Refactored the HorizontallyScrollableText struct to handle Unicode strings more uniformly and to not rely on byte boundaries but instead to rely on Unicode char boundaries

src/models/mod.rs

@@ -270,14 +270,49 @@ impl HorizontallyScrollableText {
 
   pub fn pop(&mut self) {
     if *self.offset.borrow() < self.len() {
-      self.text.remove(self.len() - *self.offset.borrow() - 1);
+      let (index, _) = self
+        .text
+        .chars()
+        .enumerate()
+        .nth(self.len() - *self.offset.borrow() - 1)
+        .unwrap();
+      self.text = self
+        .text
+        .chars()
+        .enumerate()
+        .filter(|(idx, _)| *idx != index)
+        .map(|tuple| tuple.1)
+        .collect();
     }
   }
 
   pub fn push(&mut self, character: char) {
-    self
-      .text
-      .insert(self.len() - *self.offset.borrow(), character);
+    if self.text.is_empty() {
+      self.text.push(character);
+    } else {
+      let index = self.len() - *self.offset.borrow();
+
+      if index == self.len() {
+        self.text.push(character);
+      } else {
+        let mut new_text = String::new();
+        self
+          .text
+          .chars()
+          .collect::<Vec<char>>()
+          .iter()
+          .enumerate()
+          .for_each(|(idx, &c)| {
+            if idx == index {
+              new_text.push(character);
+            }
+
+            new_text.push(c);
+          });
+
+        self.text = new_text;
+      }
+    }
   }
 }
 

src/models/model_tests.rs

@@ -340,10 +340,11 @@ mod tests {
 
   #[test]
   fn test_horizontally_scrollable_text_len() {
-    let test_text = "우리 생애 최고의 해 The.Best";
+    let test_text = "우리 생애 최고의 해Test.Text";
     let horizontally_scrollable_text = HorizontallyScrollableText::new(test_text.to_owned());
 
     assert_eq!(horizontally_scrollable_text.len(), 20);
+    assert_eq!(horizontally_scrollable_text.text.len(), 36);
     assert_str_eq!(horizontally_scrollable_text.text, test_text);
   }
 
@@ -367,6 +368,26 @@ mod tests {
     );
   }
 
+  #[test]
+  fn test_horizontally_scrollable_text_scroll_text_left_uses_len_method() {
+    let horizontally_scrollable_text = HorizontallyScrollableText::from("우리");
+
+    horizontally_scrollable_text.scroll_left();
+
+    assert_eq!(*horizontally_scrollable_text.offset.borrow(), 1);
+    assert_str_eq!(horizontally_scrollable_text.to_string(), "리");
+
+    horizontally_scrollable_text.scroll_left();
+
+    assert_eq!(*horizontally_scrollable_text.offset.borrow(), 2);
+    assert_str_eq!(horizontally_scrollable_text.to_string(), "");
+
+    horizontally_scrollable_text.scroll_left();
+
+    assert_eq!(*horizontally_scrollable_text.offset.borrow(), 2);
+    assert!(horizontally_scrollable_text.to_string().is_empty());
+  }
+
   #[test]
   fn test_horizontally_scrollable_text_scroll_text_right() {
     let horizontally_scrollable_text = HorizontallyScrollableText::from("Test string");
@@ -398,6 +419,15 @@ mod tests {
     );
   }
 
+  #[test]
+  fn test_horizontally_scrollable_text_scroll_home_uses_len_method() {
+    let horizontally_scrollable_text = HorizontallyScrollableText::from("우리");
+
+    horizontally_scrollable_text.scroll_home();
+
+    assert_eq!(*horizontally_scrollable_text.offset.borrow(), 2);
+  }
+
   #[test]
   fn test_horizontally_scrollable_text_reset_offset() {
     let horizontally_scrollable_text = HorizontallyScrollableText {
@@ -411,7 +441,7 @@ mod tests {
   }
 
   #[test]
-  fn test_horizontally_scrollable_text_scroll_or_reset() {
+  fn test_horizontally_scrollable_text_scroll_left_or_reset() {
     let width = 3;
     let test_text = "Test string";
     let horizontally_scrollable_text = HorizontallyScrollableText::from(test_text);
@@ -438,7 +468,7 @@ mod tests {
   }
 
   #[test]
-  fn test_horizontally_scrollable_test_scroll_or_reset_resets_when_text_unselected() {
+  fn test_horizontally_scrollable_text_scroll_left_or_reset_resets_when_text_unselected() {
     let horizontally_scrollable_test = HorizontallyScrollableText::from("Test string");
     horizontally_scrollable_test.scroll_left();
 
@@ -449,55 +479,98 @@ mod tests {
     assert_eq!(*horizontally_scrollable_test.offset.borrow(), 0);
   }
 
+  #[test]
+  fn test_horizontally_scrollable_text_scroll_left_or_reset_uses_len_method() {
+    let horizontally_scrollable_text = HorizontallyScrollableText::from("우리");
+    let width = 1;
+
+    horizontally_scrollable_text.scroll_left_or_reset(width, true, true);
+
+    assert_eq!(*horizontally_scrollable_text.offset.borrow(), 1);
+
+    horizontally_scrollable_text.scroll_left_or_reset(width, true, true);
+
+    assert_eq!(*horizontally_scrollable_text.offset.borrow(), 2);
+
+    horizontally_scrollable_text.scroll_left_or_reset(width, true, true);
+
+    assert_eq!(*horizontally_scrollable_text.offset.borrow(), 0);
+  }
+
   #[test]
   fn test_horizontally_scrollable_text_pop() {
-    let test_text = "Test string";
+    let test_text = "Test sTrin우gs";
     let mut horizontally_scrollable_text = HorizontallyScrollableText::from(test_text);
     horizontally_scrollable_text.pop();
 
-    assert_str_eq!(horizontally_scrollable_text.text, "Test strin");
+    assert_str_eq!(horizontally_scrollable_text.text, "Test sTrin우g");
     assert_eq!(*horizontally_scrollable_text.offset.borrow(), 0);
 
     horizontally_scrollable_text.scroll_left();
     horizontally_scrollable_text.pop();
 
-    assert_str_eq!(horizontally_scrollable_text.text, "Test strn");
+    assert_str_eq!(horizontally_scrollable_text.text, "Test sTring");
     assert_eq!(*horizontally_scrollable_text.offset.borrow(), 1);
 
     horizontally_scrollable_text.scroll_right();
     horizontally_scrollable_text.scroll_right();
     horizontally_scrollable_text.pop();
 
-    assert_str_eq!(horizontally_scrollable_text.text, "Test str");
+    assert_str_eq!(horizontally_scrollable_text.text, "Test sTrin");
     assert_eq!(*horizontally_scrollable_text.offset.borrow(), 0);
 
     horizontally_scrollable_text.scroll_home();
     horizontally_scrollable_text.pop();
 
-    assert_str_eq!(horizontally_scrollable_text.text, "Test str");
-    assert_eq!(*horizontally_scrollable_text.offset.borrow(), 8);
+    assert_str_eq!(horizontally_scrollable_text.text, "Test sTrin");
+    assert_eq!(*horizontally_scrollable_text.offset.borrow(), 10);
+
+    horizontally_scrollable_text.scroll_right();
+    horizontally_scrollable_text.pop();
+
+    assert_str_eq!(horizontally_scrollable_text.text, "est sTrin");
+    assert_eq!(*horizontally_scrollable_text.offset.borrow(), 9);
+  }
+
+  #[test]
+  fn test_horizontally_scrollable_text_pop_uses_len_method() {
+    let mut horizontally_scrollable_text = HorizontallyScrollableText::from("우리");
+    horizontally_scrollable_text.pop();
+
+    assert_str_eq!(horizontally_scrollable_text.text, "우");
+    assert_eq!(*horizontally_scrollable_text.offset.borrow(), 0);
+
+    horizontally_scrollable_text.pop();
+
+    assert!(horizontally_scrollable_text.text.is_empty());
+    assert_eq!(*horizontally_scrollable_text.offset.borrow(), 0);
+
+    horizontally_scrollable_text.pop();
+
+    assert!(horizontally_scrollable_text.text.is_empty());
+    assert_eq!(*horizontally_scrollable_text.offset.borrow(), 0);
   }
 
   #[test]
   fn test_horizontally_scrollable_text_push() {
-    let test_text = "Test string";
+    let test_text = "Test stri우ng";
     let mut horizontally_scrollable_text = HorizontallyScrollableText::from(test_text);
     horizontally_scrollable_text.push('h');
 
-    assert_str_eq!(horizontally_scrollable_text.text, "Test stringh");
+    assert_str_eq!(horizontally_scrollable_text.text, "Test stri우ngh");
     assert_eq!(*horizontally_scrollable_text.offset.borrow(), 0);
 
     horizontally_scrollable_text.scroll_left();
     horizontally_scrollable_text.push('l');
 
-    assert_str_eq!(horizontally_scrollable_text.text, "Test stringlh");
+    assert_str_eq!(horizontally_scrollable_text.text, "Test stri우nglh");
     assert_eq!(*horizontally_scrollable_text.offset.borrow(), 1);
 
     horizontally_scrollable_text.scroll_right();
     horizontally_scrollable_text.scroll_right();
-    horizontally_scrollable_text.push('0');
+    horizontally_scrollable_text.push('리');
 
-    assert_str_eq!(horizontally_scrollable_text.text, "Test stringlh0");
+    assert_str_eq!(horizontally_scrollable_text.text, "Test stri우nglh리");
     assert_eq!(*horizontally_scrollable_text.offset.borrow(), 0);
   }