anchor.diff:                builder: (BuildContext context) {
                   ++buildCounter;
                   return new Container();
  -              }
  +              },
               );
  -          }
  -        }
  -      )
  +          },
  +        },
  +      ),
       );
   
       expect(buildCounter, 0);
  
positive.code:     await tester.pumpWidget(
        new MaterialApp(
          debugShowMaterialGrid: true,
          home: new StateMarker()
        )
      );
  
      final StateMarkerState state2 = tester.state(find.byType(StateMarker));
  
negative.code:     await tester.pumpWidget(
        new MaterialApp(
          home: new MaterialApp(
            home: new Text('Home sweet home'),
          ),
        ),
      );
  
      expect(find.text('Home sweet home'), findsOneWidget);
  