UPDATE: Adds 'user model' API (#27)

* bump version for documentation
* Fixes wrong doc comment
* renames old APIs to be consistent

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());
+}