anchor.diff:    });
   
     testWidgets('confirmDismiss returns values: true, false, null', (WidgetTester tester) async {
  -    scrollDirection = Axis.vertical;
  -    dismissDirection = DismissDirection.horizontal;
       late DismissDirection confirmDismissDirection;
   
       Widget buildFrame(bool? confirmDismissValue) {
         return buildTest(
  -        confirmDismiss: (BuildContext context, DismissDirection dismissDirection) {
  +          scrollDirection: Axis.vertical,
  +          dismissDirection: DismissDirection.horizontal,
  +          confirmDismiss: (BuildContext context, DismissDirection dismissDirection) {
             confirmDismissDirection = dismissDirection;
             return Future<bool?>.value(confirmDismissValue);
           },
  
positive.code:     expect(controller.offset, 0.0);
      await dismissItem(tester, 0, gestureDirection: AxisDirection.up);
      expect(controller.offset, 99.9);
    });
  }
  
negative.code:   });
  
    testWidgets('DismissDirection.none does not prevent scrolling', (WidgetTester tester) async {
      final ScrollController controller = ScrollController();
  
      await tester.pumpWidget(
        buildTest(
          controller: controller,
          dismissDirection: DismissDirection.none,
        ),
      );
      expect(dismissedItems, isEmpty);
      expect(controller.offset, 0.0);
  
  