anchor.diff:      // Pointer signals should not cause overscroll.
       await tester.sendEventToBinding(testPointer.scroll(const Offset(0.0, -30.0)), result);
       expect(getScrollOffset(tester), 0.0);
  +  });
  +
  +  testWidgets('Scroll pointer signals are handled when there is competion', (WidgetTester tester) async {
  +    // This is a regression test. When there are multiple scrollables listening
  +    // to the same event, for example when scrollables are nested, there used
  +    // to be exceptions at scrolling events.
  +
  +    await pumpDoubleScrollableTest(tester, TargetPlatform.fuchsia);
  +    final Offset scrollEventLocation = tester.getCenter(find.byType(Viewport).last);
  +    final TestPointer testPointer = TestPointer(1, ui.PointerDeviceKind.mouse);
  +    // Create a hover event so that |testPointer| has a location when generating the scroll.
  +    testPointer.hover(scrollEventLocation);
  +    final HitTestResult result = tester.hitTestOnBinding(scrollEventLocation);
  +    await tester.sendEventToBinding(testPointer.scroll(const Offset(0.0, 20.0)), result);
  +    expect(getScrollOffset(tester, last: true), 20.0);
  +    // Pointer signals should not cause overscroll.
  +    await tester.sendEventToBinding(testPointer.scroll(const Offset(0.0, -30.0)), result);
  +    expect(getScrollOffset(tester, last: true), 0.0);
     });
   
     testWidgets('Scroll pointer signals are ignored when scrolling is disabled', (WidgetTester tester) async {
  
positive.code:   await tester.pump(const Duration(seconds: 5)); // to let the theme animate
  }
  
  const double dragOffset = 200.0;
  
  final LogicalKeyboardKey modifierKey = defaultTargetPlatform == TargetPlatform.macOS
      ? LogicalKeyboardKey.metaLeft
      : LogicalKeyboardKey.controlLeft;
  
  double getScrollOffset(WidgetTester tester) {
    final RenderViewport viewport = tester.renderObject(find.byType(Viewport));
    return viewport.offset.pixels;
  }
  
  
negative.code:   bool scrollable = true,
    bool reverse = false,
    ScrollController controller,
    Widget Function(Widget) wrapper,
  }) async {
    await tester.pumpWidget(MaterialApp(
      theme: ThemeData(
  