Auto merge of #10350 - mbrubeck:selection-chars, r=SimonSapin

Fix some char/byte bugs in textinput

Fixes #9569. r? @SimonSapin or @Ms2ger

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tests/unit/script/textinput.rs

@@ -117,6 +117,55 @@ fn test_single_line_textinput_with_max_length_doesnt_allow_appending_characters_
     assert_eq!(textinput.get_content(), "atooe");
 }
 
+#[test]
+fn test_single_line_textinput_with_max_length_multibyte() {
+    let mut textinput = TextInput::new(
+        Lines::Single,
+        DOMString::from(""),
+        DummyClipboardContext::new(""),
+        Some(2)
+    );
+
+    textinput.insert_char('á');
+    assert_eq!(textinput.get_content(), "á");
+    textinput.insert_char('é');
+    assert_eq!(textinput.get_content(), "áé");
+    textinput.insert_char('i');
+    assert_eq!(textinput.get_content(), "áé");
+}
+
+#[test]
+fn test_single_line_textinput_with_max_length_multi_code_unit() {
+    let mut textinput = TextInput::new(
+        Lines::Single,
+        DOMString::from(""),
+        DummyClipboardContext::new(""),
+        Some(3)
+    );
+
+    textinput.insert_char('\u{10437}');
+    assert_eq!(textinput.get_content(), "\u{10437}");
+    textinput.insert_char('\u{10437}');
+    assert_eq!(textinput.get_content(), "\u{10437}");
+    textinput.insert_char('x');
+    assert_eq!(textinput.get_content(), "\u{10437}x");
+    textinput.insert_char('x');
+    assert_eq!(textinput.get_content(), "\u{10437}x");
+}
+
+#[test]
+fn test_single_line_textinput_with_max_length_inside_char() {
+    let mut textinput = TextInput::new(
+        Lines::Single,
+        DOMString::from("\u{10437}"),
+        DummyClipboardContext::new(""),
+        Some(1)
+    );
+
+    textinput.insert_char('x');
+    assert_eq!(textinput.get_content(), "\u{10437}");
+}
+
 #[test]
 fn test_single_line_textinput_with_max_length_doesnt_allow_appending_characters_after_max_length_is_reached() {
     let mut textinput = TextInput::new(
@@ -206,6 +255,15 @@ fn test_textinput_replace_selection() {
     assert_eq!(textinput.get_content(), "abxyzefg");
 }
 
+#[test]
+fn test_textinput_replace_selection_multibyte_char() {
+    let mut textinput = text_input(Lines::Single, "é");
+    textinput.adjust_horizontal_by_one(Direction::Forward, Selection::Selected);
+
+    textinput.replace_selection(DOMString::from("e"));
+    assert_eq!(textinput.get_content(), "e");
+}
+
 #[test]
 fn test_textinput_current_line_length() {
     let mut textinput = text_input(Lines::Multiple, "abc\nde\nf");
@@ -235,6 +293,19 @@ fn test_textinput_adjust_vertical() {
     assert_eq!(textinput.edit_point.index, 1);
 }
 
+#[test]
+fn test_textinput_adjust_vertical_multibyte() {
+    let mut textinput = text_input(Lines::Multiple, "áé\nae");
+
+    textinput.adjust_horizontal_by_one(Direction::Forward, Selection::NotSelected);
+    assert_eq!(textinput.edit_point.line, 0);
+    assert_eq!(textinput.edit_point.index, 2);
+
+    textinput.adjust_vertical(1, Selection::NotSelected);
+    assert_eq!(textinput.edit_point.line, 1);
+    assert_eq!(textinput.edit_point.index, 1);
+}
+
 #[test]
 fn test_textinput_adjust_horizontal() {
     let mut textinput = text_input(Lines::Multiple, "abc\nde\nf");