if selected_row > row_start {
+                    let new_row = row_start + 1;
+                    if !is_valid_row(new_row) {
+                        return Ok(());
+                    }
+                    self.set_selected_range(new_row, column_start, row_end, column_end)?;
+                } else {
+                    let new_row = row_end + 1;
+                    if !is_valid_row(new_row) {
+                        return Ok(());
+                    }
+                    let mut height = 0.0;
+                    let mut r = top_row;
+                    while r <= new_row + 1 {
+                        height += self.model.get_row_height(sheet, r)?;
+                        r += 1;
+                    }
+                    if height >= window_height {
+                        self.set_top_left_visible_cell(top_row + 1, left_column)?;
+                    }
+                    self.set_selected_range(row_start, column_start, new_row, column_end)?;
+                }
+            }
+            _ => {}
+        }
+
+        Ok(())
+    }
+
+    /// Sets the value of the first visible cell
+    pub fn set_top_left_visible_cell(
+        &mut self,
+        top_row: i32,
+        left_column: i32,
+    ) -> Result<(), String> {
+        let sheet = if let Some(view) = self.model.workbook.views.get(&self.model.view_id) {
+            view.sheet
+        } else {
+            0
+        };
+
+        if !is_valid_column_number(left_column) {
+            return Err(format!("Invalid column: '{left_column}'"));
+        }
+        if !is_valid_row(top_row) {
+            return Err(format!("Invalid row: '{top_row}'"));
+        }
+        if self.model.workbook.worksheet(sheet).is_err() {
+            return Err(format!("Invalid worksheet index {}", sheet));
+        }
+        if let Ok(worksheet) = self.model.workbook.worksheet_mut(sheet) {
+            if let Some(view) = worksheet.views.get_mut(&0) {
+                view.top_row = top_row;
+                view.left_column = left_column;
+            }
+        }
+        Ok(())
+    }
+
+    /// Sets the width of the window
+    pub fn set_window_width(&mut self, window_width: f64) {
+        if let Some(view) = self.model.workbook.views.get_mut(&self.model.view_id) {
+            view.window_width = window_width as i64;
+        };
+    }
+
+    /// Gets the width of the window
+    pub fn get_window_width(&mut self) -> Result<i64, String> {
+        if let Some(view) = self.model.workbook.views.get_mut(&self.model.view_id) {
+            return Ok(view.window_width);
+        };
+        Err("View not found".to_string())
+    }
+
+    /// Sets the height of the window
+    pub fn set_window_height(&mut self, window_height: f64) {
+        if let Some(view) = self.model.workbook.views.get_mut(&self.model.view_id) {
+            view.window_height = window_height as i64;
+        };
+    }
+
+    /// Gets the height of the window
+    pub fn get_window_height(&mut self) -> Result<i64, String> {
+        if let Some(view) = self.model.workbook.views.get_mut(&self.model.view_id) {
+            return Ok(view.window_height);
+        };
+        Err("View not found".to_string())
+    }
+
+    /// User presses right arrow
+    pub fn on_arrow_right(&mut self) -> Result<(), String> {
+        let (sheet, window_width) =
+            if let Some(view) = self.model.workbook.views.get(&self.model.view_id) {
+                (view.sheet, view.window_width)
+            } else {
+                return Err("View not found".to_string());
+            };
+        let worksheet = match self.model.workbook.worksheet(sheet) {
+            Ok(s) => s,
+            Err(_) => return Err("Worksheet not found".to_string()),
+        };
+        let view = match worksheet.views.get(&self.model.view_id) {
+            Some(s) => s,
+            None => return Err("View not found".to_string()),
+        };
+        let new_column = view.column + 1;
+        if !is_valid_column_number(new_column) {
+            return Ok(());
+        }
+        // if the column is not fully visible we 'scroll' right until it is
+        let mut width = 0.0;
+        let mut column = view.left_column;
+        while column <= new_column {
+            width += self.model.get_column_width(sheet, column)?;
+            column += 1;
+        }
+        if let Ok(worksheet) = self.model.workbook.worksheet_mut(sheet) {
+            if let Some(view) = worksheet.views.get_mut(&self.model.view_id) {
+                view.column = new_column;
+                view.range = [view.row, new_column, view.row, new_column];
+                if width > window_width as f64 {
+                    view.left_column += 1;
+                }
+            }
+        }
+        Ok(())
+    }
+
+    /// User presses left arrow
+    pub fn on_arrow_left(&mut self) -> Result<(), String> {
+        let sheet = if let Some(view) = self.model.workbook.views.get(&self.model.view_id) {
+            view.sheet
+        } else {
+            return Err("View not found".to_string());
+        };
+        let worksheet = match self.model.workbook.worksheet(sheet) {
+            Ok(s) => s,
+            Err(_) => return Err("Worksheet not found".to_string()),
+        };
+        let view = match worksheet.views.get(&self.model.view_id) {
+            Some(s) => s,
+            None => return Err("View not found".to_string()),
+        };
+        let new_column = view.column - 1;
+        if !is_valid_column_number(new_column) {
+            return Ok(());
+        }
+        // if the column is not fully visible we 'scroll' right until it is
+        if let Ok(worksheet) = self.model.workbook.worksheet_mut(sheet) {
+            if let Some(view) = worksheet.views.get_mut(&self.model.view_id) {
+                view.column = new_column;
+                view.range = [view.row, new_column, view.row, new_column];
+                if new_column < view.left_column {
+                    view.left_column = new_column;
+                }
+            }
+        }
+        Ok(())
+    }
+
+    /// User presses up arrow key
+    pub fn on_arrow_up(&mut self) -> Result<(), String> {
+        let sheet = if let Some(view) = self.model.workbook.views.get(&self.model.view_id) {
+            view.sheet
+        } else {
+            return Err("View not found".to_string());
+        };
+        let worksheet = match self.model.workbook.worksheet(sheet) {
+            Ok(s) => s,
+            Err(_) => return Err("Worksheet not found".to_string()),
+        };
+        let view = match worksheet.views.get(&self.model.view_id) {
+            Some(s) => s,
+            None => return Err("View not found".to_string()),
+        };
+        let new_row = view.row - 1;
+        if !is_valid_row(new_row) {
+            return Ok(());
+        }
+        // if the column is not fully visible we 'scroll' right until it is
+        if let Ok(worksheet) = self.model.workbook.worksheet_mut(sheet) {
+            if let Some(view) = worksheet.views.get_mut(&self.model.view_id) {
+                view.row = new_row;
+                view.range = [new_row, view.column, new_row, view.column];
+                if new_row < view.top_row {
+                    view.top_row = new_row;
+                }
+            }
+        }
+        Ok(())
+    }
+
+    /// User presses down arrow key
+    pub fn on_arrow_down(&mut self) -> Result<(), String> {
+        let (sheet, window_height) =
+            if let Some(view) = self.model.workbook.views.get(&self.model.view_id) {
+                (view.sheet, view.window_height)
+            } else {
+                return Err("View not found".to_string());
+            };
+        let worksheet = match self.model.workbook.worksheet(sheet) {
+            Ok(s) => s,
+            Err(_) => return Err("Worksheet not found".to_string()),
+        };
+        let view = match worksheet.views.get(&self.model.view_id) {
+            Some(s) => s,
+            None => return Err("View not found".to_string()),
+        };
+        let new_row = view.row + 1;
+        if !is_valid_row(new_row) {
+            return Ok(());
+        }
+        // if the row is not fully visible we 'scroll' down until it is
+        let mut height = 0.0;
+        let mut row = view.top_row;
+        while row <= new_row + 1 {
+            height += self.model.get_row_height(sheet, row)?;
+            row += 1;
+        }
+        if let Ok(worksheet) = self.model.workbook.worksheet_mut(sheet) {
+            if let Some(view) = worksheet.views.get_mut(&self.model.view_id) {
+                view.row = new_row;
+                view.range = [new_row, view.column, new_row, view.column];
+                if height > window_height as f64 {
+                    view.top_row += 1;
+                }
+            }
+        }
+        Ok(())
+    }
+
+    // TODO: This function should be memoized
+    /// Returns the x-coordinate of the cell in the top left corner
+    pub fn get_scroll_x(&self) -> Result<f64, String> {
+        let sheet = if let Some(view) = self.model.workbook.views.get(&self.model.view_id) {
+            view.sheet
+        } else {
+            return Err("View not found".to_string());
+        };
+        let worksheet = match self.model.workbook.worksheet(sheet) {
+            Ok(s) => s,
+            Err(_) => return Err("Worksheet not found".to_string()),
+        };
+        let view = match worksheet.views.get(&self.model.view_id) {
+            Some(s) => s,
+            None => return Err("View not found".to_string()),
+        };
+        let mut scroll_x = 0.0;
+        for column in 1..view.left_column {
+            scroll_x += self.model.get_column_width(sheet, column)?;
+        }
+        Ok(scroll_x)
+    }
+
+    // TODO: This function should be memoized
+    /// Returns the y-coordinate of the cell in the top left corner
+    pub fn get_scroll_y(&self) -> Result<f64, String> {
+        let sheet = if let Some(view) = self.model.workbook.views.get(&self.model.view_id) {
+            view.sheet
+        } else {
+            return Err("View not found".to_string());
+        };
+        let worksheet = match self.model.workbook.worksheet(sheet) {
+            Ok(s) => s,
+            Err(_) => return Err("Worksheet not found".to_string()),
+        };
+        let view = match worksheet.views.get(&self.model.view_id) {
+            Some(s) => s,
+            None => return Err("View not found".to_string()),
+        };
+        let mut scroll_y = 0.0;
+        for row in 1..view.top_row {
+            scroll_y += self.model.get_row_height(sheet, row)?;
+        }
+        Ok(scroll_y)
+    }
+
+    /// User presses page down.
+    /// The `top_row` is now the first row that is not fully visible
+    pub fn on_page_down(&mut self) -> Result<(), String> {
+        let (sheet, window_height) =
+            if let Some(view) = self.model.workbook.views.get(&self.model.view_id) {
+                (view.sheet, view.window_height)
+            } else {
+                return Err("View not found".to_string());
+            };
+        let worksheet = match self.model.workbook.worksheet(sheet) {
+            Ok(s) => s,
+            Err(_) => return Err("Worksheet not found".to_string()),
+        };
+        let view = match worksheet.views.get(&self.model.view_id) {
+            Some(s) => s,
+            None => return Err("View not found".to_string()),
+        };
+        let mut last_row = view.top_row;
+        let mut height = self.model.get_row_height(sheet, last_row)?;
+        while height <= window_height as f64 {
+            last_row += 1;
+            height += self.model.get_row_height(sheet, last_row)?;
+        }
+        if !is_valid_row(last_row) {
+            return Ok(());
+        }
+        let row_delta = view.row - view.top_row;
+        if let Ok(worksheet) = self.model.workbook.worksheet_mut(sheet) {
+            if let Some(view) = worksheet.views.get_mut(&self.model.view_id) {
+                view.top_row = last_row;
+                view.row = view.top_row + row_delta;
+                view.range = [view.row, view.column, view.row, view.column];
+            }
+        }
+        Ok(())
+    }
+
+    /// On page up. tis needs to be the inverse of page down
+    pub fn on_page_up(&mut self) -> Result<(), String> {
+        let (sheet, window_height) =
+            if let Some(view) = self.model.workbook.views.get(&self.model.view_id) {
+                (view.sheet, view.window_height as f64)
+            } else {
+                return Err("View not found".to_string());
+            };
+        let worksheet = match self.model.workbook.worksheet(sheet) {
+            Ok(s) => s,
+            Err(_) => return Err("Worksheet not found".to_string()),
+        };
+        let view = match worksheet.views.get(&self.model.view_id) {
+            Some(s) => s,
+            None => return Err("View not found".to_string()),
+        };
+
+        let mut first_row = view.top_row;
+        let mut height = self.model.get_row_height(sheet, first_row)?;
+        while height <= window_height && first_row > 1 {
+            first_row -= 1;
+            height += self.model.get_row_height(sheet, first_row)?;
+        }
+
+        let row_delta = view.row - view.top_row;
+        if let Ok(worksheet) = self.model.workbook.worksheet_mut(sheet) {
+            if let Some(view) = worksheet.views.get_mut(&self.model.view_id) {
+                view.top_row = first_row;
+                view.row = view.top_row + row_delta;
+                view.range = [view.row, view.column, view.row, view.column];
+            }
+        }
+        Ok(())
+    }
+
+    /// We extend the selection to cell (target_row, target_column)
+    pub fn on_area_selecting(&mut self, target_row: i32, target_column: i32) -> Result<(), String> {
+        let (sheet, window_width, window_height) =
+            if let Some(view) = self.model.workbook.views.get(&self.model.view_id) {
+                (
+                    view.sheet,
+                    view.window_width as f64,
+                    view.window_height as f64,
+                )
+            } else {
+                return Ok(());
+            };
+        let (selected_row, selected_column, range, top_row, left_column) =
+            if let Ok(worksheet) = self.model.workbook.worksheet(sheet) {
+                if let Some(view) = worksheet.views.get(&self.model.view_id) {
+                    (
+                        view.row,
+                        view.column,
+                        view.range,
+                        view.top_row,
+                        view.left_column,
+                    )
+                } else {
+                    return Ok(());
+                }
+            } else {
+                return Ok(());
+            };
+        let [row_start, column_start, _row_end, _column_end] = range;
+
+        let mut new_left_column = left_column;
+        if target_column >= selected_column {
+            let mut width = 0.0;
+            let mut column = left_column;
+            while column <= target_column {
+                width += self.model.get_column_width(sheet, column)?;
+                column += 1;
+            }
+
+            while width > window_width {
+                width -= self.model.get_column_width(sheet, new_left_column)?;
+                new_left_column += 1;
+            }
+        } else if target_column < new_left_column {
+            new_left_column = target_column;
+        }
+        let mut new_top_row = top_row;
+        if target_row >= selected_row {
+            let mut height = 0.0;
+            let mut row = top_row;
+            while row <= target_row {
+                height += self.model.get_row_height(sheet, row)?;
+                row += 1;
+            }
+            while height > window_height {
+                height -= self.model.get_row_height(sheet, new_top_row)?;
+                new_top_row += 1;
+            }
+        } else if target_row < new_top_row {
+            new_top_row = target_row;
+        }
+
+        if let Ok(worksheet) = self.model.workbook.worksheet_mut(sheet) {
+            if let Some(view) = worksheet.views.get_mut(&self.model.view_id) {
+                view.range = [row_start, column_start, target_row, target_column];
+                if new_top_row != top_row {
+                    view.top_row = new_top_row;
+                }
+                if new_left_column != left_column {
+                    view.left_column = new_left_column;
+                }
+            }
+        }
+
+        Ok(())
+    }
+}

base/src/workbook.rs

@@ -27,16 +27,4 @@ impl Workbook {
             .get_mut(worksheet_index as usize)
             .ok_or_else(|| "Invalid sheet index".to_string())
     }
-
-    pub fn get_worksheets_info(&self) -> Vec<SheetInfo> {
-        self.worksheets
-            .iter()
-            .map(|worksheet| SheetInfo {
-                name: worksheet.get_name(),
-                state: worksheet.state.to_string(),
-                color: worksheet.color.clone(),
-                sheet_id: worksheet.sheet_id,
-            })
-            .collect()
-    }
 }

base/src/worksheet.rs

@@ -42,7 +42,17 @@ impl Worksheet {
         self.sheet_data.get_mut(&row)?.get_mut(&column)
     }
 
-    fn update_cell(&mut self, row: i32, column: i32, new_cell: Cell) {
+    pub(crate) fn update_cell(
+        &mut self,
+        row: i32,
+        column: i32,
+        new_cell: Cell,
+    ) -> Result<(), String> {
+        // validate row and column arg before updating cell of worksheet
+        if !is_valid_row(row) || !is_valid_column_number(column) {
+            return Err("Incorrect row or column".to_string());
+        }
+
         match self.sheet_data.get_mut(&row) {
             Some(column_data) => match column_data.get(&column) {
                 Some(_cell) => {
@@ -58,6 +68,7 @@ impl Worksheet {
                 self.sheet_data.insert(row, column_data);
             }
         }
+        Ok(())
     }
 
     // TODO [MVP]: Pass the cell style from the model
@@ -68,9 +79,8 @@ impl Worksheet {
             if row.r == row_index {
                 if row.custom_format {
                     return row.s;
-                } else {
-                    break;
                 }
+                break;
             }
         }
         let cols = &self.cols;
@@ -106,64 +116,8 @@ impl Worksheet {
     }
 
     pub fn set_column_style(&mut self, column: i32, style_index: i32) -> Result<(), String> {
-        let cols = &mut self.cols;
-        let col = Col {
-            min: column,
-            max: column,
-            width: constants::DEFAULT_COLUMN_WIDTH / constants::COLUMN_WIDTH_FACTOR,
-            custom_width: true,
-            style: Some(style_index),
-        };
-        let mut index = 0;
-        let mut split = false;
-        for c in cols.iter_mut() {
-            let min = c.min;
-            let max = c.max;
-            if min <= column && column <= max {
-                if min == column && max == column {
-                    c.style = Some(style_index);
-                    return Ok(());
-                } else {
-                    // We need to split the result
-                    split = true;
-                    break;
-                }
-            }
-            if column < min {
-                // We passed, we should insert at index
-                break;
-            }
-            index += 1;
-        }
-        if split {
-            let min = cols[index].min;
-            let max = cols[index].max;
-            let pre = Col {
-                min,
-                max: column - 1,
-                width: cols[index].width,
-                custom_width: cols[index].custom_width,
-                style: cols[index].style,
-            };
-            let post = Col {
-                min: column + 1,
-                max,
-                width: cols[index].width,
-                custom_width: cols[index].custom_width,
-                style: cols[index].style,
-            };
-            cols.remove(index);
-            if column != max {
-                cols.insert(index, post);
-            }
-            cols.insert(index, col);
-            if column != min {
-                cols.insert(index, pre);
-            }
-        } else {
-            cols.insert(index, col);
-        }
-        Ok(())
+        let width = constants::DEFAULT_COLUMN_WIDTH / constants::COLUMN_WIDTH_FACTOR;
+        self.set_column_width_and_style(column, width, Some(style_index))
     }
 
     pub fn set_row_style(&mut self, row: i32, style_index: i32) -> Result<(), String> {
@@ -185,59 +139,101 @@ impl Worksheet {
         Ok(())
     }
 
-    pub fn set_cell_style(&mut self, row: i32, column: i32, style_index: i32) {
+    pub fn set_cell_style(
+        &mut self,
+        row: i32,
+        column: i32,
+        style_index: i32,
+    ) -> Result<(), String> {
         match self.cell_mut(row, column) {
             Some(cell) => {
                 cell.set_style(style_index);
             }
             None => {
-                self.set_cell_empty_with_style(row, column, style_index);
+                self.cell_clear_contents_with_style(row, column, style_index)?;
             }
         }
+        Ok(())
 
         // TODO: cleanup check if the old cell style is still in use
     }
 
-    pub fn set_cell_with_formula(&mut self, row: i32, column: i32, index: i32, style: i32) {
+    pub fn set_cell_with_formula(
+        &mut self,
+        row: i32,
+        column: i32,
+        index: i32,
+        style: i32,
+    ) -> Result<(), String> {
         let cell = Cell::new_formula(index, style);
-        self.update_cell(row, column, cell);
+        self.update_cell(row, column, cell)
     }
 
-    pub fn set_cell_with_number(&mut self, row: i32, column: i32, value: f64, style: i32) {
+    pub fn set_cell_with_number(
+        &mut self,
+        row: i32,
+        column: i32,
+        value: f64,
+        style: i32,
+    ) -> Result<(), String> {
         let cell = Cell::new_number(value, style);
-        self.update_cell(row, column, cell);
+        self.update_cell(row, column, cell)
     }
 
-    pub fn set_cell_with_string(&mut self, row: i32, column: i32, index: i32, style: i32) {
+    pub fn set_cell_with_string(
+        &mut self,
+        row: i32,
+        column: i32,
+        index: i32,
+        style: i32,
+    ) -> Result<(), String> {
         let cell = Cell::new_string(index, style);
-        self.update_cell(row, column, cell);
+        self.update_cell(row, column, cell)
     }
 
-    pub fn set_cell_with_boolean(&mut self, row: i32, column: i32, value: bool, style: i32) {
+    pub fn set_cell_with_boolean(
+        &mut self,
+        row: i32,
+        column: i32,
+        value: bool,
+        style: i32,
+    ) -> Result<(), String> {
         let cell = Cell::new_boolean(value, style);
-        self.update_cell(row, column, cell);
+        self.update_cell(row, column, cell)
     }
 
-    pub fn set_cell_with_error(&mut self, row: i32, column: i32, error: Error, style: i32) {
+    pub fn set_cell_with_error(
+        &mut self,
+        row: i32,
+        column: i32,
+        error: Error,
+        style: i32,
+    ) -> Result<(), String> {
         let cell = Cell::new_error(error, style);
-        self.update_cell(row, column, cell);
+        self.update_cell(row, column, cell)
     }
 
-    pub fn set_cell_empty(&mut self, row: i32, column: i32) {
+    pub fn cell_clear_contents(&mut self, row: i32, column: i32) -> Result<(), String> {
         let s = self.get_style(row, column);
         let cell = Cell::EmptyCell { s };
-        self.update_cell(row, column, cell);
+        self.update_cell(row, column, cell)
     }
 
-    pub fn set_cell_empty_with_style(&mut self, row: i32, column: i32, style: i32) {
+    pub fn cell_clear_contents_with_style(
+        &mut self,
+        row: i32,
+        column: i32,
+        style: i32,
+    ) -> Result<(), String> {
         let cell = Cell::EmptyCell { s: style };
-        self.update_cell(row, column, cell);
+        self.update_cell(row, column, cell)
     }
 
     pub fn set_frozen_rows(&mut self, frozen_rows: i32) -> Result<(), String> {
         if frozen_rows < 0 {
             return Err("Frozen rows cannot be negative".to_string());
-        } else if frozen_rows >= constants::LAST_ROW {
+        }
+        if frozen_rows >= constants::LAST_ROW {
             return Err("Too many rows".to_string());
         }
         self.frozen_rows = frozen_rows;
@@ -247,7 +243,8 @@ impl Worksheet {
     pub fn set_frozen_columns(&mut self, frozen_columns: i32) -> Result<(), String> {
         if frozen_columns < 0 {
             return Err("Frozen columns cannot be negative".to_string());
-        } else if frozen_columns >= constants::LAST_COLUMN {
+        }
+        if frozen_columns >= constants::LAST_COLUMN {
             return Err("Too many columns".to_string());
         }
         self.frozen_columns = frozen_columns;
@@ -281,11 +278,21 @@ impl Worksheet {
         });
         Ok(())
     }
+
     /// Changes the width of a column.
     ///   * If the column does not a have a width we simply add it
     ///   * If it has, it might be part of a range and we ned to split the range.
     /// Fails if column index is outside allowed range.
     pub fn set_column_width(&mut self, column: i32, width: f64) -> Result<(), String> {
+        self.set_column_width_and_style(column, width, None)
+    }
+
+    pub(crate) fn set_column_width_and_style(
+        &mut self,
+        column: i32,
+        width: f64,
+        style: Option<i32>,
+    ) -> Result<(), String> {
         if !is_valid_column_number(column) {
             return Err(format!("Column number '{column}' is not valid."));
         }
@@ -295,7 +302,7 @@ impl Worksheet {
             max: column,
             width: width / constants::COLUMN_WIDTH_FACTOR,
             custom_width: true,
-            style: None,
+            style,
         };
         let mut index = 0;
         let mut split = false;
@@ -306,11 +313,9 @@ impl Worksheet {
                 if min == column && max == column {
                     c.width = width / constants::COLUMN_WIDTH_FACTOR;
                     return Ok(());
-                } else {
-                    // We need to split the result
-                    split = true;
-                    break;
                 }
+                split = true;
+                break;
             }
             if column < min {
                 // We passed, we should insert at index
@@ -351,7 +356,7 @@ impl Worksheet {
     }
 
     /// Return the width of a column in pixels
-    pub fn column_width(&self, column: i32) -> Result<f64, String> {
+    pub fn get_column_width(&self, column: i32) -> Result<f64, String> {
         if !is_valid_column_number(column) {
             return Err(format!("Column number '{column}' is not valid."));
         }
@@ -363,9 +368,8 @@ impl Worksheet {
             if column >= min && column <= max {
                 if col.custom_width {
                     return Ok(col.width * constants::COLUMN_WIDTH_FACTOR);
-                } else {
-                    break;
                 }
+                break;
             }
         }
         Ok(constants::DEFAULT_COLUMN_WIDTH)