anchor.diff:          child: new Column(
             children: <Widget>[
               new Test1215DismissableWidget('1'),
  -            new Test1215DismissableWidget('2')
  -          ]
  -        )
  -      )
  +            new Test1215DismissableWidget('2'),
  +          ],
  +        ),
  +      ),
       ));
       expect(find.text('1'), findsOneWidget);
       expect(find.text('2'), findsOneWidget);
  
positive.code: Widget buildTest({ double startToEndThreshold }) {
    Widget buildDismissableItem(int item) {
      return new Dismissable(
          key: new ValueKey<int>(item),
          direction: dismissDirection,
          onDismissed: (DismissDirection direction) {
            handleOnDismissed(direction, item);
          },
          onResize: () {
            handleOnResize(item);
          },
          background: background,
          dismissThresholds: startToEndThreshold == null
              ? <DismissDirection, double>{}
              : <DismissDirection, double>{DismissDirection.startToEnd: startToEndThreshold},
          child: new Container(
              width: itemExtent,
              height: itemExtent,
              child: new Text(item.toString())
          )
      );
    }
  
    return new Container(
        padding: const EdgeInsets.all(10.0),
        child: new ScrollableList(
            scrollDirection: scrollDirection,
            itemExtent: itemExtent,
            children: <int>[0, 1, 2, 3, 4]
                .where((int i) => !dismissedItems.contains(i))
                .map(buildDismissableItem)
        )
    );
  }
  
negative.code:       key: new ObjectKey(text),
        child: new AspectRatio(
          aspectRatio: 1.0,
          child: new Text(this.text),
        ),
      );
    }
  }
  