anchor.diff:    });
   
     testWidgets('BottomNavigationBar.fixed semantics', (WidgetTester tester) async {
  -    final SemanticsTester semantics = SemanticsTester(tester);
  -
       await tester.pumpWidget(
         boilerplate(
           textDirection: TextDirection.ltr,
  
positive.code:       ),
      );
  
      final TestSemantics expected = TestSemantics.root(
        children: <TestSemantics>[
          TestSemantics(
            children: <TestSemantics>[
              TestSemantics(
                children: <TestSemantics>[
                  TestSemantics(
                    flags: <SemanticsFlag>[
                      SemanticsFlag.isFocusable,
                      SemanticsFlag.isSelected,
                    ],
                    actions: <SemanticsAction>[SemanticsAction.tap],
                    label: 'Red\nTab 1 of 2',
                    textDirection: TextDirection.ltr,
                  ),
                  TestSemantics(
                    flags: <SemanticsFlag>[SemanticsFlag.isFocusable],
                    actions: <SemanticsAction>[SemanticsAction.tap],
                    label: 'Green\nTab 2 of 2',
                    textDirection: TextDirection.ltr,
                  ),
                ],
              ),
            ],
          ),
        ],
      );
      expect(semantics, hasSemantics(expected, ignoreId: true, ignoreTransform: true, ignoreRect: true));
  
      semantics.dispose();
    });
  
    testWidgets('BottomNavigationBar.shifting [showSelectedLabels]=false and [showUnselectedLabels]=false semantics', (WidgetTester tester) async {
      final SemanticsTester semantics = SemanticsTester(tester);
  
      await tester.pumpWidget(
        boilerplate(
          textDirection: TextDirection.ltr,
  
negative.code:     });
  
    testWidgets('BottomNavigationBar.fixed [showSelectedLabels]=false and [showUnselectedLabels]=false semantics', (WidgetTester tester) async {
      await tester.pumpWidget(
        boilerplate(
          textDirection: TextDirection.ltr,
  