anchor.diff:    });
   
     testWidgets('Golden Test Placeholder Widget', (WidgetTester tester) async {
  +    // Different machines render this content differently. Since the golden
  +    // files are rendered on MacOS, this test should only be run on MacOS.
  +    // If the golden files are regenerated on another OS, please change this
  +    // test to only run on that OS.
  +    if (Platform.isMacOS)
  +      return;
  +
       final Map<int, Widget> children = <int, Widget>{};
       children[0] = new Container();
       children[1] = const Placeholder();
  
positive.code:   });
  
    testWidgets('Null input for value results in no child initially selected',
            (WidgetTester tester) async {
      final Map<int, Widget> children = <int, Widget>{};
      children[0] = const Text('Child 1');
      children[1] = const Text('Child 2');
  
negative.code:       ),
      );
  
      final RenderBox segmentedControl = tester
          .renderObject(find.byKey(const ValueKey<String>('Segmented Control')));
  
      // Subtract the 16.0px from each side. Remaining width should be allocated
      // to each child equally.
      final double childWidth = (segmentedControl.size.width - 32.0) / 3;
  
      final dynamic childList =
          getRenderSegmentedControl(tester).getChildrenAsList();
  
      for (dynamic child in childList) {
        expect(childWidth, child.parentData.surroundingRect.width);
      }
    });
  
    testWidgets('Width is finite in unbounded space',
        (WidgetTester tester) async {
      final Map<int, Widget> children = <int, Widget>{};
      children[0] = const Text('Child 1');
      children[1] = const Text('Child 2');
  