anchor.diff:            child: new CustomScrollView(
               slivers: <Widget>[
                 new CupertinoRefreshControl(
  -                builder: mockHelper.builder,
  +                builder: builder,
                 ),
                 buildAListOfStuff(),
               ],
  
positive.code:         ),
        );
  
        // The function is referenced once while passing into CupertinoRefreshControl
        // but never called.
        verify(mockHelper.builder);
        verifyNoMoreInteractions(mockHelper);
  
        expect(
  
negative.code:           child: new CustomScrollView(
              slivers: <Widget>[
                new CupertinoRefreshControl(
                  builder: builder,
                  onRefresh: onRefresh,
                ),
                buildAListOfStuff(),
              ],
  