test(voice): cover chat history Down and draft restore

Up was covered through the chat panel; Down, restoring the unsent draft,
the native-key cases and resetting recall after an edit or a send were not.

scripts/format-scope.json

@@ -1119,6 +1119,7 @@
   "src/voice/panel/manualPanel.test.mjs",
   "src/voice/voiceMiniPreview.js",
   "src/voice/voiceMiniPreview.test.mjs",
+  "src/voice/chatPreferences.test.mjs",
   "src/voice/panel/nativeActivity.test.mjs",
   "src/voice/panel/inactivity.test.mjs",
   "src/voice/panel/actionObserver.test.mjs",

src/voice/chatPreferences.test.mjs

@@ -0,0 +1,101 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { bindChatPreferences } from './chatPreferences.js';
+import { createTestVoiceUi } from '../testSupport/voiceUi.mjs';
+
+// A draft field with a caret, as the chat input exposes it to the owner.
+function chatInput(t) {
+  const field = { value: '', selectionStart: 0, selectionEnd: 0 };
+  const prefs = bindChatPreferences({
+    ui: createTestVoiceUi(),
+    getDraft: () => field.value,
+    setDraft: (text, { caret = text.length } = {}) => {
+      field.value = text;
+      field.selectionStart = field.selectionEnd = caret;
+    },
+  });
+  t.after(() => prefs.destroy());
+  const press = (key, init = {}) => {
+    const event = {
+      key,
+      target: field,
+      defaultPrevented: false,
+      preventDefault() {
+        this.defaultPrevented = true;
+      },
+      ...init,
+    };
+    return { used: prefs.keydown(event), event };
+  };
+  const type = (text, caret = text.length) => {
+    field.value = text;
+    field.selectionStart = field.selectionEnd = caret;
+  };
+  return { field, prefs, press, type };
+}
+
+test('Up and Down step through sent messages and restore the unsent draft', (t) => {
+  const { field, prefs, press, type } = chatInput(t);
+  for (const text of ['Fly to Tokyo', 'Show live flights', 'Show earthquakes'])
+    prefs.remember(text);
+  type('Reset', 0);
+  for (const expected of [
+    'Show earthquakes',
+    'Show live flights',
+    'Fly to Tokyo',
+    'Fly to Tokyo',
+  ]) {
+    const { used, event } = press('ArrowUp');
+    assert.equal(used, true);
+    assert.equal(event.defaultPrevented, true);
+    assert.equal(field.value, expected);
+    assert.equal(field.selectionStart, 0);
+  }
+  for (const expected of ['Show live flights', 'Show earthquakes']) {
+    assert.equal(press('ArrowDown').used, true);
+    assert.equal(field.value, expected);
+  }
+  // Past the newest message, Down puts back what was being typed.
+  assert.equal(press('ArrowDown').used, true);
+  assert.equal(field.value, 'Reset');
+  assert.equal(field.selectionStart, 'Reset'.length);
+  // With no recalled message, Down stays native.
+  type('Reset', 0);
+  assert.equal(press('ArrowDown').used, false);
+});
+
+test('arrow keys stay native away from the start, with modifiers or a selection', (t) => {
+  const { field, prefs, press, type } = chatInput(t);
+  assert.equal(press('ArrowUp').used, false, 'nothing sent yet');
+  prefs.remember('Fly to Tokyo');
+  type('Show', 2);
+  assert.equal(press('ArrowUp').used, false, 'caret inside the text');
+  type('Show', 0);
+  for (const init of [
+    { shiftKey: true },
+    { altKey: true },
+    { ctrlKey: true },
+    { metaKey: true },
+    { isComposing: true },
+  ])
+    assert.equal(press('ArrowUp', init).used, false, JSON.stringify(init));
+  field.selectionEnd = 2;
+  assert.equal(press('ArrowUp').used, false, 'text selected');
+  assert.equal(field.value, 'Show');
+});
+
+test('editing a recalled message ends recall, and sending resets it', (t) => {
+  const { field, prefs, press, type } = chatInput(t);
+  prefs.remember('Fly to Tokyo');
+  prefs.remember('Show live flights');
+  press('ArrowUp');
+  assert.equal(field.value, 'Show live flights');
+  // An edit makes the text a new draft; Down no longer recalls.
+  type('Show live flights now', 0);
+  prefs.render();
+  assert.equal(press('ArrowDown').used, false);
+  prefs.remember('Show live flights now');
+  type('', 0);
+  press('ArrowUp');
+  assert.equal(field.value, 'Show live flights now');
+});