add undo/redo and macOS modifier handling to input

crates/core/tests/input.rs

@@ -6,6 +6,7 @@ use gpui_native_core::input::{Input, InputState, InputStateEvent};
 use gpui_native_theme::Theme;
 use std::cell::RefCell;
 use std::rc::Rc;
+use std::time::Duration;
 
 struct Harness {
     state: Entity<InputState>,
@@ -110,6 +111,106 @@ fn select_all_then_type_replaces_the_value() {
     assert_eq!(value(&cx, &state), "z");
 }
 
+#[cfg(target_os = "macos")]
+#[test]
+fn cmd_arrow_jumps_to_the_field_ends() {
+    let (cx, state, mut visual) = input_window("hello world", false);
+    focus(&mut visual, &state);
+
+    // Caret starts at the end; cmd-left brings it to the start.
+    visual.simulate_keystrokes("cmd-left");
+    visual.simulate_keystrokes("x");
+    assert_eq!(value(&cx, &state), "xhello world");
+
+    // cmd-shift-right selects from the caret to the end.
+    visual.simulate_keystrokes("cmd-shift-right");
+    visual.simulate_keystrokes("backspace");
+    assert_eq!(value(&cx, &state), "x");
+
+    // cmd-up / cmd-down mirror the jumps.
+    visual.simulate_keystrokes("cmd-down");
+    visual.simulate_keystrokes("x");
+    assert_eq!(value(&cx, &state), "xx");
+    visual.simulate_keystrokes("cmd-up");
+    visual.simulate_keystrokes("y");
+    assert_eq!(value(&cx, &state), "yxx");
+}
+
+#[cfg(target_os = "macos")]
+#[test]
+fn cmd_backspace_deletes_to_the_field_start() {
+    let (cx, state, mut visual) = input_window("hello", false);
+    focus(&mut visual, &state);
+    // The caret starts at the end; cmd-backspace clears the whole field.
+    visual.simulate_keystrokes("cmd-backspace");
+    assert_eq!(value(&cx, &state), "");
+}
+
+#[test]
+fn undo_reverts_a_typing_burst_as_one_step() {
+    let (cx, state, mut visual) = input_window("", false);
+    focus(&mut visual, &state);
+
+    visual.simulate_keystrokes("h e l l o");
+    visual.simulate_keystrokes("cmd-z");
+    assert_eq!(value(&cx, &state), "");
+    visual.simulate_keystrokes("cmd-shift-z");
+    assert_eq!(value(&cx, &state), "hello");
+}
+
+#[test]
+fn undo_steps_through_edits_outside_the_group_interval() {
+    let (cx, state, mut visual) = input_window("", false);
+    focus(&mut visual, &state);
+    visual.update(|_, cx| {
+        state.update(cx, |state, _| state.set_group_interval(Duration::ZERO));
+    });
+
+    visual.simulate_keystrokes("a b");
+    assert_eq!(value(&cx, &state), "ab");
+    visual.simulate_keystrokes("cmd-z");
+    assert_eq!(value(&cx, &state), "a");
+    visual.simulate_keystrokes("cmd-z");
+    assert_eq!(value(&cx, &state), "");
+    visual.simulate_keystrokes("cmd-shift-z");
+    assert_eq!(value(&cx, &state), "a");
+    visual.simulate_keystrokes("cmd-shift-z");
+    assert_eq!(value(&cx, &state), "ab");
+
+    // A deletion gets its own entry and undoes back to the typed text.
+    visual.simulate_keystrokes("backspace");
+    assert_eq!(value(&cx, &state), "a");
+    visual.simulate_keystrokes("cmd-z");
+    assert_eq!(value(&cx, &state), "ab");
+}
+
+#[test]
+fn new_edits_clear_the_redo_stack() {
+    let (cx, state, mut visual) = input_window("", false);
+    focus(&mut visual, &state);
+
+    visual.simulate_keystrokes("a");
+    visual.simulate_keystrokes("cmd-z");
+    visual.simulate_keystrokes("b");
+    visual.simulate_keystrokes("cmd-shift-z");
+    assert_eq!(value(&cx, &state), "b");
+    visual.simulate_keystrokes("cmd-z");
+    assert_eq!(value(&cx, &state), "");
+}
+
+#[test]
+fn set_value_clears_the_history() {
+    let (cx, state, mut visual) = input_window("", false);
+    focus(&mut visual, &state);
+
+    visual.simulate_keystrokes("typed");
+    visual.update(|window, cx| {
+        state.update(cx, |state, cx| state.set_value("preset", window, cx));
+    });
+    visual.simulate_keystrokes("cmd-z");
+    assert_eq!(value(&cx, &state), "preset");
+}
+
 #[test]
 fn shift_arrow_selects_and_backspace_removes_the_selection() {
     let (cx, state, mut visual) = input_window("ab", false);