Timeline date headers

ts/test-both/state/selectors/items_test.ts

@@ -1,4 +1,4 @@
-// Copyright 2020-2021 Signal Messenger, LLC
+// Copyright 2020-2022 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
 
 import { assert } from 'chai';
@@ -8,6 +8,7 @@ import {
   getPinnedConversationIds,
   getPreferredLeftPaneWidth,
   getPreferredReactionEmoji,
+  getUsernamesEnabled,
 } from '../../../state/selectors/items';
 import type { StateType } from '../../../state/reducer';
 import type { ItemsStateType } from '../../../state/ducks/items';
@@ -143,4 +144,36 @@ describe('both/state/selectors/items', () => {
       assert.deepStrictEqual(actual, preferredReactionEmoji);
     });
   });
+
+  describe('#getUsernamesEnabled', () => {
+    it('returns false if the flag is missing or disabled', () => {
+      [
+        {},
+        { remoteConfig: {} },
+        {
+          remoteConfig: {
+            'desktop.usernames': {
+              name: 'desktop.usernames' as const,
+              enabled: false,
+            },
+          },
+        },
+      ].forEach(itemsState => {
+        const state = getRootState(itemsState);
+        assert.isFalse(getUsernamesEnabled(state));
+      });
+    });
+
+    it('returns true if the flag is enabled', () => {
+      const state = getRootState({
+        remoteConfig: {
+          'desktop.usernames': {
+            name: 'desktop.usernames' as const,
+            enabled: true,
+          },
+        },
+      });
+      assert.isTrue(getUsernamesEnabled(state));
+    });
+  });
 });