[cupertino_ui] Remove two items assert to allow CupertinoTabBar to have one tab

packages/cupertino_ui/lib/src/bottom_tab_bar.dart

@@ -81,7 +81,7 @@ class CupertinoTabBar extends StatelessWidget implements PreferredSizeWidget {
         width: 0.0, // 0.0 means one physical pixel
       ),
     ),
-  }) : assert(items.length >= 2, "Tabs need at least 2 items to conform to Apple's HIG"),
+  }) : assert(items.length > 0, 'CupertinoTabBar requires at least one tab.'),
        assert(0 <= currentIndex && currentIndex < items.length),
        assert(height >= 0.0);
 

packages/cupertino_ui/pending_changelogs/change_2026_08_22_cupertino_tab_bar_single_item.yaml

@@ -0,0 +1,3 @@
+changelog: |
+  - Allows `CupertinoTabBar` to contain a single item.
+version: patch

packages/cupertino_ui/test/bottom_tab_bar_test.dart

@@ -22,26 +22,32 @@ Future<void> pumpWidgetWithBoilerplate(WidgetTester tester, Widget widget) async
 }
 
 Future<void> main() async {
-  testWidgets('Need at least 2 tabs', (WidgetTester tester) async {
-    await expectLater(
-      () => pumpWidgetWithBoilerplate(
-        tester,
-        CupertinoTabBar(
-          items: const <BottomNavigationBarItem>[
-            BottomNavigationBarItem(icon: Icon(CupertinoIcons.search), label: 'Tab 1'),
-          ],
-        ),
-      ),
+  test('CupertinoTabBar requires at least one item', () {
+    expect(
+      () => CupertinoTabBar(items: const <BottomNavigationBarItem>[]),
       throwsA(
         isAssertionError.having(
           (AssertionError error) => error.toString(),
           '.toString()',
-          contains('items.length'),
+          contains('CupertinoTabBar requires at least one tab.'),
         ),
       ),
     );
   });
 
+  testWidgets('CupertinoTabBar supports one item', (WidgetTester tester) async {
+    await pumpWidgetWithBoilerplate(
+      tester,
+      CupertinoTabBar(
+        items: const <BottomNavigationBarItem>[
+          BottomNavigationBarItem(icon: Icon(CupertinoIcons.search), label: 'Tab 1'),
+        ],
+      ),
+    );
+
+    expect(find.byType(CupertinoTabBar), findsOneWidget);
+  });
+
   testWidgets('Active and inactive colors', (WidgetTester tester) async {
     await pumpWidgetWithBoilerplate(
       tester,