anchor.diff:                  alignment: Alignment.bottomCenter,
                   child: BottomAppBar(
                     padding: customPadding,
  -                    child:ColoredBox(
  -                      color:Colors.green,
  -                      child:SizedBox(width: 300, height: 60),
  -                    ),
  +                  child: ColoredBox(
  +                    color: Colors.green,
  +                    child: SizedBox(width: 300, height: 60),
  +                  ),
                   ),
                 ),
               );
  
positive.code: 
      final BottomAppBar bottomAppBar = tester.widget(find.byType(BottomAppBar));
      expect(bottomAppBar.padding, customPadding);
      final  Rect babRect = tester.getRect(find.byType(BottomAppBar));
      final  Rect childRect = tester.getRect(find.byType(ColoredBox));
      expect(childRect, const Rect.fromLTRB(250, 530, 550, 590));
      expect(babRect, const Rect.fromLTRB(240, 520, 560, 600));
    });
  
negative.code:                 alignment: Alignment.bottomCenter,
                  child: BottomAppBar(
                    padding: customPadding,
                    child: ColoredBox(
                      color: Colors.green,
                      child: SizedBox(width: 300, height: 60),
                    ),
                  ),
                ),
              );
  