auto merge of #4569 : donaldpipowitch/servo/add-unit-tests-for-textinput, r=jdm

Please bear with me. This is the first Rust code I've ever written and the first systems programming language I've ever used.

I've added unit tests for all methods of TextInput ( - except `handle_keydown`). I probably didn't cover all cases - I don't know if this is a real requirement until we have some coverage tools which identify all missing cases easily.
If someone could show me how to create a `KeyboardEvent` easily I could add another test for `handle_keydown`.

Other questions:
1. Running `$ time ./mach test-unit -c script test_textinput` takes `3m29.536s` on my MacBook Pro (2012). Any hints on speeding this up?
2. Who is responsible for the feedback of the unit tests? It would be nice if the output could be colored (e.g. make `11 passed;` green, `0 failed;` red and so on.)

components/script/textinput.rs

@@ -130,7 +130,7 @@ impl TextInput {
 
     fn replace_selection(&mut self, insert: String) {
         let (begin, end) = self.get_sorted_selection();
-        self.selection_begin = None;
+        self.clear_selection();
 
         let new_lines = {
             let prefix = self.lines[begin.line].slice_chars(0, begin.index);
@@ -181,7 +181,7 @@ impl TextInput {
                 self.selection_begin = Some(self.edit_point);
             }
         } else {
-            self.selection_begin = None;
+            self.clear_selection();
         }
 
         assert!(self.edit_point.line < self.lines.len());
@@ -214,7 +214,7 @@ impl TextInput {
             if self.selection_begin.is_some() {
                 let (begin, end) = self.get_sorted_selection();
                 self.edit_point = if adjust < 0 {begin} else {end};
-                self.selection_begin = None;
+                self.clear_selection();
                 return
             }
         }
@@ -262,6 +262,11 @@ impl TextInput {
         self.edit_point.index = self.lines[last_line].char_len();
     }
 
+    /// Remove the current selection.
+    fn clear_selection(&mut self) {
+        self.selection_begin = None;
+    }
+
     /// Process a given `KeyboardEvent` and return an action for the caller to execute.
     pub fn handle_keydown(&mut self, event: JSRef<KeyboardEvent>) -> KeyReaction {
         //A simple way to convert an event to a selection
@@ -361,3 +366,160 @@ impl TextInput {
         }
     }
 }
+
+#[test]
+fn test_textinput_delete_char() {
+    let mut textinput = TextInput::new(Lines::Single, "abcdefg".into_string());
+    textinput.adjust_horizontal(2, Selection::NotSelected);
+    textinput.delete_char(DeleteDir::Backward);
+    assert_eq!(textinput.get_content().as_slice(), "acdefg");
+
+    textinput.delete_char(DeleteDir::Forward);
+    assert_eq!(textinput.get_content().as_slice(), "adefg");
+
+    textinput.adjust_horizontal(2, Selection::Selected);
+    textinput.delete_char(DeleteDir::Forward);
+    assert_eq!(textinput.get_content().as_slice(), "afg");
+}
+
+#[test]
+fn test_textinput_insert_char() {
+    let mut textinput = TextInput::new(Lines::Single, "abcdefg".into_string());
+    textinput.adjust_horizontal(2, Selection::NotSelected);
+    textinput.insert_char('a');
+    assert_eq!(textinput.get_content().as_slice(), "abacdefg");
+
+    textinput.adjust_horizontal(2, Selection::Selected);
+    textinput.insert_char('b');
+    assert_eq!(textinput.get_content().as_slice(), "ababefg");
+}
+
+#[test]
+fn test_textinput_get_sorted_selection() {
+    let mut textinput = TextInput::new(Lines::Single, "abcdefg".into_string());
+    textinput.adjust_horizontal(2, Selection::NotSelected);
+    textinput.adjust_horizontal(2, Selection::Selected);
+    let (begin, end) = textinput.get_sorted_selection();
+    assert_eq!(begin.index, 2);
+    assert_eq!(end.index, 4);
+
+    textinput.clear_selection();
+
+    textinput.adjust_horizontal(-2, Selection::Selected);
+    let (begin, end) = textinput.get_sorted_selection();
+    assert_eq!(begin.index, 2);
+    assert_eq!(end.index, 4);
+}
+
+#[test]
+fn test_textinput_replace_selection() {
+    let mut textinput = TextInput::new(Lines::Single, "abcdefg".into_string());
+    textinput.adjust_horizontal(2, Selection::NotSelected);
+    textinput.adjust_horizontal(2, Selection::Selected);
+
+    textinput.replace_selection("xyz".into_string());
+    assert_eq!(textinput.get_content().as_slice(), "abxyzefg");
+}
+
+#[test]
+fn test_textinput_current_line_length() {
+    let mut textinput = TextInput::new(Lines::Multiple, "abc\nde\nf".into_string());
+    assert_eq!(textinput.current_line_length(), 3);
+
+    textinput.adjust_vertical(1, Selection::NotSelected);
+    assert_eq!(textinput.current_line_length(), 2);
+
+    textinput.adjust_vertical(1, Selection::NotSelected);
+    assert_eq!(textinput.current_line_length(), 1);
+}
+
+#[test]
+fn test_textinput_adjust_vertical() {
+    let mut textinput = TextInput::new(Lines::Multiple, "abc\nde\nf".into_string());
+    textinput.adjust_horizontal(3, Selection::NotSelected);
+    textinput.adjust_vertical(1, Selection::NotSelected);
+    assert_eq!(textinput.edit_point.line, 1);
+    assert_eq!(textinput.edit_point.index, 2);
+
+    textinput.adjust_vertical(-1, Selection::NotSelected);
+    assert_eq!(textinput.edit_point.line, 0);
+    assert_eq!(textinput.edit_point.index, 2);
+
+    textinput.adjust_vertical(2, Selection::NotSelected);
+    assert_eq!(textinput.edit_point.line, 2);
+    assert_eq!(textinput.edit_point.index, 1);
+}
+
+#[test]
+fn test_textinput_adjust_horizontal() {
+    let mut textinput = TextInput::new(Lines::Multiple, "abc\nde\nf".into_string());
+    textinput.adjust_horizontal(4, Selection::NotSelected);
+    assert_eq!(textinput.edit_point.line, 1);
+    assert_eq!(textinput.edit_point.index, 0);
+
+    textinput.adjust_horizontal(1, Selection::NotSelected);
+    assert_eq!(textinput.edit_point.line, 1);
+    assert_eq!(textinput.edit_point.index, 1);
+
+    textinput.adjust_horizontal(2, Selection::NotSelected);
+    assert_eq!(textinput.edit_point.line, 2);
+    assert_eq!(textinput.edit_point.index, 0);
+
+    textinput.adjust_horizontal(-1, Selection::NotSelected);
+    assert_eq!(textinput.edit_point.line, 1);
+    assert_eq!(textinput.edit_point.index, 2);
+}
+
+#[test]
+fn test_textinput_handle_return() {
+    let mut single_line_textinput = TextInput::new(Lines::Single, "abcdef".into_string());
+    single_line_textinput.adjust_horizontal(3, Selection::NotSelected);
+    single_line_textinput.handle_return();
+    assert_eq!(single_line_textinput.get_content().as_slice(), "abcdef");
+
+    let mut multi_line_textinput = TextInput::new(Lines::Multiple, "abcdef".into_string());
+    multi_line_textinput.adjust_horizontal(3, Selection::NotSelected);
+    multi_line_textinput.handle_return();
+    assert_eq!(multi_line_textinput.get_content().as_slice(), "abc\ndef");
+}
+
+#[test]
+fn test_textinput_select_all() {
+    let mut textinput = TextInput::new(Lines::Multiple, "abc\nde\nf".into_string());
+    assert_eq!(textinput.edit_point.line, 0);
+    assert_eq!(textinput.edit_point.index, 0);
+
+    textinput.select_all();
+    assert_eq!(textinput.edit_point.line, 2);
+    assert_eq!(textinput.edit_point.index, 1);
+}
+
+#[test]
+fn test_textinput_get_content() {
+    let single_line_textinput = TextInput::new(Lines::Single, "abcdefg".into_string());
+    assert_eq!(single_line_textinput.get_content().as_slice(), "abcdefg");
+
+    let multi_line_textinput = TextInput::new(Lines::Multiple, "abc\nde\nf".into_string());
+    assert_eq!(multi_line_textinput.get_content().as_slice(), "abc\nde\nf");
+}
+
+#[test]
+fn test_textinput_set_content() {
+    let mut textinput = TextInput::new(Lines::Multiple, "abc\nde\nf".into_string());
+    assert_eq!(textinput.get_content().as_slice(), "abc\nde\nf");
+
+    textinput.set_content("abc\nf".into_string());
+    assert_eq!(textinput.get_content().as_slice(), "abc\nf");
+
+    assert_eq!(textinput.edit_point.line, 0);
+    assert_eq!(textinput.edit_point.index, 0);
+    textinput.adjust_horizontal(3, Selection::Selected);
+    assert_eq!(textinput.edit_point.line, 0);
+    assert_eq!(textinput.edit_point.index, 3);
+    textinput.set_content("de".into_string());
+    assert_eq!(textinput.get_content().as_slice(), "de");
+    assert_eq!(textinput.edit_point.line, 0);
+    // FIXME: https://github.com/servo/servo/issues/4622.
+    assert_eq!(textinput.edit_point.index, 1);
+}
+