anchor.diff:      ];
   
       for (var item in log) {
  -      expect(tester.getTopLeft(find.text('$item')), equals
  -        (expectedTopLeftNormalizedOffsets[item] * cellLength));
  -      expect(tester.getSize(find.text('$item')), equals(_getTileSize
  -        (tiles[item],
  -          cellLength)));
  +      expect(tester.getTopLeft(find.text('$item')),
  +          equals(expectedTopLeftNormalizedOffsets[item] * cellLength));
  +      expect(tester.getSize(find.text('$item')),
  +          equals(_getTileSize(tiles[item], cellLength)));
       }
   
  -    expect(log, equals(<int>[
  -      0, 1, 2,
  -      3, 4, 5,
  -    ]));
  +    expect(
  +        log,
  +        equals(<int>[
  +          0,
  +          1,
  +          2,
  +          3,
  +          4,
  +          5,
  +        ]));
       log.clear();
   
  -    final ScrollableState scrollableState = tester.state(find.byType(Scrollable));
  +    final ScrollableState scrollableState =
  +        tester.state(find.byType(Scrollable));
       final ScrollPosition scrollPosition = scrollableState.position;
       scrollPosition.jumpTo(1000.0);
   
  
positive.code:     await tester.pump();
  
      for (var item in log) {
        expect(tester.getTopLeft(find.text('$item')), equals
          (expectedTopLeftNormalizedOffsets[item] * cellLength  - const Offset
          (0.0, 1000.0)));
        expect(tester.getSize(find.text('$item')), equals(_getTileSize
          (tiles[item],
            cellLength)));
      }
  
      expect(log, equals(<int>[
        6, 7, 8, 9,
        10, 11, 12, 13,
        14, 15, 16
      ]));
      log.clear();
  
    });
  }
  
negative.code:       );
      });
      final tiles = const <StaggeredTile>[
        const StaggeredTile.count(2, 2),
        const StaggeredTile.count(1, 1),
        const StaggeredTile.count(1, 2),
        const StaggeredTile.count(1, 1),
        const StaggeredTile.count(4, 1),
        const StaggeredTile.count(4, 2),
        const StaggeredTile.count(1, 1),
        const StaggeredTile.count(1, 1),
        const StaggeredTile.count(1, 1),
        const StaggeredTile.count(1, 1),
        const StaggeredTile.count(1, 4),
        const StaggeredTile.count(1, 3),
        const StaggeredTile.count(1, 2),
        const StaggeredTile.count(1, 1),
        const StaggeredTile.count(1, 1),
        const StaggeredTile.count(1, 1),
        const StaggeredTile.count(1, 1),
        const StaggeredTile.count(1, 1),
        const StaggeredTile.count(1, 1),
        const StaggeredTile.count(1, 1),
      ];
  
      await tester.pumpWidget(new Directionality(
        textDirection: TextDirection.ltr,
        child: new StaggeredGridView.count(
          crossAxisSpacing: 0.0,
          mainAxisSpacing: 0.0,
          crossAxisCount: crossAxisCount,
          staggeredTiles: tiles,
          children: widgets,
        ),
      ));
  
      List<Offset> expectedTopLeftNormalizedOffsets = const <Offset>[
        const Offset(0.0, 0.0),
        const Offset(2.0, 0.0),
        const Offset(3.0, 0.0),
        const Offset(2.0, 1.0),
        const Offset(0.0, 2.0),
        const Offset(0.0, 3.0),
        const Offset(0.0, 5.0),
        const Offset(1.0, 5.0),
        const Offset(2.0, 5.0),
        const Offset(3.0, 5.0),
        const Offset(0.0, 6.0),
        const Offset(1.0, 6.0),
        const Offset(2.0, 6.0),
        const Offset(3.0, 6.0),
        const Offset(3.0, 7.0),
        const Offset(2.0, 8.0),
        const Offset(3.0, 8.0),
  