anchor.diff:      await tester.tap(find.text('Closed'));
       await tester.pump(const Duration(milliseconds: 200));
   
  -    final State stateOpening = tester.state(find.byType(Switch));
  +    final State stateOpening = tester.state(find.byType(DummyStatefulWidget));
       expect(stateOpening, isNotNull);
   
       await tester.pumpAndSettle();
       expect(find.text('Closed'), findsNothing);
  -    final State stateOpen = tester.state(find.byType(Switch));
  +    final State stateOpen = tester.state(find.byType(DummyStatefulWidget));
       expect(stateOpen, isNotNull);
       expect(stateOpen, same(stateOpening));
   
  
positive.code:     navigator.pop();
      await tester.pump(const Duration(milliseconds: 200));
      expect(find.text('Closed'), findsOneWidget);
      final State stateClosing = tester.state(find.byType(Switch));
      expect(stateClosing, isNotNull);
      expect(stateClosing, same(stateOpen));
    });
  
negative.code:             return const Text('Closed');
            },
            openBuilder: (BuildContext context, VoidCallback action) {
              return const DummyStatefulWidget();
            },
          ),
        ),
  