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// Copyright 2014 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

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// This file is separate from viewport_caching_test.dart because we can't use
// both testWidgets and rendering_tester in the same file - testWidgets will
// initialize a binding, which rendering_tester will attempt to re-initialize
// (or vice versa).

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@Tags(<String>['reduced-test-set'])
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library;
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import 'package:flutter/foundation.dart';
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import 'package:flutter/rendering.dart';
import 'package:flutter/widgets.dart';
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import 'package:flutter_test/flutter_test.dart';
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import 'package:leak_tracker_flutter_testing/leak_tracker_flutter_testing.dart';
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class _TestSliverPersistentHeaderDelegate extends SliverPersistentHeaderDelegate {
  _TestSliverPersistentHeaderDelegate({
    this.key,
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    required this.minExtent,
    required this.maxExtent,
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    this.vsync = const TestVSync(),
    this.showOnScreenConfiguration = const PersistentHeaderShowOnScreenConfiguration(),
  });

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  final Key? key;
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  @override
  final double maxExtent;

  @override
  final double minExtent;

  @override
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  final TickerProvider? vsync;
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  @override
  final PersistentHeaderShowOnScreenConfiguration showOnScreenConfiguration;

  @override
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  Widget build(BuildContext context, double shrinkOffset, bool overlapsContent) => SizedBox.expand(key: key);
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  @override
  bool shouldRebuild(_TestSliverPersistentHeaderDelegate oldDelegate) => true;
}

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void main() {
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  testWidgetsWithLeakTracking('Scrollable widget scrollDirection update test', (WidgetTester tester) async {
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    final ScrollController controller = ScrollController();
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    addTearDown(controller.dispose);
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    Widget buildFrame(Axis axis) {
      return Directionality(
        textDirection: TextDirection.ltr,
        child: Center(
          child: SizedBox(
            height: 100.0,
            width: 100.0,
            child: SingleChildScrollView(
              controller: controller,
              scrollDirection: axis,
              child: const SizedBox(
                width: 200,
                height: 200,
                child: SizedBox.shrink(),
              ),
            ),
          ),
        ),
      );
    }

    await tester.pumpWidget(buildFrame(Axis.vertical));
    expect(controller.position.pixels, 0.0);

    // Change the SingleChildScrollView.scrollDirection to horizontal.
    await tester.pumpWidget(buildFrame(Axis.horizontal));
    expect(controller.position.pixels, 0.0);

    final TestGesture gesture = await tester.startGesture(const Offset(400.0, 300.0));
    // Drag in the vertical direction should not cause scrolling.
    await gesture.moveBy(const Offset(0.0, 10.0));
    expect(controller.position.pixels, 0.0);
    await gesture.moveBy(const Offset(0.0, -10.0));
    expect(controller.position.pixels, 0.0);

    // Drag in the horizontal direction should cause scrolling.
    await gesture.moveBy(const Offset(-10.0, 0.0));
    expect(controller.position.pixels, 10.0);
    await gesture.moveBy(const Offset(10.0, 0.0));
    expect(controller.position.pixels, 0.0);
  });

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  testWidgetsWithLeakTracking('Viewport getOffsetToReveal - down', (WidgetTester tester) async {
    final ScrollController controller = ScrollController(initialScrollOffset: 300.0);
    addTearDown(controller.dispose);
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    List<Widget> children;
    await tester.pumpWidget(
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      Directionality(
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        textDirection: TextDirection.ltr,
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        child: Center(
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          child: SizedBox(
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            height: 200.0,
            width: 300.0,
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            child: ListView(
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              controller: controller,
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              children: children = List<Widget>.generate(20, (int i) {
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                return SizedBox(
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                  height: 100.0,
                  width: 300.0,
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                  child: Text('Tile $i'),
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                );
              }),
            ),
          ),
        ),
      ),
    );

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    final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;
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    final RenderObject target = tester.renderObject(find.byWidget(children[5], skipOffstage: false));
    RevealedOffset revealed = viewport.getOffsetToReveal(target, 0.0);
    expect(revealed.offset, 500.0);
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    expect(revealed.rect, const Rect.fromLTWH(0.0, 0.0, 300.0, 100.0));
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    revealed = viewport.getOffsetToReveal(target, 1.0);
    expect(revealed.offset, 400.0);
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    expect(revealed.rect, const Rect.fromLTWH(0.0, 100.0, 300.0, 100.0));
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    revealed = viewport.getOffsetToReveal(target, 0.0, rect: const Rect.fromLTWH(40.0, 40.0, 10.0, 10.0));
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    expect(revealed.offset, 540.0);
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    expect(revealed.rect, const Rect.fromLTWH(40.0, 0.0, 10.0, 10.0));
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    revealed = viewport.getOffsetToReveal(target, 1.0, rect: const Rect.fromLTWH(40.0, 40.0, 10.0, 10.0));
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    expect(revealed.offset, 350.0);
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    expect(revealed.rect, const Rect.fromLTWH(40.0, 190.0, 10.0, 10.0));
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  });

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  testWidgetsWithLeakTracking('Viewport getOffsetToReveal - right', (WidgetTester tester) async {
    final ScrollController controller = ScrollController(initialScrollOffset: 300.0);
    addTearDown(controller.dispose);
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    List<Widget> children;

    await tester.pumpWidget(
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      Directionality(
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        textDirection: TextDirection.ltr,
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        child: Center(
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          child: SizedBox(
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            height: 300.0,
            width: 200.0,
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            child: ListView(
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              scrollDirection: Axis.horizontal,
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              controller: controller,
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              children: children = List<Widget>.generate(20, (int i) {
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                return SizedBox(
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                  height: 300.0,
                  width: 100.0,
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                  child: Text('Tile $i'),
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                );
              }),
            ),
          ),
        ),
      ),
    );

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    final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;
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    final RenderObject target = tester.renderObject(find.byWidget(children[5], skipOffstage: false));
    RevealedOffset revealed = viewport.getOffsetToReveal(target, 0.0);
    expect(revealed.offset, 500.0);
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    expect(revealed.rect, const Rect.fromLTWH(0.0, 0.0, 100.0, 300.0));
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    revealed = viewport.getOffsetToReveal(target, 1.0);
    expect(revealed.offset, 400.0);
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    expect(revealed.rect, const Rect.fromLTWH(100.0, 0.0, 100.0, 300.0));
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    revealed = viewport.getOffsetToReveal(target, 0.0, rect: const Rect.fromLTWH(40.0, 40.0, 10.0, 10.0));
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    expect(revealed.offset, 540.0);
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    expect(revealed.rect, const Rect.fromLTWH(0.0, 40.0, 10.0, 10.0));
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    revealed = viewport.getOffsetToReveal(target, 1.0, rect: const Rect.fromLTWH(40.0, 40.0, 10.0, 10.0));
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    expect(revealed.offset, 350.0);
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    expect(revealed.rect, const Rect.fromLTWH(190.0, 40.0, 10.0, 10.0));
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  });

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  testWidgetsWithLeakTracking('Viewport getOffsetToReveal - up', (WidgetTester tester) async {
    final ScrollController controller = ScrollController(initialScrollOffset: 300.0);
    addTearDown(controller.dispose);
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    List<Widget> children;

    await tester.pumpWidget(
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      Directionality(
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        textDirection: TextDirection.ltr,
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        child: Center(
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          child: SizedBox(
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            height: 200.0,
            width: 300.0,
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            child: ListView(
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              controller: controller,
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              reverse: true,
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              children: children = List<Widget>.generate(20, (int i) {
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                return SizedBox(
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                  height: 100.0,
                  width: 300.0,
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                  child: Text('Tile $i'),
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                );
              }),
            ),
          ),
        ),
      ),
    );

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    final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;
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    final RenderObject target = tester.renderObject(find.byWidget(children[5], skipOffstage: false));
    RevealedOffset revealed = viewport.getOffsetToReveal(target, 0.0);
    expect(revealed.offset, 500.0);
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    expect(revealed.rect, const Rect.fromLTWH(0.0, 100.0, 300.0, 100.0));
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    revealed = viewport.getOffsetToReveal(target, 1.0);
    expect(revealed.offset, 400.0);
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    expect(revealed.rect, const Rect.fromLTWH(0.0, 0.0, 300.0, 100.0));
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    revealed = viewport.getOffsetToReveal(target, 0.0, rect: const Rect.fromLTWH(40.0, 40.0, 10.0, 10.0));
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    expect(revealed.offset, 550.0);
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    expect(revealed.rect, const Rect.fromLTWH(40.0, 190.0, 10.0, 10.0));
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    revealed = viewport.getOffsetToReveal(target, 1.0, rect: const Rect.fromLTWH(40.0, 40.0, 10.0, 10.0));
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    expect(revealed.offset, 360.0);
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    expect(revealed.rect, const Rect.fromLTWH(40.0, 0.0, 10.0, 10.0));
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  });

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  testWidgetsWithLeakTracking('Viewport getOffsetToReveal - left', (WidgetTester tester) async {
    final ScrollController controller = ScrollController(initialScrollOffset: 300.0);
    addTearDown(controller.dispose);
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    List<Widget> children;

    await tester.pumpWidget(
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      Directionality(
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        textDirection: TextDirection.ltr,
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        child: Center(
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          child: SizedBox(
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            height: 300.0,
            width: 200.0,
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            child: ListView(
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              scrollDirection: Axis.horizontal,
              reverse: true,
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              controller: controller,
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              children: children = List<Widget>.generate(20, (int i) {
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                return SizedBox(
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                  height: 300.0,
                  width: 100.0,
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                  child: Text('Tile $i'),
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                );
              }),
            ),
          ),
        ),
      ),
    );

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    final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;
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    final RenderObject target = tester.renderObject(find.byWidget(children[5], skipOffstage: false));
    RevealedOffset revealed = viewport.getOffsetToReveal(target, 0.0);
    expect(revealed.offset, 500.0);
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    expect(revealed.rect, const Rect.fromLTWH(100.0, 0.0, 100.0, 300.0));
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    revealed = viewport.getOffsetToReveal(target, 1.0);
    expect(revealed.offset, 400.0);
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    expect(revealed.rect, const Rect.fromLTWH(0.0, 0.0, 100.0, 300.0));
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    revealed = viewport.getOffsetToReveal(target, 0.0, rect: const Rect.fromLTWH(40.0, 40.0, 10.0, 10.0));
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    expect(revealed.offset, 550.0);
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    expect(revealed.rect, const Rect.fromLTWH(190.0, 40.0, 10.0, 10.0));
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    revealed = viewport.getOffsetToReveal(target, 1.0, rect: const Rect.fromLTWH(40.0, 40.0, 10.0, 10.0));
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    expect(revealed.offset, 360.0);
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    expect(revealed.rect, const Rect.fromLTWH(0.0, 40.0, 10.0, 10.0));
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  });
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  testWidgetsWithLeakTracking('Viewport getOffsetToReveal Sliver - down', (WidgetTester tester) async {
    final ScrollController controller = ScrollController(initialScrollOffset: 300.0);
    addTearDown(controller.dispose);
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    final List<Widget> children = <Widget>[];
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: Center(
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          child: SizedBox(
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            height: 200.0,
            width: 300.0,
            child: CustomScrollView(
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              controller: controller,
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              slivers: List<Widget>.generate(20, (int i) {
                final Widget sliver = SliverToBoxAdapter(
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                  child: SizedBox(
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                    height: 100.0,
                    child: Text('Tile $i'),
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                  ),
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                );
                children.add(sliver);
                return SliverPadding(
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                  padding: const EdgeInsets.only(top: 22.0, bottom: 23.0),
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                  sliver: sliver,
                );
              }),
            ),
          ),
        ),
      ),
    );

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    final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;
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    final RenderObject target = tester.renderObject(find.byWidget(children[5], skipOffstage: false));
    RevealedOffset revealed = viewport.getOffsetToReveal(target, 0.0);
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    expect(revealed.offset, 5 * (100 + 22 + 23) + 22);
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    revealed = viewport.getOffsetToReveal(target, 1.0);
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    expect(revealed.offset, 5 * (100 + 22 + 23) + 22 - 100);

    // With rect specified.
    revealed = viewport.getOffsetToReveal(target, 0.0, rect: const Rect.fromLTRB(1, 2, 3, 4));
    expect(revealed.offset, 5 * (100 + 22 + 23) + 22 + 2);
    revealed = viewport.getOffsetToReveal(target, 1.0, rect: const Rect.fromLTRB(1, 2, 3, 4));
    expect(revealed.offset, 5 * (100 + 22 + 23) + 22 - (200 - 4));
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  });

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  testWidgetsWithLeakTracking('Viewport getOffsetToReveal Sliver - right', (WidgetTester tester) async {
    final ScrollController controller = ScrollController(initialScrollOffset: 300.0);
    addTearDown(controller.dispose);
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    final List<Widget> children = <Widget>[];
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: Center(
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          child: SizedBox(
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            height: 300.0,
            width: 200.0,
            child: CustomScrollView(
              scrollDirection: Axis.horizontal,
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              controller: controller,
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              slivers: List<Widget>.generate(20, (int i) {
                final Widget sliver = SliverToBoxAdapter(
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                    child: SizedBox(
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                      width: 100.0,
                      child: Text('Tile $i'),
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                    ),
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                );
                children.add(sliver);
                return SliverPadding(
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                  padding: const EdgeInsets.only(left: 22.0, right: 23.0),
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                  sliver: sliver,
                );
              }),
            ),
          ),
        ),
      ),
    );

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    final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;
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    final RenderObject target = tester.renderObject(find.byWidget(children[5], skipOffstage: false));
    RevealedOffset revealed = viewport.getOffsetToReveal(target, 0.0);
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    expect(revealed.offset, 5 * (100 + 22 + 23) + 22);
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    revealed = viewport.getOffsetToReveal(target, 1.0);
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    expect(revealed.offset, 5 * (100 + 22 + 23) + 22 - 100);

    // With rect specified.
    revealed = viewport.getOffsetToReveal(target, 0.0, rect: const Rect.fromLTRB(1, 2, 3, 4));
    expect(revealed.offset, 5 * (100 + 22 + 23) + 22 + 1);
    revealed = viewport.getOffsetToReveal(target, 1.0, rect: const Rect.fromLTRB(1, 2, 3, 4));
    expect(revealed.offset, 5 * (100 + 22 + 23) + 22 - (200 - 3));
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  });

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  testWidgetsWithLeakTracking('Viewport getOffsetToReveal Sliver - up', (WidgetTester tester) async {
    final ScrollController controller = ScrollController(initialScrollOffset: 300.0);
    addTearDown(controller.dispose);
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    final List<Widget> children = <Widget>[];
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: Center(
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          child: SizedBox(
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            height: 200.0,
            width: 300.0,
            child: CustomScrollView(
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              controller: controller,
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              reverse: true,
              slivers: List<Widget>.generate(20, (int i) {
                final Widget sliver = SliverToBoxAdapter(
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                    child: SizedBox(
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                      height: 100.0,
                      child: Text('Tile $i'),
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                    ),
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                );
                children.add(sliver);
                return SliverPadding(
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                  padding: const EdgeInsets.only(top: 22.0, bottom: 23.0),
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                  sliver: sliver,
                );
              }),
            ),
          ),
        ),
      ),
    );

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    final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;
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    final RenderObject target = tester.renderObject(find.byWidget(children[5], skipOffstage: false));
    RevealedOffset revealed = viewport.getOffsetToReveal(target, 0.0);
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    // Does not include the bottom padding of children[5] thus + 23 instead of + 22.
    expect(revealed.offset, 5 * (100 + 22 + 23) + 23);
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    revealed = viewport.getOffsetToReveal(target, 1.0);
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    expect(revealed.offset, 5 * (100 + 22 + 23) + 23 - 100);

    // With rect specified.
    revealed = viewport.getOffsetToReveal(target, 0.0, rect: const Rect.fromLTRB(1, 2, 3, 4));
    expect(revealed.offset, 5 * (100 + 22 + 23) + 23 + (100 - 4));
    revealed = viewport.getOffsetToReveal(target, 1.0, rect: const Rect.fromLTRB(1, 2, 3, 4));
    expect(revealed.offset, - 200 + 6 * (100 + 22 + 23) - 22 - 2);
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  });

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  testWidgetsWithLeakTracking('Viewport getOffsetToReveal Sliver - up - reverse growth', (WidgetTester tester) async {
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    const Key centerKey = ValueKey<String>('center');
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    const EdgeInsets padding = EdgeInsets.only(top: 22.0, bottom: 23.0);
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    const Widget centerSliver = SliverPadding(
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      key: centerKey,
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      padding: padding,
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      sliver: SliverToBoxAdapter(
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        child: SizedBox(
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          height: 100.0,
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          child: Text('Tile center'),
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        ),
      ),
    );
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    const Widget lowerItem = SizedBox(
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      height: 100.0,
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      child: Text('Tile lower'),
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    );
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    const Widget lowerSliver = SliverPadding(
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      padding: padding,
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      sliver: SliverToBoxAdapter(
        child: lowerItem,
      ),
    );

    await tester.pumpWidget(
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      const Directionality(
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        textDirection: TextDirection.ltr,
        child: Center(
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          child: SizedBox(
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            height: 200.0,
            width: 300.0,
            child: CustomScrollView(
              center: centerKey,
              reverse: true,
              slivers: <Widget>[lowerSliver, centerSliver],
            ),
          ),
        ),
      ),
    );

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    final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;
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    final RenderObject target = tester.renderObject(find.byWidget(lowerItem, skipOffstage: false));
    RevealedOffset revealed = viewport.getOffsetToReveal(target, 0.0);
    expect(revealed.offset, - 100 - 22);

    revealed = viewport.getOffsetToReveal(target, 1.0);
    expect(revealed.offset, - 100 - 22 - 100);
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    // With rect specified.
    revealed = viewport.getOffsetToReveal(target, 0.0, rect: const Rect.fromLTRB(1, 2, 3, 4));
    expect(revealed.offset, - 22 - 4);
    revealed = viewport.getOffsetToReveal(target, 1.0, rect: const Rect.fromLTRB(1, 2, 3, 4));
    expect(revealed.offset, -200 - 22 - 2);
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  });

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  testWidgetsWithLeakTracking('Viewport getOffsetToReveal Sliver - left - reverse growth', (WidgetTester tester) async {
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    const Key centerKey = ValueKey<String>('center');
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    const EdgeInsets padding = EdgeInsets.only(left: 22.0, right: 23.0);
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    const Widget centerSliver = SliverPadding(
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      key: centerKey,
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      padding: padding,
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      sliver: SliverToBoxAdapter(
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        child: SizedBox(
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          width: 100.0,
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          child: Text('Tile center'),
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        ),
      ),
    );
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    const Widget lowerItem = SizedBox(
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      width: 100.0,
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      child: Text('Tile lower'),
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    );
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    const Widget lowerSliver = SliverPadding(
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      padding: padding,
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      sliver: SliverToBoxAdapter(
        child: lowerItem,
      ),
    );

    await tester.pumpWidget(
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      const Directionality(
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        textDirection: TextDirection.ltr,
        child: Center(
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          child: SizedBox(
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            height: 200.0,
            width: 300.0,
            child: CustomScrollView(
              scrollDirection: Axis.horizontal,
              center: centerKey,
              reverse: true,
              slivers: <Widget>[lowerSliver, centerSliver],
            ),
          ),
        ),
      ),
    );

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    final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;
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    final RenderObject target = tester.renderObject(find.byWidget(lowerItem, skipOffstage: false));
    RevealedOffset revealed = viewport.getOffsetToReveal(target, 0.0);
    expect(revealed.offset, -100 - 22);

    revealed = viewport.getOffsetToReveal(target, 1.0);
    expect(revealed.offset, - 100 - 22 - 200);
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    // With rect specified.
    revealed = viewport.getOffsetToReveal(target, 0.0, rect: const Rect.fromLTRB(1, 2, 3, 4));
    expect(revealed.offset, - 22 - 3);
    revealed = viewport.getOffsetToReveal(target, 1.0, rect: const Rect.fromLTRB(1, 2, 3, 4));
    expect(revealed.offset, - 300 - 22 - 1);
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  });

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  testWidgetsWithLeakTracking('Viewport getOffsetToReveal Sliver - left', (WidgetTester tester) async {
    final ScrollController controller = ScrollController(initialScrollOffset: 300.0);
    addTearDown(controller.dispose);
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    final List<Widget> children = <Widget>[];
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: Center(
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          child: SizedBox(
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            height: 300.0,
            width: 200.0,
            child: CustomScrollView(
              scrollDirection: Axis.horizontal,
              reverse: true,
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              controller: controller,
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              slivers: List<Widget>.generate(20, (int i) {
                final Widget sliver = SliverToBoxAdapter(
565
                    child: SizedBox(
566 567
                      width: 100.0,
                      child: Text('Tile $i'),
568
                    ),
569 570 571
                );
                children.add(sliver);
                return SliverPadding(
572
                  padding: const EdgeInsets.only(left: 22.0, right: 23.0),
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                  sliver: sliver,
                );
              }),
            ),
          ),
        ),
      ),
    );

582
    final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;
583 584 585

    final RenderObject target = tester.renderObject(find.byWidget(children[5], skipOffstage: false));
    RevealedOffset revealed = viewport.getOffsetToReveal(target, 0.0);
586
    expect(revealed.offset, 5 * (100 + 22 + 23) + 23);
587 588

    revealed = viewport.getOffsetToReveal(target, 1.0);
589 590 591 592 593 594 595
    expect(revealed.offset, 5 * (100 + 22 + 23) + 23 - 100);

    // With rect specified.
    revealed = viewport.getOffsetToReveal(target, 0.0, rect: const Rect.fromLTRB(1, 2, 3, 4));
    expect(revealed.offset, 6 * (100 + 22 + 23) - 22 - 3);
    revealed = viewport.getOffsetToReveal(target, 1.0, rect: const Rect.fromLTRB(1, 2, 3, 4));
    expect(revealed.offset, -200  + 6 * (100 + 22 + 23) - 22 - 1);
596 597
  });

598
  testWidgetsWithLeakTracking('Nested Viewports showOnScreen', (WidgetTester tester) async {
599
    final List<ScrollController> controllersX = List<ScrollController>.generate(10, (int i) => ScrollController(initialScrollOffset: 400.0));
600
    final ScrollController controllerY = ScrollController(initialScrollOffset: 400.0);
601 602 603 604 605 606 607 608 609

    addTearDown((){
      controllerY.dispose();
      for (final ScrollController controller in controllersX) {
        controller.dispose();
      }
    });


610 611
    final List<List<Widget>> children = List<List<Widget>>.generate(10, (int y) {
      return List<Widget>.generate(10, (int x) {
612
        return SizedBox(
613 614 615 616 617 618
          height: 100.0,
          width: 100.0,
          child: Text('$x,$y'),
        );
      });
    });
619

620
    /// Builds a grid:
621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638
    ///
    ///       <- x ->
    ///   0 1 2 3 4 5 6 7 8 9
    /// 0 c c c c c c c c c c
    /// 1 c c c c c c c c c c
    /// 2 c c c c c c c c c c
    /// 3 c c c c c c c c c c  y
    /// 4 c c c c v v c c c c
    /// 5 c c c c v v c c c c
    /// 6 c c c c c c c c c c
    /// 7 c c c c c c c c c c
    /// 8 c c c c c c c c c c
    /// 9 c c c c c c c c c c
    ///
    /// Each c is a 100x100 container, v are containers visible in initial
    /// viewport.

    await tester.pumpWidget(
639
      Directionality(
640
        textDirection: TextDirection.ltr,
641
        child: Center(
642
          child: SizedBox(
643 644
            height: 200.0,
            width: 200.0,
645
            child: ListView(
646
              controller: controllerY,
647
              children: List<Widget>.generate(10, (int y) {
648
                return SizedBox(
649
                  height: 100.0,
650
                  child: ListView(
651 652
                    scrollDirection: Axis.horizontal,
                    controller: controllersX[y],
653
                    children: children[y],
654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767
                  ),
                );
              }),
            ),
          ),
        ),
      ),
    );

    // Already in viewport
    tester.renderObject(find.byWidget(children[4][4], skipOffstage: false)).showOnScreen();
    await tester.pumpAndSettle();
    expect(controllersX[4].offset, 400.0);
    expect(controllerY.offset, 400.0);

    controllersX[4].jumpTo(400.0);
    controllerY.jumpTo(400.0);
    await tester.pumpAndSettle();

    // Above viewport
    tester.renderObject(find.byWidget(children[3][4], skipOffstage: false)).showOnScreen();
    await tester.pumpAndSettle();
    expect(controllersX[3].offset, 400.0);
    expect(controllerY.offset, 300.0);

    controllersX[3].jumpTo(400.0);
    controllerY.jumpTo(400.0);
    await tester.pumpAndSettle();

    // Below viewport
    tester.renderObject(find.byWidget(children[6][4], skipOffstage: false)).showOnScreen();
    await tester.pumpAndSettle();
    expect(controllersX[6].offset, 400.0);
    expect(controllerY.offset, 500.0);

    controllersX[6].jumpTo(400.0);
    controllerY.jumpTo(400.0);
    await tester.pumpAndSettle();

    // Left of viewport
    tester.renderObject(find.byWidget(children[4][3], skipOffstage: false)).showOnScreen();
    await tester.pumpAndSettle();
    expect(controllersX[4].offset, 300.0);
    expect(controllerY.offset, 400.0);

    controllersX[4].jumpTo(400.0);
    controllerY.jumpTo(400.0);
    await tester.pumpAndSettle();

    // Right of viewport
    tester.renderObject(find.byWidget(children[4][6], skipOffstage: false)).showOnScreen();
    await tester.pumpAndSettle();
    expect(controllersX[4].offset, 500.0);
    expect(controllerY.offset, 400.0);

    controllersX[4].jumpTo(400.0);
    controllerY.jumpTo(400.0);
    await tester.pumpAndSettle();

    // Above and left of viewport
    tester.renderObject(find.byWidget(children[3][3], skipOffstage: false)).showOnScreen();
    await tester.pumpAndSettle();
    expect(controllersX[3].offset, 300.0);
    expect(controllerY.offset, 300.0);

    controllersX[3].jumpTo(400.0);
    controllerY.jumpTo(400.0);
    await tester.pumpAndSettle();

    // Below and left of viewport
    tester.renderObject(find.byWidget(children[6][3], skipOffstage: false)).showOnScreen();
    await tester.pumpAndSettle();
    expect(controllersX[6].offset, 300.0);
    expect(controllerY.offset, 500.0);

    controllersX[6].jumpTo(400.0);
    controllerY.jumpTo(400.0);
    await tester.pumpAndSettle();

    // Above and right of viewport
    tester.renderObject(find.byWidget(children[3][6], skipOffstage: false)).showOnScreen();
    await tester.pumpAndSettle();
    expect(controllersX[3].offset, 500.0);
    expect(controllerY.offset, 300.0);

    controllersX[3].jumpTo(400.0);
    controllerY.jumpTo(400.0);
    await tester.pumpAndSettle();

    // Below and right of viewport
    tester.renderObject(find.byWidget(children[6][6], skipOffstage: false)).showOnScreen();
    await tester.pumpAndSettle();
    expect(controllersX[6].offset, 500.0);
    expect(controllerY.offset, 500.0);

    controllersX[6].jumpTo(400.0);
    controllerY.jumpTo(400.0);
    await tester.pumpAndSettle();

    // Below and right of viewport with animations
    tester.renderObject(find.byWidget(children[6][6], skipOffstage: false)).showOnScreen(duration: const Duration(seconds: 2));
    await tester.pump();
    await tester.pump(const Duration(seconds: 1));
    expect(tester.hasRunningAnimations, isTrue);
    expect(controllersX[6].offset, greaterThan(400.0));
    expect(controllersX[6].offset, lessThan(500.0));
    expect(controllerY.offset, greaterThan(400.0));
    expect(controllerY.offset, lessThan(500.0));
    await tester.pumpAndSettle();
    expect(controllersX[6].offset, 500.0);
    expect(controllerY.offset, 500.0);
  });

  group('Nested viewports (same orientation) showOnScreen', () {
768
    final List<Widget> children = List<Widget>.generate(10, (int i) {
769
      return SizedBox(
770 771 772 773 774
        height: 100.0,
        width: 300.0,
        child: Text('$i'),
      );
    });
775

776
    Future<void> buildNestedScroller({ required WidgetTester tester, required ScrollController inner, required ScrollController outer }) {
777
      return tester.pumpWidget(
778
        Directionality(
779
          textDirection: TextDirection.ltr,
780
          child: Center(
781
            child: SizedBox(
782 783
              height: 200.0,
              width: 300.0,
784
              child: ListView(
785 786
                controller: outer,
                children: <Widget>[
787
                  const SizedBox(
788 789
                    height: 200.0,
                  ),
790
                  SizedBox(
791 792
                    height: 200.0,
                    width: 300.0,
793
                    child: ListView(
794
                      controller: inner,
795
                      children: children,
796 797
                    ),
                  ),
798
                  const SizedBox(
799
                    height: 200.0,
800
                  ),
801 802 803 804 805 806 807 808
                ],
              ),
            ),
          ),
        ),
      );
    }

809
    testWidgetsWithLeakTracking('Reverse List showOnScreen', (WidgetTester tester) async {
810
      addTearDown(tester.view.reset);
811 812 813 814 815
      const double screenHeight = 400.0;
      const double screenWidth = 400.0;
      const double itemHeight = screenHeight / 10.0;
      const ValueKey<String> centerKey = ValueKey<String>('center');

816 817
      tester.view.devicePixelRatio = 1.0;
      tester.view.physicalSize = const Size(screenWidth, screenHeight);
818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874

      await tester.pumpWidget(Directionality(
        textDirection: TextDirection.ltr,
        child: CustomScrollView(
            center: centerKey,
            reverse: true,
            slivers: <Widget>[
              SliverList(
                delegate: SliverChildListDelegate(
                  List<Widget>.generate(
                    10,
                        (int index) => SizedBox(
                      height: itemHeight,
                      child: Text('Item ${-index - 1}'),
                    ),
                  ),
                ),
              ),
              SliverList(
                key: centerKey,
                delegate: SliverChildListDelegate(
                  List<Widget>.generate(
                    1,
                        (int index) => const SizedBox(
                      height: itemHeight,
                      child: Text('Item 0'),
                    ),
                  ),
                ),
              ),
              SliverList(
                delegate: SliverChildListDelegate(
                  List<Widget>.generate(
                    10,
                    (int index) => SizedBox(
                      height: itemHeight,
                      child: Text('Item ${index + 1}'),
                    ),
                  ),
                ),
              ),
            ],
          ),
        ),
      );

      expect(find.text('Item -1'), findsNothing);

      final RenderBox itemNeg1 =
        tester.renderObject(find.text('Item -1', skipOffstage: false));

      itemNeg1.showOnScreen(duration: const Duration(seconds: 1));
      await tester.pumpAndSettle();

      expect(find.text('Item -1'), findsOneWidget);
    });

875
    testWidgetsWithLeakTracking('in view in inner, but not in outer', (WidgetTester tester) async {
876 877
      final ScrollController inner = ScrollController();
      final ScrollController outer = ScrollController();
878 879 880
      addTearDown(inner.dispose);
      addTearDown(outer.dispose);

881 882 883 884 885 886 887 888 889 890 891 892 893 894
      await buildNestedScroller(
        tester: tester,
        inner: inner,
        outer: outer,
      );
      expect(outer.offset, 0.0);
      expect(inner.offset, 0.0);

      tester.renderObject(find.byWidget(children[0], skipOffstage: false)).showOnScreen();
      await tester.pumpAndSettle();
      expect(inner.offset, 0.0);
      expect(outer.offset, 100.0);
    });

895
    testWidgetsWithLeakTracking('not in view of neither inner nor outer', (WidgetTester tester) async {
896 897
      final ScrollController inner = ScrollController();
      final ScrollController outer = ScrollController();
898 899 900
      addTearDown(inner.dispose);
      addTearDown(outer.dispose);

901 902 903 904 905 906 907 908 909 910 911 912 913 914
      await buildNestedScroller(
        tester: tester,
        inner: inner,
        outer: outer,
      );
      expect(outer.offset, 0.0);
      expect(inner.offset, 0.0);

      tester.renderObject(find.byWidget(children[4], skipOffstage: false)).showOnScreen();
      await tester.pumpAndSettle();
      expect(inner.offset, 300.0);
      expect(outer.offset, 200.0);
    });

915
    testWidgetsWithLeakTracking('in view in inner and outer', (WidgetTester tester) async {
916 917
      final ScrollController inner = ScrollController(initialScrollOffset: 200.0);
      final ScrollController outer = ScrollController(initialScrollOffset: 200.0);
918 919 920
      addTearDown(inner.dispose);
      addTearDown(outer.dispose);

921 922 923 924 925 926 927 928 929 930 931 932 933 934
      await buildNestedScroller(
        tester: tester,
        inner: inner,
        outer: outer,
      );
      expect(outer.offset, 200.0);
      expect(inner.offset, 200.0);

      tester.renderObject(find.byWidget(children[2])).showOnScreen();
      await tester.pumpAndSettle();
      expect(outer.offset, 200.0);
      expect(inner.offset, 200.0);
    });

935
    testWidgetsWithLeakTracking('inner shown in outer, but item not visible', (WidgetTester tester) async {
936 937
      final ScrollController inner = ScrollController(initialScrollOffset: 200.0);
      final ScrollController outer = ScrollController(initialScrollOffset: 200.0);
938 939 940
      addTearDown(inner.dispose);
      addTearDown(outer.dispose);

941 942 943 944 945 946 947 948 949 950 951 952 953 954
      await buildNestedScroller(
        tester: tester,
        inner: inner,
        outer: outer,
      );
      expect(outer.offset, 200.0);
      expect(inner.offset, 200.0);

      tester.renderObject(find.byWidget(children[5], skipOffstage: false)).showOnScreen();
      await tester.pumpAndSettle();
      expect(outer.offset, 200.0);
      expect(inner.offset, 400.0);
    });

955
    testWidgetsWithLeakTracking('inner half shown in outer, item only visible in inner', (WidgetTester tester) async {
956 957
      final ScrollController inner = ScrollController();
      final ScrollController outer = ScrollController(initialScrollOffset: 100.0);
958 959 960
      addTearDown(inner.dispose);
      addTearDown(outer.dispose);

961 962 963 964 965 966 967 968 969 970 971 972 973 974 975
      await buildNestedScroller(
        tester: tester,
        inner: inner,
        outer: outer,
      );
      expect(outer.offset, 100.0);
      expect(inner.offset, 0.0);

      tester.renderObject(find.byWidget(children[1])).showOnScreen();
      await tester.pumpAndSettle();
      expect(outer.offset, 200.0);
      expect(inner.offset, 0.0);
    });
  });

976
  testWidgetsWithLeakTracking('Nested Viewports showOnScreen with allowImplicitScrolling=false for inner viewport', (WidgetTester tester) async {
977 978 979
    // Regression test for https://github.com/flutter/flutter/issues/20893.

    List<Widget> slivers;
980 981
    final ScrollController controllerX = ScrollController();
    final ScrollController controllerY = ScrollController();
982 983
    addTearDown(controllerX.dispose);
    addTearDown(controllerY.dispose);
984 985 986 987 988

    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: Center(
989
          child: SizedBox(
990 991 992 993 994
            height: 200.0,
            width: 200.0,
            child: ListView(
              controller: controllerY,
              children: <Widget>[
995
                const SizedBox(
996 997
                  height: 150.0,
                ),
998
                SizedBox(
999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013
                  height: 100.0,
                  child: ListView(
                    physics: const PageScrollPhysics(), // Turns off `allowImplicitScrolling`
                    scrollDirection: Axis.horizontal,
                    controller: controllerX,
                    children: slivers = <Widget>[
                      Container(
                        width: 150.0,
                      ),
                      Container(
                        width: 150.0,
                      ),
                    ],
                  ),
                ),
1014
                const SizedBox(
1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029
                  height: 150.0,
                ),
              ],
            ),
          ),
        ),
      ),
    );

    tester.renderObject(find.byWidget(slivers[1])).showOnScreen();
    await tester.pumpAndSettle();
    expect(controllerX.offset, 0.0);
    expect(controllerY.offset, 50.0);
  });

1030
  testWidgetsWithLeakTracking('Nested Viewports showOnScreen on Sliver with allowImplicitScrolling=false for inner viewport', (WidgetTester tester) async {
1031
    Widget sliver;
1032 1033
    final ScrollController controllerX = ScrollController();
    final ScrollController controllerY = ScrollController();
1034 1035
    addTearDown(controllerX.dispose);
    addTearDown(controllerY.dispose);
1036 1037 1038 1039 1040

    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: Center(
1041
          child: SizedBox(
1042 1043 1044 1045 1046
            height: 200.0,
            width: 200.0,
            child: ListView(
              controller: controllerY,
              children: <Widget>[
1047
                const SizedBox(
1048 1049
                  height: 150.0,
                ),
1050
                SizedBox(
1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075
                  height: 100.0,
                  child: CustomScrollView(
                    physics: const PageScrollPhysics(), // Turns off `allowImplicitScrolling`
                    scrollDirection: Axis.horizontal,
                    controller: controllerX,
                    slivers: <Widget>[
                      SliverPadding(
                        padding: const EdgeInsets.all(25.0),
                        sliver: SliverToBoxAdapter(
                          child: Container(
                            width: 100.0,
                          ),
                        ),
                      ),
                      SliverPadding(
                        padding: const EdgeInsets.all(25.0),
                        sliver: sliver = SliverToBoxAdapter(
                          child: Container(
                            width: 100.0,
                          ),
                        ),
                      ),
                    ],
                  ),
                ),
1076
                const SizedBox(
1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091
                  height: 150.0,
                ),
              ],
            ),
          ),
        ),
      ),
    );

    tester.renderObject(find.byWidget(sliver)).showOnScreen();
    await tester.pumpAndSettle();
    expect(controllerX.offset, 0.0);
    expect(controllerY.offset, 25.0);
  });

1092
  testWidgetsWithLeakTracking('Viewport showOnScreen with objects larger than viewport', (WidgetTester tester) async {
1093
    List<Widget> children;
1094 1095
    final ScrollController controller = ScrollController(initialScrollOffset: 300.0);
    addTearDown(controller.dispose);
1096 1097

    await tester.pumpWidget(
1098
      Directionality(
1099
        textDirection: TextDirection.ltr,
1100
        child: Center(
1101
          child: SizedBox(
1102
            height: 200.0,
1103
            child: ListView(
1104
              controller: controller,
1105
              children: children = List<Widget>.generate(20, (int i) {
1106
                return SizedBox(
1107
                  height: 300.0,
1108
                  child: Text('Tile $i'),
1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151
                );
              }),
            ),
          ),
        ),
      ),
    );

    expect(controller.offset, 300.0);

    // Already aligned with leading edge, nothing happens.
    tester.renderObject(find.byWidget(children[1], skipOffstage: false)).showOnScreen();
    await tester.pumpAndSettle();
    expect(controller.offset, 300.0);

    // Above leading edge aligns trailing edges
    tester.renderObject(find.byWidget(children[0], skipOffstage: false)).showOnScreen();
    await tester.pumpAndSettle();
    expect(controller.offset, 100.0);

    // Below trailing edge aligns leading edges
    tester.renderObject(find.byWidget(children[1], skipOffstage: false)).showOnScreen();
    await tester.pumpAndSettle();
    expect(controller.offset, 300.0);

    controller.jumpTo(250.0);
    await tester.pumpAndSettle();
    expect(controller.offset, 250.0);

    // Partly visible across leading edge aligns trailing edges
    tester.renderObject(find.byWidget(children[0], skipOffstage: false)).showOnScreen();
    await tester.pumpAndSettle();
    expect(controller.offset, 100.0);

    controller.jumpTo(150.0);
    await tester.pumpAndSettle();
    expect(controller.offset, 150.0);

    // Partly visible across trailing edge aligns leading edges
    tester.renderObject(find.byWidget(children[1], skipOffstage: false)).showOnScreen();
    await tester.pumpAndSettle();
    expect(controller.offset, 300.0);
  });
1152

1153
  testWidgetsWithLeakTracking(
1154 1155 1156
    'Viewport showOnScreen should not scroll if the rect is already visible, even if it does not scroll linearly',
    (WidgetTester tester) async {
      List<Widget> children;
1157 1158
      final ScrollController controller = ScrollController(initialScrollOffset: 300.0);
      addTearDown(controller.dispose);
1159 1160 1161 1162 1163 1164

      const Key headerKey = Key('header');
      await tester.pumpWidget(
        Directionality(
          textDirection: TextDirection.ltr,
          child: Center(
1165
            child: SizedBox(
1166 1167
              height: 600.0,
              child: CustomScrollView(
1168
                controller: controller,
1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179
                slivers: children = List<Widget>.generate(20, (int i) {
                  return i == 10
                  ? SliverPersistentHeader(
                    pinned: true,
                    delegate: _TestSliverPersistentHeaderDelegate(
                      minExtent: 100,
                      maxExtent: 300,
                      key: headerKey,
                    ),
                  )
                  : SliverToBoxAdapter(
1180
                    child: SizedBox(
1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210
                      height: 300.0,
                      child: Text('Tile $i'),
                    ),
                  );
                }),
              ),
            ),
          ),
        ),
      );

      controller.jumpTo(300.0 * 15);
      await tester.pumpAndSettle();

      final Finder pinnedHeaderContent = find.descendant(
        of: find.byWidget(children[10]),
        matching: find.byKey(headerKey),
      );

      // The persistent header is pinned to the leading edge thus still visible,
      // the viewport should not scroll.
      tester.renderObject(pinnedHeaderContent).showOnScreen();
      await tester.pumpAndSettle();
      expect(controller.offset, 300.0 * 15);

      // The 11th child will be partially obstructed by the persistent header,
      // the viewport should scroll to reveal it.
      controller.jumpTo(
        11 * 300.0  // Preceding headers
        + 200.0     // Shrinks the pinned header to minExtent
1211
        + 100.0,     // Obstructs the leading 100 pixels of the 11th header
1212 1213 1214 1215 1216 1217
      );
      await tester.pumpAndSettle();

      tester.renderObject(find.byWidget(children[11], skipOffstage: false)).showOnScreen();
      await tester.pumpAndSettle();
      expect(controller.offset, lessThan(11 * 300.0 + 200.0 + 100.0));
1218 1219
    },
  );
1220 1221

  void testFloatingHeaderShowOnScreen({ bool animated = true, Axis axis = Axis.vertical }) {
1222
    final TickerProvider? vsync = animated ? const TestVSync() : null;
1223
    const Key headerKey = Key('header');
1224 1225
    late List<Widget> children;
    final ScrollController controller = ScrollController(initialScrollOffset: 300.0);
1226

1227
    Widget buildList({ required SliverPersistentHeader floatingHeader, bool reversed = false }) {
1228 1229 1230
      return Directionality(
        textDirection: TextDirection.ltr,
        child: Center(
1231
          child: SizedBox(
1232 1233 1234 1235 1236
            height: 400.0,
            width: 400.0,
            child: CustomScrollView(
              scrollDirection: axis,
              center: reversed ? const Key('19') : null,
1237
              controller: controller,
1238 1239 1240 1241 1242
              slivers: children = List<Widget>.generate(20, (int i) {
                  return i == 10
                  ? floatingHeader
                  : SliverToBoxAdapter(
                    key: (i == 19) ? const Key('19') : null,
1243
                    child: SizedBox(
1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258
                      height: 300.0,
                      width: 300,
                      child: Text('Tile $i'),
                    ),
                  );
              }),
            ),
          ),
        ),
      );
    }

    double mainAxisExtent(WidgetTester tester, Finder finder) {
      final RenderObject renderObject = tester.renderObject(finder);
      if (renderObject is RenderSliver) {
1259
        return renderObject.geometry!.paintExtent;
1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271
      }

      final RenderBox renderBox = renderObject as RenderBox;
      switch (axis) {
        case Axis.horizontal:
          return renderBox.size.width;
        case Axis.vertical:
          return renderBox.size.height;
      }
    }

    group('animated: $animated, scrollDirection: $axis', () {
1272
      testWidgetsWithLeakTracking(
1273 1274 1275 1276 1277 1278 1279 1280 1281
        'RenderViewportBase.showOnScreen',
        (WidgetTester tester) async {
          await tester.pumpWidget(
            buildList(
              floatingHeader: SliverPersistentHeader(
                pinned: true,
                floating: true,
                delegate: _TestSliverPersistentHeaderDelegate(minExtent: 100, maxExtent: 300, key: headerKey, vsync: vsync),
              ),
1282
            ),
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          );

          final Finder pinnedHeaderContent = find.byKey(headerKey, skipOffstage: false);

          controller.jumpTo(300.0 * 15);
          await tester.pumpAndSettle();
          expect(mainAxisExtent(tester, pinnedHeaderContent), lessThan(300));

          // The persistent header is pinned to the leading edge thus still visible,
          // the viewport should not scroll.
          tester.renderObject(pinnedHeaderContent).showOnScreen(
            descendant: tester.renderObject(pinnedHeaderContent),
            rect: Offset.zero & const Size(300, 300),
          );
          await tester.pumpAndSettle();
          // The header expands but doesn't move.
          expect(controller.offset, 300.0 * 15);
          expect(mainAxisExtent(tester, pinnedHeaderContent), 300);

          // The rect specifies that the persistent header needs to be 1 pixel away
          // from the leading edge of the viewport. Ignore the 1 pixel, the viewport
          // should not scroll.
          //
          // See: https://github.com/flutter/flutter/issues/25507.
          tester.renderObject(pinnedHeaderContent).showOnScreen(
            descendant: tester.renderObject(pinnedHeaderContent),
            rect: const Offset(-1, -1) & const Size(300, 300),
          );
          await tester.pumpAndSettle();
          expect(controller.offset, 300.0 * 15);
          expect(mainAxisExtent(tester, pinnedHeaderContent), 300);
1314 1315
        },
      );
1316

1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356
      testWidgetsWithLeakTracking('RenderViewportBase.showOnScreen twice almost instantly', (WidgetTester tester) async{
        // Regression test for https://github.com/flutter/flutter/issues/137901
        await tester.pumpWidget(
          buildList(
            floatingHeader: SliverPersistentHeader(
              pinned: true,
              floating: true,
              delegate: _TestSliverPersistentHeaderDelegate(minExtent: 100, maxExtent: 300, key: headerKey, vsync: vsync),
            ),
          ),
        );

        final Finder pinnedHeaderContent = find.byKey(headerKey, skipOffstage: false);

        controller.jumpTo(300.0 * 15);
        await tester.pumpAndSettle();
        expect(mainAxisExtent(tester, pinnedHeaderContent), lessThan(300));


        tester.renderObject(pinnedHeaderContent).showOnScreen(
          descendant: tester.renderObject(pinnedHeaderContent),
          // Adding different rect to check if the second showOnScreen call
          // leads to a different result.
          // When the animation has forward status and the second showOnScreen
          // is called, the new animation won't start.
          rect: Offset.zero & const Size(150, 150),
          duration: const Duration(seconds: 3),
        );
        await tester.pump(const Duration(seconds: 1));

        tester.renderObject(pinnedHeaderContent).showOnScreen(
          descendant: tester.renderObject(pinnedHeaderContent),
          rect: Offset.zero & const Size(300, 300),
        );

        await tester.pumpAndSettle();
        expect(controller.offset, 300.0 * 15);
        expect(mainAxisExtent(tester, pinnedHeaderContent), 150);
      });

1357
      testWidgetsWithLeakTracking(
1358 1359 1360 1361 1362 1363 1364 1365
        'RenderViewportBase.showOnScreen but no child',
        (WidgetTester tester) async {
          await tester.pumpWidget(
            buildList(
              floatingHeader: SliverPersistentHeader(
                key: headerKey,
                pinned: true,
                floating: true,
1366
                delegate: _TestSliverPersistentHeaderDelegate(minExtent: 100, maxExtent: 300, vsync: vsync),
1367
              ),
1368
            ),
1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397
          );

          final Finder pinnedHeaderContent = find.byKey(headerKey, skipOffstage: false);

          controller.jumpTo(300.0 * 15);
          await tester.pumpAndSettle();
          expect(mainAxisExtent(tester, pinnedHeaderContent), lessThan(300));

          // The persistent header is pinned to the leading edge thus still visible,
          // the viewport should not scroll.
          tester.renderObject(pinnedHeaderContent).showOnScreen(
            rect: Offset.zero & const Size(300, 300),
          );
          await tester.pumpAndSettle();
          // The header expands but doesn't move.
          expect(controller.offset, 300.0 * 15);
          expect(mainAxisExtent(tester, pinnedHeaderContent), 300);

          // The rect specifies that the persistent header needs to be 1 pixel away
          // from the leading edge of the viewport. Ignore the 1 pixel, the viewport
          // should not scroll.
          //
          // See: https://github.com/flutter/flutter/issues/25507.
          tester.renderObject(pinnedHeaderContent).showOnScreen(
            rect: const Offset(-1, -1) & const Size(300, 300),
          );
          await tester.pumpAndSettle();
          expect(controller.offset, 300.0 * 15);
          expect(mainAxisExtent(tester, pinnedHeaderContent), 300);
1398 1399
        },
      );
1400

1401
      testWidgetsWithLeakTracking(
1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416
        'RenderViewportBase.showOnScreen with maxShowOnScreenExtent ',
        (WidgetTester tester) async {
          await tester.pumpWidget(
            buildList(
              floatingHeader: SliverPersistentHeader(
                pinned: true,
                floating: true,
                delegate: _TestSliverPersistentHeaderDelegate(
                  minExtent: 100,
                  maxExtent: 300,
                  key: headerKey,
                  vsync: vsync,
                  showOnScreenConfiguration: const PersistentHeaderShowOnScreenConfiguration(maxShowOnScreenExtent: 200),
                ),
              ),
1417
            ),
1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458
          );

          final Finder pinnedHeaderContent = find.byKey(headerKey, skipOffstage: false);

          controller.jumpTo(300.0 * 15);
          await tester.pumpAndSettle();
          // childExtent was initially 100.
          expect(mainAxisExtent(tester, pinnedHeaderContent), 100);

          tester.renderObject(pinnedHeaderContent).showOnScreen(
            descendant: tester.renderObject(pinnedHeaderContent),
            rect: Offset.zero & const Size(300, 300),
          );
          await tester.pumpAndSettle();
          // The header doesn't move. It would have expanded to 300 but
          // maxShowOnScreenExtent is 200, preventing it from doing so.
          expect(controller.offset, 300.0 * 15);
          expect(mainAxisExtent(tester, pinnedHeaderContent), 200);

          // ignoreLeading still works.
          tester.renderObject(pinnedHeaderContent).showOnScreen(
            descendant: tester.renderObject(pinnedHeaderContent),
            rect: const Offset(-1, -1) & const Size(300, 300),
          );
          await tester.pumpAndSettle();
          expect(controller.offset, 300.0 * 15);
          expect(mainAxisExtent(tester, pinnedHeaderContent), 200);

          // Move the viewport so that its childExtent reaches 250.
          controller.jumpTo(300.0 * 10 + 50.0);
          await tester.pumpAndSettle();
          expect(mainAxisExtent(tester, pinnedHeaderContent), 250);

          // Doesn't move, doesn't expand or shrink, leading still ignored.
          tester.renderObject(pinnedHeaderContent).showOnScreen(
            descendant: tester.renderObject(pinnedHeaderContent),
            rect: const Offset(-1, -1) & const Size(300, 300),
          );
          await tester.pumpAndSettle();
          expect(controller.offset, 300.0 * 10 + 50.0);
          expect(mainAxisExtent(tester, pinnedHeaderContent), 250);
1459 1460
        },
      );
1461

1462
      testWidgetsWithLeakTracking(
1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477
        'RenderViewportBase.showOnScreen with minShowOnScreenExtent ',
        (WidgetTester tester) async {
          await tester.pumpWidget(
            buildList(
              floatingHeader: SliverPersistentHeader(
                pinned: true,
                floating: true,
                delegate: _TestSliverPersistentHeaderDelegate(
                  minExtent: 100,
                  maxExtent: 300,
                  key: headerKey,
                  vsync: vsync,
                  showOnScreenConfiguration: const PersistentHeaderShowOnScreenConfiguration(minShowOnScreenExtent: 200),
                ),
              ),
1478
            ),
1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519
          );

          final Finder pinnedHeaderContent = find.byKey(headerKey, skipOffstage: false);

          controller.jumpTo(300.0 * 15);
          await tester.pumpAndSettle();
          // childExtent was initially 100.
          expect(mainAxisExtent(tester, pinnedHeaderContent), 100);

          tester.renderObject(pinnedHeaderContent).showOnScreen(
            descendant: tester.renderObject(pinnedHeaderContent),
            rect: Offset.zero & const Size(110, 110),
          );
          await tester.pumpAndSettle();
          // The header doesn't move. It would have expanded to 110 but
          // minShowOnScreenExtent is 200, preventing it from doing so.
          expect(controller.offset, 300.0 * 15);
          expect(mainAxisExtent(tester, pinnedHeaderContent), 200);

          // ignoreLeading still works.
          tester.renderObject(pinnedHeaderContent).showOnScreen(
            descendant: tester.renderObject(pinnedHeaderContent),
            rect: const Offset(-1, -1) & const Size(110, 110),
          );
          await tester.pumpAndSettle();
          expect(controller.offset, 300.0 * 15);
          expect(mainAxisExtent(tester, pinnedHeaderContent), 200);

          // Move the viewport so that its childExtent reaches 250.
          controller.jumpTo(300.0 * 10 + 50.0);
          await tester.pumpAndSettle();
          expect(mainAxisExtent(tester, pinnedHeaderContent), 250);

          // Doesn't move, doesn't expand or shrink, leading still ignored.
          tester.renderObject(pinnedHeaderContent).showOnScreen(
            descendant: tester.renderObject(pinnedHeaderContent),
            rect: const Offset(-1, -1) & const Size(110, 110),
          );
          await tester.pumpAndSettle();
          expect(controller.offset, 300.0 * 10 + 50.0);
          expect(mainAxisExtent(tester, pinnedHeaderContent), 250);
1520 1521
        },
      );
1522

1523
      testWidgetsWithLeakTracking(
1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534
        'RenderViewportBase.showOnScreen should not scroll if the rect is already visible, '
        'even if it does not scroll linearly (reversed order version)',
        (WidgetTester tester) async {
          await tester.pumpWidget(
            buildList(
              floatingHeader: SliverPersistentHeader(
                pinned: true,
                floating: true,
                delegate: _TestSliverPersistentHeaderDelegate(minExtent: 100, maxExtent: 300, key: headerKey, vsync: vsync),
              ),
              reversed: true,
1535
            ),
1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554
          );

          controller.jumpTo(-300.0 * 15);
          await tester.pumpAndSettle();

          final Finder pinnedHeaderContent = find.byKey(headerKey, skipOffstage: false);

          // The persistent header is pinned to the leading edge thus still visible,
          // the viewport should not scroll.
          tester.renderObject(pinnedHeaderContent).showOnScreen();
          await tester.pumpAndSettle();
          expect(controller.offset, -300.0 * 15);

          // children[9] will be partially obstructed by the persistent header,
          // the viewport should scroll to reveal it.
          controller.jumpTo(
            - 8 * 300.0 // Preceding headers 11 - 18, children[11]'s top edge is aligned to the leading edge.
            - 400.0     // Viewport height. children[10] (the pinned header) becomes pinned at the bottom of the screen.
            - 200.0     // Shrinks the pinned header to minExtent (100).
1555
            - 100.0,     // Obstructs the leading 100 pixels of the 11th header
1556 1557 1558 1559 1560 1561
          );
          await tester.pumpAndSettle();

          tester.renderObject(find.byWidget(children[9], skipOffstage: false)).showOnScreen();
          await tester.pumpAndSettle();
          expect(controller.offset, -8 * 300.0 - 400.0 - 200.0);
1562 1563
        },
      );
1564 1565 1566 1567
    });
  }

  group('Floating header showOnScreen', () {
1568 1569
    testFloatingHeaderShowOnScreen();
    testFloatingHeaderShowOnScreen(axis: Axis.horizontal);
1570 1571 1572 1573 1574
  });

  group('RenderViewport getOffsetToReveal renderBox to sliver coordinates conversion', () {
    const EdgeInsets padding = EdgeInsets.fromLTRB(22, 22, 34, 34);
    const Key centerKey = Key('5');
1575
    Widget buildList({ required Axis axis, bool reverse = false, bool reverseGrowth = false }) {
1576 1577 1578
      return Directionality(
        textDirection: TextDirection.ltr,
        child: Center(
1579
          child: SizedBox(
1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605
            height: 400.0,
            width: 400.0,
            child: CustomScrollView(
              scrollDirection: axis,
              reverse: reverse,
              center: reverseGrowth ? centerKey : null,
              slivers: List<Widget>.generate(6, (int i) {
                return SliverPadding(
                  key: i == 5 ? centerKey : null,
                  padding: padding,
                  sliver: SliverToBoxAdapter(
                    child: Container(
                      padding: padding,
                      height: 300.0,
                      width: 300.0,
                      child: Text('Tile $i'),
                    ),
                  ),
                );
              }),
            ),
          ),
        ),
      );
    }

1606
    testWidgetsWithLeakTracking('up, forward growth', (WidgetTester tester) async {
1607
      await tester.pumpWidget(buildList(axis: Axis.vertical, reverse: true));
1608 1609 1610 1611 1612 1613 1614
      final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;

      final RenderObject target = tester.renderObject(find.text('Tile 5', skipOffstage: false));
      final double revealOffset = viewport.getOffsetToReveal(target, 0.0).offset;
      expect(revealOffset, (300.0 + padding.horizontal)  * 5 + 34.0 * 2);
    });

1615
    testWidgetsWithLeakTracking('up, reverse growth', (WidgetTester tester) async {
1616 1617 1618 1619 1620 1621 1622 1623
      await tester.pumpWidget(buildList(axis: Axis.vertical, reverse: true, reverseGrowth: true));
      final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;

      final RenderObject target = tester.renderObject(find.text('Tile 0', skipOffstage: false));
      final double revealOffset = viewport.getOffsetToReveal(target, 0.0).offset;
      expect(revealOffset, -(300.0 + padding.horizontal)  * 5 + 34.0 * 2);
    });

1624
    testWidgetsWithLeakTracking('right, forward growth', (WidgetTester tester) async {
1625
      await tester.pumpWidget(buildList(axis: Axis.horizontal));
1626 1627 1628 1629 1630 1631 1632
      final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;

      final RenderObject target = tester.renderObject(find.text('Tile 5', skipOffstage: false));
      final double revealOffset = viewport.getOffsetToReveal(target, 0.0).offset;
      expect(revealOffset, (300.0 + padding.horizontal)  * 5 + 22.0 * 2);
    });

1633
    testWidgetsWithLeakTracking('right, reverse growth', (WidgetTester tester) async {
1634
      await tester.pumpWidget(buildList(axis: Axis.horizontal, reverseGrowth: true));
1635 1636 1637 1638 1639 1640 1641
      final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;

      final RenderObject target = tester.renderObject(find.text('Tile 0', skipOffstage: false));
      final double revealOffset = viewport.getOffsetToReveal(target, 0.0).offset;
      expect(revealOffset, -(300.0 + padding.horizontal)  * 5 + 22.0 * 2);
    });

1642
    testWidgetsWithLeakTracking('down, forward growth', (WidgetTester tester) async {
1643
      await tester.pumpWidget(buildList(axis: Axis.vertical));
1644 1645 1646 1647 1648 1649 1650
      final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;

      final RenderObject target = tester.renderObject(find.text('Tile 5', skipOffstage: false));
      final double revealOffset = viewport.getOffsetToReveal(target, 0.0).offset;
      expect(revealOffset, (300.0 + padding.horizontal)  * 5 + 22.0 * 2);
    });

1651
    testWidgetsWithLeakTracking('down, reverse growth', (WidgetTester tester) async {
1652
      await tester.pumpWidget(buildList(axis: Axis.vertical, reverseGrowth: true));
1653 1654 1655 1656 1657 1658 1659
      final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;

      final RenderObject target = tester.renderObject(find.text('Tile 0', skipOffstage: false));
      final double revealOffset = viewport.getOffsetToReveal(target, 0.0).offset;
      expect(revealOffset, -(300.0 + padding.horizontal)  * 5 + 22.0 * 2);
    });

1660
    testWidgetsWithLeakTracking('left, forward growth', (WidgetTester tester) async {
1661
      await tester.pumpWidget(buildList(axis: Axis.horizontal, reverse: true));
1662 1663 1664 1665 1666 1667 1668
      final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;

      final RenderObject target = tester.renderObject(find.text('Tile 5', skipOffstage: false));
      final double revealOffset = viewport.getOffsetToReveal(target, 0.0).offset;
      expect(revealOffset, (300.0 + padding.horizontal)  * 5 + 34.0 * 2);
    });

1669
    testWidgetsWithLeakTracking('left, reverse growth', (WidgetTester tester) async {
1670 1671 1672 1673 1674 1675 1676
      await tester.pumpWidget(buildList(axis: Axis.horizontal, reverse: true, reverseGrowth: true));
      final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;

      final RenderObject target = tester.renderObject(find.text('Tile 0', skipOffstage: false));
      final double revealOffset = viewport.getOffsetToReveal(target, 0.0).offset;
      expect(revealOffset, -(300.0 + padding.horizontal)  * 5 + 34.0 * 2);
    });
1677

1678
    testWidgetsWithLeakTracking('will not assert on mismatched axis', (WidgetTester tester) async {
1679 1680 1681 1682 1683 1684
      await tester.pumpWidget(buildList(axis: Axis.vertical, reverse: true, reverseGrowth: true));
      final RenderAbstractViewport viewport = tester.allRenderObjects.whereType<RenderAbstractViewport>().first;

      final RenderObject target = tester.renderObject(find.text('Tile 0', skipOffstage: false));
      viewport.getOffsetToReveal(target, 0.0, axis: Axis.horizontal);
    });
1685 1686
  });

1687
  testWidgetsWithLeakTracking('RenderViewportBase.showOnScreen reports the correct targetRect', (WidgetTester tester) async {
1688 1689
    final ScrollController innerController = ScrollController();
    final ScrollController outerController = ScrollController();
1690 1691
    addTearDown(innerController.dispose);
    addTearDown(outerController.dispose);
1692 1693 1694 1695 1696

    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: Center(
1697
          child: SizedBox(
1698 1699 1700 1701 1702 1703
            height: 300.0,
            child: CustomScrollView(
              cacheExtent: 0,
              controller: outerController,
              slivers: <Widget>[
                SliverToBoxAdapter(
1704
                  child: SizedBox(
1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731
                    height: 300,
                    child: CustomScrollView(
                      controller: innerController,
                      slivers: List<Widget>.generate(5, (int i) {
                        return SliverToBoxAdapter(
                          child: SizedBox(
                            height: 300.0,
                            child: Text('Tile $i'),
                          ),
                        );
                      }),
                    ),
                  ),
                ),
                const SliverToBoxAdapter(
                  child: SizedBox(
                    height: 300.0,
                    child: Text('hidden'),
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );

1732
    tester.renderObject(find.widgetWithText(SizedBox, 'Tile 1', skipOffstage: false).first).showOnScreen();
1733 1734 1735 1736 1737 1738
    await tester.pumpAndSettle();
    // The inner viewport scrolls to reveal the 2nd tile.
    expect(innerController.offset, 300.0);
    expect(outerController.offset, 0);
  });

1739 1740 1741 1742 1743
  group('unbounded constraints control test', () {
    Widget buildNestedWidget([Axis a1 = Axis.vertical, Axis a2 = Axis.horizontal]) {
      return Directionality(
        textDirection: TextDirection.ltr,
        child: Center(
1744 1745 1746 1747 1748 1749 1750
          child: ListView(
            scrollDirection: a1,
            children: List<Widget>.generate(10, (int y) {
              return ListView(
                scrollDirection: a2,
              );
            }),
1751 1752 1753 1754 1755 1756
          ),
        ),
      );
    }

    Future<void> expectFlutterError({
1757 1758 1759
      required Widget widget,
      required WidgetTester tester,
      required String message,
1760 1761
    }) async {
      final List<FlutterErrorDetails> errors = <FlutterErrorDetails>[];
1762
      final FlutterExceptionHandler? oldHandler = FlutterError.onError;
1763 1764 1765 1766 1767 1768 1769 1770
      FlutterError.onError = (FlutterErrorDetails error) => errors.add(error);
      try {
        await tester.pumpWidget(widget);
      } finally {
        FlutterError.onError = oldHandler;
      }
      expect(errors, isNotEmpty);
      expect(errors.first.exception, isFlutterError);
1771
      expect((errors.first.exception as FlutterError).toStringDeep(), message);
1772 1773
    }

1774
    testWidgetsWithLeakTracking('Horizontal viewport was given unbounded height', (WidgetTester tester) async {
1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787
      await expectFlutterError(
        widget: buildNestedWidget(),
        tester: tester,
        message:
          'FlutterError\n'
          '   Horizontal viewport was given unbounded height.\n'
          '   Viewports expand in the cross axis to fill their container and\n'
          '   constrain their children to match their extent in the cross axis.\n'
          '   In this case, a horizontal viewport was given an unlimited amount\n'
          '   of vertical space in which to expand.\n',
      );
    });

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    testWidgetsWithLeakTracking('Horizontal viewport was given unbounded width', (WidgetTester tester) async {
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      await expectFlutterError(
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        widget: buildNestedWidget(Axis.horizontal),
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        tester: tester,
        message:
          'FlutterError\n'
          '   Horizontal viewport was given unbounded width.\n'
          '   Viewports expand in the scrolling direction to fill their\n'
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          '   container. In this case, a horizontal viewport was given an\n'
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          '   unlimited amount of horizontal space in which to expand. This\n'
          '   situation typically happens when a scrollable widget is nested\n'
          '   inside another scrollable widget.\n'
          '   If this widget is always nested in a scrollable widget there is\n'
          '   no need to use a viewport because there will always be enough\n'
          '   horizontal space for the children. In this case, consider using a\n'
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          '   Row or Wrap instead. Otherwise, consider using a CustomScrollView\n'
          '   to concatenate arbitrary slivers into a single scrollable.\n',
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      );
    });

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    testWidgetsWithLeakTracking('Vertical viewport was given unbounded width', (WidgetTester tester) async {
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      await expectFlutterError(
        widget: buildNestedWidget(Axis.horizontal, Axis.vertical),
        tester: tester,
        message:
          'FlutterError\n'
          '   Vertical viewport was given unbounded width.\n'
          '   Viewports expand in the cross axis to fill their container and\n'
          '   constrain their children to match their extent in the cross axis.\n'
          '   In this case, a vertical viewport was given an unlimited amount\n'
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          '   of horizontal space in which to expand.\n',
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      );
    });

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    testWidgetsWithLeakTracking('Vertical viewport was given unbounded height', (WidgetTester tester) async {
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      await expectFlutterError(
        widget: buildNestedWidget(Axis.vertical, Axis.vertical),
        tester: tester,
        message:
          'FlutterError\n'
          '   Vertical viewport was given unbounded height.\n'
          '   Viewports expand in the scrolling direction to fill their\n'
          '   container. In this case, a vertical viewport was given an\n'
          '   unlimited amount of vertical space in which to expand. This\n'
          '   situation typically happens when a scrollable widget is nested\n'
          '   inside another scrollable widget.\n'
          '   If this widget is always nested in a scrollable widget there is\n'
          '   no need to use a viewport because there will always be enough\n'
          '   vertical space for the children. In this case, consider using a\n'
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          '   Column or Wrap instead. Otherwise, consider using a\n'
          '   CustomScrollView to concatenate arbitrary slivers into a single\n'
          '   scrollable.\n',
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      );
    });
  });

  test('Viewport debugThrowIfNotCheckingIntrinsics() control test', () {
    final RenderViewport renderViewport = RenderViewport(
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      crossAxisDirection: AxisDirection.right, offset: ViewportOffset.zero(),
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    );
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    late FlutterError error;
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    try {
      renderViewport.computeMinIntrinsicHeight(0);
    } on FlutterError catch (e) {
      error = e;
    }
    expect(
      error.toStringDeep(),
      'FlutterError\n'
      '   RenderViewport does not support returning intrinsic dimensions.\n'
      '   Calculating the intrinsic dimensions would require instantiating\n'
      '   every child of the viewport, which defeats the point of viewports\n'
      '   being lazy.\n'
      '   If you are merely trying to shrink-wrap the viewport in the main\n'
      '   axis direction, consider a RenderShrinkWrappingViewport render\n'
      '   object (ShrinkWrappingViewport widget), which achieves that\n'
      '   effect without implementing the intrinsic dimension API.\n',
    );

    final RenderShrinkWrappingViewport renderShrinkWrappingViewport = RenderShrinkWrappingViewport(
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      crossAxisDirection: AxisDirection.right, offset: ViewportOffset.zero(),
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    );
    try {
      renderShrinkWrappingViewport.computeMinIntrinsicHeight(0);
    } on FlutterError catch (e) {
      error = e;
    }
    expect(error, isNotNull);
    expect(
      error.toStringDeep(),
      'FlutterError\n'
      '   RenderShrinkWrappingViewport does not support returning intrinsic\n'
      '   dimensions.\n'
      '   Calculating the intrinsic dimensions would require instantiating\n'
      '   every child of the viewport, which defeats the point of viewports\n'
      '   being lazy.\n'
      '   If you are merely trying to shrink-wrap the viewport in the main\n'
      '   axis direction, you should be able to achieve that effect by just\n'
      '   giving the viewport loose constraints, without needing to measure\n'
      '   its intrinsic dimensions.\n',
    );
  });
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  group('Viewport childrenInPaintOrder control test', () {
    test('RenderViewport', () async {
      final List<RenderSliver> children = <RenderSliver>[
        RenderSliverToBoxAdapter(),
        RenderSliverToBoxAdapter(),
        RenderSliverToBoxAdapter(),
      ];

      final RenderViewport renderViewport = RenderViewport(
        crossAxisDirection: AxisDirection.right,
        offset: ViewportOffset.zero(),
        children: children,
      );

      // Children should be painted in reverse order to the list given
      expect(renderViewport.childrenInPaintOrder, equals(children.reversed));
      // childrenInPaintOrder should be reverse of childrenInHitTestOrder
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      expect(
        renderViewport.childrenInPaintOrder,
        equals(renderViewport.childrenInHitTestOrder.toList().reversed),
      );
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    });

    test('RenderShrinkWrappingViewport', () async {
      final List<RenderSliver> children = <RenderSliver>[
        RenderSliverToBoxAdapter(),
        RenderSliverToBoxAdapter(),
        RenderSliverToBoxAdapter(),
      ];

      final RenderShrinkWrappingViewport renderViewport =
          RenderShrinkWrappingViewport(
        crossAxisDirection: AxisDirection.right,
        offset: ViewportOffset.zero(),
        children: children,
      );

      // Children should be painted in reverse order to the list given
      expect(renderViewport.childrenInPaintOrder, equals(children.reversed));
      // childrenInPaintOrder should be reverse of childrenInHitTestOrder
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      expect(
        renderViewport.childrenInPaintOrder,
        equals(renderViewport.childrenInHitTestOrder.toList().reversed),
      );
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    });
  });

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  group('Overscrolling RenderShrinkWrappingViewport', () {
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    Widget buildSimpleShrinkWrap({
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      ScrollController? controller,
      Axis scrollDirection = Axis.vertical,
      ScrollPhysics? physics,
    }) {
      return Directionality(
        textDirection: TextDirection.ltr,
        child: MediaQuery(
          data: const MediaQueryData(),
          child: ListView.builder(
            controller: controller,
            physics: physics,
            scrollDirection: scrollDirection,
            shrinkWrap: true,
            itemBuilder: (BuildContext context, int index) => SizedBox(height: 50, width: 50, child: Text('Item $index')),
            itemCount: 20,
            itemExtent: 50,
          ),
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        ),
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      );
    }
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    Widget buildClippingShrinkWrap(
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      ScrollController controller, {
      bool constrain = false,
    }) {
      return Directionality(
        textDirection: TextDirection.ltr,
        child: MediaQuery(
          data: const MediaQueryData(),
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          child: ColoredBox(
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            color: const Color(0xFF000000),
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            child: Column(
              children: <Widget>[
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                // Translucent boxes above and below the shrinkwrapped viewport
                // make it easily discernible if the viewport is not being
                // clipped properly.
                Opacity(
                  opacity: 0.5,
                  child: Container(height: 100, color: const Color(0xFF00B0FF)),
                ),
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                Container(
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                  height: constrain ? 150 : null,
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                  color: const Color(0xFFF44336),
                  child: ListView.builder(
                    controller: controller,
                    shrinkWrap: true,
                    physics: const BouncingScrollPhysics(parent: AlwaysScrollableScrollPhysics()),
                    itemBuilder: (BuildContext context, int index) => Text('Item $index'),
                    itemCount: 10,
                  ),
                ),
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                Opacity(
                  opacity: 0.5,
                  child: Container(height: 100, color: const Color(0xFF00B0FF)),
                ),
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              ],
            ),
          ),
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        ),
      );
    }
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    testWidgetsWithLeakTracking('constrained viewport correctly clips overflow', (WidgetTester tester) async {
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      // Regression test for https://github.com/flutter/flutter/issues/89717
      final  ScrollController controller = ScrollController();
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      addTearDown(controller.dispose);

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      await tester.pumpWidget(
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        buildClippingShrinkWrap(controller, constrain: true)
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      );
      expect(controller.offset, 0.0);
      expect(tester.getTopLeft(find.text('Item 0')).dy, 100.0);
      expect(tester.getTopLeft(find.text('Item 9')).dy, 226.0);

      // Overscroll
      final TestGesture overscrollGesture = await tester.startGesture(tester.getCenter(find.text('Item 0')));
      await overscrollGesture.moveBy(const Offset(0, 100));
      await tester.pump();
      expect(controller.offset, -100.0);
      expect(tester.getTopLeft(find.text('Item 0')).dy, 200.0);
      await expectLater(
        find.byType(Directionality),
        matchesGoldenFile('shrinkwrap_clipped_constrained_overscroll.png'),
      );
      await overscrollGesture.up();
      await tester.pumpAndSettle();
      expect(controller.offset, 0.0);
      expect(tester.getTopLeft(find.text('Item 0')).dy, 100.0);
      expect(tester.getTopLeft(find.text('Item 9')).dy, 226.0);
    });
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    testWidgetsWithLeakTracking('correctly clips overflow without constraints', (WidgetTester tester) async {
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      // Regression test for https://github.com/flutter/flutter/issues/89717
      final  ScrollController controller = ScrollController();
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      addTearDown(controller.dispose);

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      await tester.pumpWidget(
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        buildClippingShrinkWrap(controller)
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      );
      expect(controller.offset, 0.0);
      expect(tester.getTopLeft(find.text('Item 0')).dy, 100.0);
      expect(tester.getTopLeft(find.text('Item 9')).dy, 226.0);

      // Overscroll
      final TestGesture overscrollGesture = await tester.startGesture(tester.getCenter(find.text('Item 0')));
      await overscrollGesture.moveBy(const Offset(0, 100));
      await tester.pump();
      expect(controller.offset, -100.0);
      expect(tester.getTopLeft(find.text('Item 0')).dy, 200.0);
      await expectLater(
        find.byType(Directionality),
        matchesGoldenFile('shrinkwrap_clipped_overscroll.png'),
      );
      await overscrollGesture.up();
      await tester.pumpAndSettle();
      expect(controller.offset, 0.0);
      expect(tester.getTopLeft(find.text('Item 0')).dy, 100.0);
      expect(tester.getTopLeft(find.text('Item 9')).dy, 226.0);
    });
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    testWidgetsWithLeakTracking('allows overscrolling on default platforms - vertical', (WidgetTester tester) async {
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      // Regression test for https://github.com/flutter/flutter/issues/10949
      // Scrollables should overscroll by default on iOS and macOS
      final  ScrollController controller = ScrollController();
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      addTearDown(controller.dispose);

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      await tester.pumpWidget(
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        buildSimpleShrinkWrap(controller: controller),
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      );
      expect(controller.offset, 0.0);
      expect(tester.getTopLeft(find.text('Item 0')).dy, 0.0);
      // Check overscroll at both ends
      // Start
      TestGesture overscrollGesture = await tester.startGesture(tester.getCenter(find.byType(ListView)));
      await overscrollGesture.moveBy(const Offset(0, 25));
      await tester.pump();
      expect(controller.offset, -25.0);
      expect(tester.getTopLeft(find.text('Item 0')).dy, 25.0);
      await overscrollGesture.up();
      await tester.pumpAndSettle();
      expect(controller.offset, 0.0);
      expect(tester.getTopLeft(find.text('Item 0')).dy, 0.0);
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      // End
      final double maxExtent = controller.position.maxScrollExtent;
      controller.jumpTo(controller.position.maxScrollExtent);
      await tester.pumpAndSettle();
      expect(controller.offset, maxExtent);
      expect(tester.getBottomLeft(find.text('Item 19')).dy, 600.0);

      overscrollGesture = await tester.startGesture(tester.getCenter(find.byType(ListView)));
      await overscrollGesture.moveBy(const Offset(0, -25));
      await tester.pump();
      expect(controller.offset, greaterThan(maxExtent));
      expect(tester.getBottomLeft(find.text('Item 19')).dy, 575.0);
      await overscrollGesture.up();
      await tester.pumpAndSettle();
      expect(controller.offset, maxExtent);
      expect(tester.getBottomLeft(find.text('Item 19')).dy, 600.0);
    }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS, TargetPlatform.macOS }));

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    testWidgetsWithLeakTracking('allows overscrolling on default platforms - horizontal', (WidgetTester tester) async {
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      // Regression test for https://github.com/flutter/flutter/issues/10949
      // Scrollables should overscroll by default on iOS and macOS
      final  ScrollController controller = ScrollController();
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      addTearDown(controller.dispose);

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      await tester.pumpWidget(
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        buildSimpleShrinkWrap(controller: controller, scrollDirection: Axis.horizontal),
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      );
      expect(controller.offset, 0.0);
      expect(tester.getTopLeft(find.text('Item 0')).dx, 0.0);
      // Check overscroll at both ends
      // Start
      TestGesture overscrollGesture = await tester.startGesture(tester.getCenter(find.byType(ListView)));
      await overscrollGesture.moveBy(const Offset(25, 0));
      await tester.pump();
      expect(controller.offset, -25.0);
      expect(tester.getTopLeft(find.text('Item 0')).dx, 25.0);
      await overscrollGesture.up();
      await tester.pumpAndSettle();
      expect(controller.offset, 0.0);
      expect(tester.getTopLeft(find.text('Item 0')).dx, 0.0);
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      // End
      final double maxExtent = controller.position.maxScrollExtent;
      controller.jumpTo(controller.position.maxScrollExtent);
      await tester.pumpAndSettle();
      expect(controller.offset, maxExtent);
      expect(tester.getTopRight(find.text('Item 19')).dx, 800.0);

      overscrollGesture = await tester.startGesture(tester.getCenter(find.byType(ListView)));
      await overscrollGesture.moveBy(const Offset(-25, 0));
      await tester.pump();
      expect(controller.offset, greaterThan(maxExtent));
      expect(tester.getTopRight(find.text('Item 19')).dx, 775.0);
      await overscrollGesture.up();
      await tester.pumpAndSettle();
      expect(controller.offset, maxExtent);
      expect(tester.getTopRight(find.text('Item 19')).dx, 800.0);
    }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS, TargetPlatform.macOS }));

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    testWidgetsWithLeakTracking('allows overscrolling per physics - vertical', (WidgetTester tester) async {
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      // Regression test for https://github.com/flutter/flutter/issues/10949
      // Scrollables should overscroll when the scroll physics allow
      final  ScrollController controller = ScrollController();
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      addTearDown(controller.dispose);

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      await tester.pumpWidget(
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        buildSimpleShrinkWrap(controller: controller, physics: const BouncingScrollPhysics()),
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      );
      expect(controller.offset, 0.0);
      expect(tester.getTopLeft(find.text('Item 0')).dy, 0.0);
      // Check overscroll at both ends
      // Start
      TestGesture overscrollGesture = await tester.startGesture(tester.getCenter(find.byType(ListView)));
      await overscrollGesture.moveBy(const Offset(0, 25));
      await tester.pump();
      expect(controller.offset, -25.0);
      expect(tester.getTopLeft(find.text('Item 0')).dy, 25.0);
      await overscrollGesture.up();
      await tester.pumpAndSettle();
      expect(controller.offset, 0.0);
      expect(tester.getTopLeft(find.text('Item 0')).dy, 0.0);
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      // End
      final double maxExtent = controller.position.maxScrollExtent;
      controller.jumpTo(controller.position.maxScrollExtent);
      await tester.pumpAndSettle();
      expect(controller.offset, maxExtent);
      expect(tester.getBottomLeft(find.text('Item 19')).dy, 600.0);

      overscrollGesture = await tester.startGesture(tester.getCenter(find.byType(ListView)));
      await overscrollGesture.moveBy(const Offset(0, -25));
      await tester.pump();
      expect(controller.offset, greaterThan(maxExtent));
      expect(tester.getBottomLeft(find.text('Item 19')).dy, 575.0);
      await overscrollGesture.up();
      await tester.pumpAndSettle();
      expect(controller.offset, maxExtent);
      expect(tester.getBottomLeft(find.text('Item 19')).dy, 600.0);
    });
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    testWidgetsWithLeakTracking('allows overscrolling per physics - horizontal', (WidgetTester tester) async {
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      // Regression test for https://github.com/flutter/flutter/issues/10949
      // Scrollables should overscroll when the scroll physics allow
      final  ScrollController controller = ScrollController();
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      addTearDown(controller.dispose);

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      await tester.pumpWidget(
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        buildSimpleShrinkWrap(
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          controller: controller,
          scrollDirection: Axis.horizontal,
          physics: const BouncingScrollPhysics(),
        ),
      );
      expect(controller.offset, 0.0);
      expect(tester.getTopLeft(find.text('Item 0')).dx, 0.0);
      // Check overscroll at both ends
      // Start
      TestGesture overscrollGesture = await tester.startGesture(tester.getCenter(find.byType(ListView)));
      await overscrollGesture.moveBy(const Offset(25, 0));
      await tester.pump();
      expect(controller.offset, -25.0);
      expect(tester.getTopLeft(find.text('Item 0')).dx, 25.0);
      await overscrollGesture.up();
      await tester.pumpAndSettle();
      expect(controller.offset, 0.0);
      expect(tester.getTopLeft(find.text('Item 0')).dx, 0.0);
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      // End
      final double maxExtent = controller.position.maxScrollExtent;
      controller.jumpTo(controller.position.maxScrollExtent);
      await tester.pumpAndSettle();
      expect(controller.offset, maxExtent);
      expect(tester.getTopRight(find.text('Item 19')).dx, 800.0);

      overscrollGesture = await tester.startGesture(tester.getCenter(find.byType(ListView)));
      await overscrollGesture.moveBy(const Offset(-25, 0));
      await tester.pump();
      expect(controller.offset, greaterThan(maxExtent));
      expect(tester.getTopRight(find.text('Item 19')).dx, 775.0);
      await overscrollGesture.up();
      await tester.pumpAndSettle();
      expect(controller.offset, maxExtent);
      expect(tester.getTopRight(find.text('Item 19')).dx, 800.0);
    });
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  });

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  testWidgetsWithLeakTracking('Handles infinite constraints when TargetPlatform is iOS or macOS', (WidgetTester tester) async {
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    // regression test for https://github.com/flutter/flutter/issues/45866
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
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        child: MediaQuery(
          data: const MediaQueryData(),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              GridView(
                shrinkWrap: true,
                gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
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                  crossAxisCount: 3,
                  childAspectRatio: 3,
                  mainAxisSpacing: 3,
                  crossAxisSpacing: 3,
                ),
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                children: const <Widget>[
                  Text('a'),
                  Text('b'),
                  Text('c'),
                ],
              ),
            ],
          ),
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        ),
      ),
    );

    expect(find.text('b'), findsOneWidget);
    await tester.drag(find.text('b'), const Offset(0, 200));
    await tester.pumpAndSettle();
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  }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS, TargetPlatform.macOS }));
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  testWidgetsWithLeakTracking('Viewport describeApproximateClip respects clipBehavior', (WidgetTester tester) async {
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    await tester.pumpWidget(const Directionality(
      textDirection: TextDirection.ltr,
      child: CustomScrollView(
        clipBehavior: Clip.none,
        slivers: <Widget>[
          SliverToBoxAdapter(child: SizedBox(width: 20, height: 20)),
        ]
      ),
    ));
    RenderViewport viewport = tester.allRenderObjects.whereType<RenderViewport>().first;
    expect(viewport.clipBehavior, Clip.none);
    bool visited = false;
    viewport.visitChildren((RenderObject child) {
      visited = true;
      expect(viewport.describeApproximatePaintClip(child as RenderSliver), null);
    });
    expect(visited, true);

    await tester.pumpWidget(const Directionality(
      textDirection: TextDirection.ltr,
      child: CustomScrollView(
        slivers: <Widget>[
          SliverToBoxAdapter(child: SizedBox(width: 20, height: 20)),
        ]
      ),
    ));
    viewport = tester.allRenderObjects.whereType<RenderViewport>().first;
    expect(viewport.clipBehavior, Clip.hardEdge);
    visited = false;
    viewport.visitChildren((RenderObject child) {
      visited = true;
      expect(viewport.describeApproximatePaintClip(child as RenderSliver), Offset.zero & viewport.size);
    });
    expect(visited, true);
  });
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  testWidgetsWithLeakTracking(
      'Shrinkwrapping viewport asserts bounded cross axis', (WidgetTester tester) async {
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    final List<FlutterErrorDetails> errors = <FlutterErrorDetails>[];
    FlutterError.onError = (FlutterErrorDetails error) => errors.add(error);
    // Vertical
    await tester.pumpWidget(Directionality(
        textDirection: TextDirection.ltr,
        child: ListView(
          scrollDirection: Axis.horizontal,
          children: <Widget>[
            ListView(
              shrinkWrap: true,
              children: const <Widget>[ SizedBox.square(dimension: 500) ],
            ),
          ],
        ),
      ));

    expect(errors, isNotEmpty);
    expect(errors.first.exception, isFlutterError);
    FlutterError error = errors.first.exception as FlutterError;
    expect(
      error.toString(),
      contains('Viewports expand in the cross axis to fill their container'),
    );
    errors.clear();

    // Horizontal
    await tester.pumpWidget(Directionality(
      textDirection: TextDirection.ltr,
      child: ListView(
        children: <Widget>[
          ListView(
            scrollDirection: Axis.horizontal,
            shrinkWrap: true,
            children: const <Widget>[ SizedBox.square(dimension: 500) ],
          ),
        ],
      ),
    ));

    expect(errors, isNotEmpty);
    expect(errors.first.exception, isFlutterError);
    error = errors.first.exception as FlutterError;
    expect(
      error.toString(),
      contains('Viewports expand in the cross axis to fill their container'),
    );
    errors.clear();

    // No children
    await tester.pumpWidget(Directionality(
      textDirection: TextDirection.ltr,
      child: ListView(
        scrollDirection: Axis.horizontal,
        children: <Widget>[
          ListView(
            shrinkWrap: true,
          ),
        ],
      ),
    ));

    expect(errors, isNotEmpty);
    expect(errors.first.exception, isFlutterError);
    error = errors.first.exception as FlutterError;
    expect(
      error.toString(),
      contains('Viewports expand in the cross axis to fill their container'),
    );
    errors.clear();
  });
2374
}