FIX: Renaming a sheet with the same name doesn't do anything

Fixes #103

base/src/test/user_model/test_rename_sheet.rs

@@ -9,6 +9,13 @@ fn basic_rename() {
     assert_eq!(model.get_worksheets_properties()[0].name, "NewSheet");
 }
 
+#[test]
+fn rename_with_same_name() {
+    let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();
+    model.rename_sheet(0, "Sheet1").unwrap();
+    assert_eq!(model.get_worksheets_properties()[0].name, "Sheet1");
+}
+
 #[test]
 fn undo_redo() {
     let mut model = UserModel::new_empty("model", "en", "UTC").unwrap();