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

import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/services.dart';
import 'package:flutter_test/flutter_test.dart';

import '../rendering/mock_canvas.dart';
import '../widgets/semantics_tester.dart';

Widget buildSliverAppBarApp({
  bool floating = false,
  bool pinned = false,
  double? collapsedHeight,
  double? expandedHeight,
  bool snap = false,
  double toolbarHeight = kToolbarHeight,
}) {
  return MaterialApp(
    home: Scaffold(
      body: DefaultTabController(
        length: 3,
        child: CustomScrollView(
          primary: true,
          slivers: <Widget>[
            SliverAppBar(
              title: const Text('AppBar Title'),
              floating: floating,
              pinned: pinned,
              collapsedHeight: collapsedHeight,
              expandedHeight: expandedHeight,
              toolbarHeight: toolbarHeight,
              snap: snap,
              bottom: TabBar(
                tabs: <String>['A','B','C'].map<Widget>((String t) => Tab(text: 'TAB $t')).toList(),
              ),
            ),
            SliverToBoxAdapter(
              child: Container(
                height: 1200.0,
                color: Colors.orange[400],
              ),
            ),
          ],
        ),
      ),
    ),
  );
}

ScrollController primaryScrollController(WidgetTester tester) {
  return PrimaryScrollController.of(tester.element(find.byType(CustomScrollView)));
}

TextStyle? iconStyle(WidgetTester tester, IconData icon) {
  final RichText iconRichText = tester.widget<RichText>(
    find.descendant(of: find.byIcon(icon).first, matching: find.byType(RichText)),
  );
  return iconRichText.text.style;
}

double appBarHeight(WidgetTester tester) => tester.getSize(find.byType(AppBar, skipOffstage: false)).height;
double appBarTop(WidgetTester tester) => tester.getTopLeft(find.byType(AppBar, skipOffstage: false)).dy;
double appBarBottom(WidgetTester tester) => tester.getBottomLeft(find.byType(AppBar, skipOffstage: false)).dy;

double tabBarHeight(WidgetTester tester) => tester.getSize(find.byType(TabBar, skipOffstage: false)).height;

void main() {
  setUp(() {
    debugResetSemanticsIdCounter();
  });

  testWidgets('AppBar centers title on iOS', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        theme: ThemeData(platform: TargetPlatform.android),
        home: Scaffold(
          appBar: AppBar(
            title: const Text('X'),
          ),
        ),
      ),
    );

    final Finder title = find.text('X');
    Offset center = tester.getCenter(title);
    Size size = tester.getSize(title);
    expect(center.dx, lessThan(400 - size.width / 2.0));

    for (final TargetPlatform platform in <TargetPlatform>[TargetPlatform.iOS, TargetPlatform.macOS]) {
      // Clear the widget tree to avoid animating between platforms.
      await tester.pumpWidget(Container(key: UniqueKey()));

      await tester.pumpWidget(
        MaterialApp(
          theme: ThemeData(platform: platform),
          home: Scaffold(
            appBar: AppBar(
              title: const Text('X'),
            ),
          ),
        ),
      );

      center = tester.getCenter(title);
      size = tester.getSize(title);
      expect(center.dx, greaterThan(400 - size.width / 2.0), reason: 'on ${platform.name}');
      expect(center.dx, lessThan(400 + size.width / 2.0), reason: 'on ${platform.name}');

      // One action is still centered.

      await tester.pumpWidget(
        MaterialApp(
          theme: ThemeData(platform: platform),
          home: Scaffold(
            appBar: AppBar(
              title: const Text('X'),
              actions: const <Widget>[
                Icon(Icons.thumb_up),
              ],
            ),
          ),
        ),
      );

      center = tester.getCenter(title);
      size = tester.getSize(title);
      expect(center.dx, greaterThan(400 - size.width / 2.0), reason: 'on ${platform.name}');
      expect(center.dx, lessThan(400 + size.width / 2.0), reason: 'on ${platform.name}');

      // Two actions is left aligned again.

      await tester.pumpWidget(
        MaterialApp(
          theme: ThemeData(platform: platform),
          home: Scaffold(
            appBar: AppBar(
              title: const Text('X'),
              actions: const <Widget>[
                Icon(Icons.thumb_up),
                Icon(Icons.thumb_up),
              ],
            ),
          ),
        ),
      );

      center = tester.getCenter(title);
      size = tester.getSize(title);
      expect(center.dx, lessThan(400 - size.width / 2.0), reason: 'on ${platform.name}');
    }
  });

  testWidgets('AppBar centerTitle:true centers on Android', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        theme: ThemeData(platform: TargetPlatform.android),
        home: Scaffold(
          appBar: AppBar(
            centerTitle: true,
            title: const Text('X'),
          ),
        ),
      ),
    );

    final Finder title = find.text('X');
    final Offset center = tester.getCenter(title);
    final Size size = tester.getSize(title);
    expect(center.dx, greaterThan(400 - size.width / 2.0));
    expect(center.dx, lessThan(400 + size.width / 2.0));
  });

  testWidgets('AppBar centerTitle:false title start edge is 16.0 (LTR)', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        home: Scaffold(
          appBar: AppBar(
            centerTitle: false,
            title: const Placeholder(key: Key('X')),
          ),
        ),
      ),
    );

    final Finder titleWidget = find.byKey(const Key('X'));
    expect(tester.getTopLeft(titleWidget).dx, 16.0);
    expect(tester.getTopRight(titleWidget).dx, 800 - 16.0);
  });

  testWidgets('AppBar centerTitle:false title start edge is 16.0 (RTL)', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        home: Directionality(
          textDirection: TextDirection.rtl,
          child: Scaffold(
            appBar: AppBar(
              centerTitle: false,
              title: const Placeholder(key: Key('X')),
            ),
          ),
        ),
      ),
    );

    final Finder titleWidget = find.byKey(const Key('X'));
    expect(tester.getTopRight(titleWidget).dx, 800.0 - 16.0);
    expect(tester.getTopLeft(titleWidget).dx, 16.0);
  });

  testWidgets('AppBar titleSpacing:32 title start edge is 32.0 (LTR)', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        home: Scaffold(
          appBar: AppBar(
            centerTitle: false,
            titleSpacing: 32.0,
            title: const Placeholder(key: Key('X')),
          ),
        ),
      ),
    );

    final Finder titleWidget = find.byKey(const Key('X'));
    expect(tester.getTopLeft(titleWidget).dx, 32.0);
    expect(tester.getTopRight(titleWidget).dx, 800 - 32.0);
  });

  testWidgets('AppBar titleSpacing:32 title start edge is 32.0 (RTL)', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        home: Directionality(
          textDirection: TextDirection.rtl,
          child: Scaffold(
            appBar: AppBar(
              centerTitle: false,
              titleSpacing: 32.0,
              title: const Placeholder(key: Key('X')),
            ),
          ),
        ),
      ),
    );

    final Finder titleWidget = find.byKey(const Key('X'));
    expect(tester.getTopRight(titleWidget).dx, 800.0 - 32.0);
    expect(tester.getTopLeft(titleWidget).dx, 32.0);
  });

  testWidgets(
    'AppBar centerTitle:false leading button title left edge is 72.0 (LTR)',
    (WidgetTester tester) async {
      await tester.pumpWidget(
        MaterialApp(
          home: Scaffold(
            appBar: AppBar(
              centerTitle: false,
              title: const Text('X'),
            ),
            // A drawer causes a leading hamburger.
            drawer: const Drawer(),
          ),
        ),
      );

      expect(tester.getTopLeft(find.text('X')).dx, 72.0);
    },
  );

  testWidgets(
    'AppBar centerTitle:false leading button title left edge is 72.0 (RTL)',
    (WidgetTester tester) async {
      await tester.pumpWidget(
        MaterialApp(
          home: Directionality(
            textDirection: TextDirection.rtl,
            child: Scaffold(
              appBar: AppBar(
                centerTitle: false,
                title: const Text('X'),
              ),
              // A drawer causes a leading hamburger.
              drawer: const Drawer(),
            ),
          ),
        ),
      );

      expect(tester.getTopRight(find.text('X')).dx, 800.0 - 72.0);
    },
  );

  testWidgets('AppBar centerTitle:false title overflow OK', (WidgetTester tester) async {
    // The app bar's title should be constrained to fit within the available space
    // between the leading and actions widgets.

    final Key titleKey = UniqueKey();
    Widget leading = Container();
    List<Widget> actions = <Widget>[];

    Widget buildApp() {
      return MaterialApp(
        home: Scaffold(
          appBar: AppBar(
            leading: leading,
            centerTitle: false,
            title: Container(
              key: titleKey,
              constraints: BoxConstraints.loose(const Size(1000.0, 1000.0)),
            ),
            actions: actions,
          ),
        ),
      );
    }

    await tester.pumpWidget(buildApp());

    final Finder title = find.byKey(titleKey);
    expect(tester.getTopLeft(title).dx, 72.0);
    expect(
      tester.getSize(title).width,
      equals(
        800.0 // Screen width.
        - 56.0 // Leading button width.
        - 16.0 // Leading button to title padding.
        - 16.0, // Title right side padding.
      ),
    );

    actions = <Widget>[
      const SizedBox(width: 100.0),
      const SizedBox(width: 100.0),
    ];
    await tester.pumpWidget(buildApp());

    expect(tester.getTopLeft(title).dx, 72.0);
    // The title shrinks by 200.0 to allow for the actions widgets.
    expect(tester.getSize(title).width, equals(
      800.0 // Screen width.
      - 56.0 // Leading button width.
      - 16.0 // Leading button to title padding.
      - 16.0 // Title to actions padding
      - 200.0,
    )); // Actions' width.

    leading = Container(); // AppBar will constrain the width to 24.0
    await tester.pumpWidget(buildApp());
    expect(tester.getTopLeft(title).dx, 72.0);
    // Adding a leading widget shouldn't effect the title's size
    expect(tester.getSize(title).width, equals(800.0 - 56.0 - 16.0 - 16.0 - 200.0));
  });

  testWidgets('AppBar centerTitle:true title overflow OK (LTR)', (WidgetTester tester) async {
    // The app bar's title should be constrained to fit within the available space
    // between the leading and actions widgets. When it's also centered it may
    // also be start or end justified if it doesn't fit in the overall center.

    final Key titleKey = UniqueKey();
    double titleWidth = 700.0;
    Widget? leading = Container();
    List<Widget> actions = <Widget>[];

    Widget buildApp() {
      return MaterialApp(
        home: Scaffold(
          appBar: AppBar(
            leading: leading,
            centerTitle: true,
            title: Container(
              key: titleKey,
              constraints: BoxConstraints.loose(Size(titleWidth, 1000.0)),
            ),
            actions: actions,
          ),
        ),
      );
    }

    // Centering a title with width 700 within the 800 pixel wide test widget
    // would mean that its start edge would have to be 50. The material spec says
    // that the start edge of the title must be at least 72.
    await tester.pumpWidget(buildApp());

    final Finder title = find.byKey(titleKey);
    expect(tester.getTopLeft(title).dx, 72.0);
    expect(tester.getSize(title).width, equals(700.0));

    // Centering a title with width 620 within the 800 pixel wide test widget
    // would mean that its start edge would have to be 90. We reserve 72
    // on the start and the padded actions occupy 96 on the end. That
    // leaves 632, so the title is end justified but its width isn't changed.

    await tester.pumpWidget(buildApp());
    leading = null;
    titleWidth = 620.0;
    actions = <Widget>[
      const SizedBox(width: 48.0),
      const SizedBox(width: 48.0),
    ];
    await tester.pumpWidget(buildApp());
    expect(tester.getTopLeft(title).dx, 800 - 620 - 48 - 48 - 16);
    expect(tester.getSize(title).width, equals(620.0));
  });

  testWidgets('AppBar centerTitle:true title overflow OK (RTL)', (WidgetTester tester) async {
    // The app bar's title should be constrained to fit within the available space
    // between the leading and actions widgets. When it's also centered it may
    // also be start or end justified if it doesn't fit in the overall center.

    final Key titleKey = UniqueKey();
    double titleWidth = 700.0;
    Widget? leading = Container();
    List<Widget> actions = <Widget>[];

    Widget buildApp() {
      return MaterialApp(
        home: Directionality(
          textDirection: TextDirection.rtl,
          child: Scaffold(
            appBar: AppBar(
              leading: leading,
              centerTitle: true,
              title: Container(
                key: titleKey,
                constraints: BoxConstraints.loose(Size(titleWidth, 1000.0)),
              ),
              actions: actions,
            ),
          ),
        ),
      );
    }

    // Centering a title with width 700 within the 800 pixel wide test widget
    // would mean that its start edge would have to be 50. The material spec says
    // that the start edge of the title must be at least 72.
    await tester.pumpWidget(buildApp());

    final Finder title = find.byKey(titleKey);
    expect(tester.getTopRight(title).dx, 800.0 - 72.0);
    expect(tester.getSize(title).width, equals(700.0));

    // Centering a title with width 620 within the 800 pixel wide test widget
    // would mean that its start edge would have to be 90. We reserve 72
    // on the start and the padded actions occupy 96 on the end. That
    // leaves 632, so the title is end justified but its width isn't changed.

    await tester.pumpWidget(buildApp());
    leading = null;
    titleWidth = 620.0;
    actions = <Widget>[
      const SizedBox(width: 48.0),
      const SizedBox(width: 48.0),
    ];
    await tester.pumpWidget(buildApp());
    expect(tester.getTopRight(title).dx, 620 + 48 + 48 + 16);
    expect(tester.getSize(title).width, equals(620.0));
  });

  testWidgets('AppBar with no Scaffold', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        home: SizedBox(
          height: kToolbarHeight,
          child: AppBar(
            leading: const Text('L'),
            title: const Text('No Scaffold'),
            actions: const <Widget>[Text('A1'), Text('A2')],
          ),
        ),
      ),
    );

    expect(find.text('L'), findsOneWidget);
    expect(find.text('No Scaffold'), findsOneWidget);
    expect(find.text('A1'), findsOneWidget);
    expect(find.text('A2'), findsOneWidget);
  });

  testWidgets('AppBar render at zero size', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        home: Center(
          child: SizedBox.shrink(
            child: Scaffold(
              appBar: AppBar(
                title: const Text('X'),
              ),
            ),
          ),
        ),
      ),
    );

    final Finder title = find.text('X');
    expect(tester.getSize(title).isEmpty, isTrue);
  });

  testWidgets('AppBar actions are vertically centered', (WidgetTester tester) async {
    final UniqueKey appBarKey = UniqueKey();
    final UniqueKey leadingKey = UniqueKey();
    final UniqueKey titleKey = UniqueKey();
    final UniqueKey action0Key = UniqueKey();
    final UniqueKey action1Key = UniqueKey();

    await tester.pumpWidget(
      MaterialApp(
        home: Scaffold(
          appBar: AppBar(
            key: appBarKey,
            leading: SizedBox(key: leadingKey, height: 50.0),
            title: SizedBox(key: titleKey, height: 40.0),
            actions: <Widget>[
              SizedBox(key: action0Key, height: 20.0),
              SizedBox(key: action1Key, height: 30.0),
            ],
          ),
        ),
      ),
    );

    // The vertical center of the widget with key, in global coordinates.
    double yCenter(Key key) => tester.getCenter(find.byKey(key)).dy;

    expect(yCenter(appBarKey), equals(yCenter(leadingKey)));
    expect(yCenter(appBarKey), equals(yCenter(titleKey)));
    expect(yCenter(appBarKey), equals(yCenter(action0Key)));
    expect(yCenter(appBarKey), equals(yCenter(action1Key)));
  });

  testWidgets('AppBar drawer icon has default size', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        home: Scaffold(
          appBar: AppBar(
            title: const Text('Howdy!'),
          ),
          drawer: const Drawer(),
        ),
      ),
    );
    final double iconSize = const IconThemeData.fallback().size!;
    expect(
      tester.getSize(find.byIcon(Icons.menu)),
      equals(Size(iconSize, iconSize)),
    );
  });

  testWidgets('AppBar drawer icon has default color', (WidgetTester tester) async {
    final ThemeData themeData = ThemeData.from(colorScheme: const ColorScheme.light());
    final bool useMaterial3 = themeData.useMaterial3;

    await tester.pumpWidget(
      MaterialApp(
        theme: themeData,
        home: Scaffold(
          appBar: AppBar(
            title: const Text('Howdy!'),
          ),
          drawer: const Drawer(),
        ),
      ),
    );

    Color? iconColor() => iconStyle(tester, Icons.menu)?.color;
    final Color iconColorM2 = themeData.colorScheme.onPrimary;
    final Color iconColorM3 = themeData.colorScheme.onSurfaceVariant;
    expect(iconColor(), useMaterial3 ? iconColorM3 : iconColorM2);
  });

  testWidgets('AppBar drawer icon is sized by iconTheme', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        home: Scaffold(
          appBar: AppBar(
            title: const Text('Howdy!'),
            iconTheme: const IconThemeData(size: 30),
          ),
          drawer: const Drawer(),
        ),
      ),
    );
    expect(
      tester.getSize(find.byIcon(Icons.menu)),
      equals(const Size(30, 30)),
    );
  });

  testWidgets('AppBar drawer icon is colored by iconTheme', (WidgetTester tester) async {
    final ThemeData themeData = ThemeData.from(colorScheme: const ColorScheme.light());
    const Color color = Color(0xFF2196F3);

    await tester.pumpWidget(
      MaterialApp(
        theme: themeData,
        home: Scaffold(
          appBar: AppBar(
            title: const Text('Howdy!'),
            iconTheme: const IconThemeData(color: color),
          ),
          drawer: const Drawer(),
        ),
      ),
    );

    Color? iconColor() => iconStyle(tester, Icons.menu)?.color;

    expect(iconColor(), color);
  });

  testWidgets('AppBar endDrawer icon has default size', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        home: Scaffold(
          appBar: AppBar(
            title: const Text('Howdy!'),
          ),
          endDrawer: const Drawer(),
        ),
      ),
    );
    final double iconSize = const IconThemeData.fallback().size!;
    expect(
      tester.getSize(find.byIcon(Icons.menu)),
      equals(Size(iconSize, iconSize)),
    );
  });

  testWidgets('AppBar endDrawer icon has default color', (WidgetTester tester) async {
    final ThemeData themeData = ThemeData.from(colorScheme: const ColorScheme.light());
    final bool useMaterial3 = themeData.useMaterial3;

    await tester.pumpWidget(
      MaterialApp(
        theme: themeData,
        home: Scaffold(
          appBar: AppBar(
            title: const Text('Howdy!'),
          ),
          endDrawer: const Drawer(),
        ),
      ),
    );

    Color? iconColor() => iconStyle(tester, Icons.menu)?.color;
    final Color iconColorM2 = themeData.colorScheme.onPrimary;
    final Color iconColorM3 = themeData.colorScheme.onSurfaceVariant;
    expect(iconColor(), useMaterial3 ? iconColorM3 : iconColorM2);
  });

  testWidgets('AppBar endDrawer icon is sized by iconTheme', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        home: Scaffold(
          appBar: AppBar(
            title: const Text('Howdy!'),
            iconTheme: const IconThemeData(size: 30),
          ),
          endDrawer: const Drawer(),
        ),
      ),
    );
    expect(
      tester.getSize(find.byIcon(Icons.menu)),
      equals(const Size(30, 30)),
    );
  });

  testWidgets('AppBar endDrawer icon is colored by iconTheme', (WidgetTester tester) async {
    final ThemeData themeData = ThemeData.from(colorScheme: const ColorScheme.light());
    const Color color = Color(0xFF2196F3);

    await tester.pumpWidget(
      MaterialApp(
        theme: themeData,
        home: Scaffold(
          appBar: AppBar(
            title: const Text('Howdy!'),
            iconTheme: const IconThemeData(color: color),
          ),
          endDrawer: const Drawer(),
        ),
      ),
    );

    Color? iconColor() => iconStyle(tester, Icons.menu)?.color;

    expect(iconColor(), color);
  });

  testWidgets('leading widget extends to edge and is square', (WidgetTester tester) async {
    final ThemeData themeData = ThemeData(platform: TargetPlatform.android);
    final bool material3 = themeData.useMaterial3;
    await tester.pumpWidget(
      MaterialApp(
        theme: themeData,
        home: Scaffold(
          appBar: AppBar(
            title: const Text('X'),
          ),
          drawer: const Column(), // Doesn't really matter. Triggers a hamburger regardless.
        ),
      ),
    );

    // Default IconButton has a size of (48x48) in M3, (56x56) in M2
    final Finder hamburger = find.byType(IconButton);
    expect(tester.getTopLeft(hamburger), material3 ? const Offset(4.0, 4.0) : Offset.zero);
    expect(tester.getSize(hamburger), material3 ? const Size(48.0, 48.0) : const Size(56.0, 56.0));

    await tester.pumpWidget(
      MaterialApp(
        theme: themeData,
        home: Scaffold(
          appBar: AppBar(
            leading: Container(),
            title: const Text('X'),
          ),
        ),
      ),
    );

    // Default leading widget has a size of (56x56) for both M2 and M3
    final Finder leadingBox = find.byType(Container);
    expect(tester.getTopLeft(leadingBox), Offset.zero);
    expect(tester.getSize(leadingBox), const Size(56.0, 56.0));

    // The custom leading widget should still be 56x56 even if its size is smaller.
    await tester.pumpWidget(
      MaterialApp(
        theme: themeData,
        home: Scaffold(
          appBar: AppBar(
            leading: const SizedBox(height: 36, width: 36,),
            title: const Text('X'),
          ), // Doesn't really matter. Triggers a hamburger regardless.
        ),
      ),
    );

    final Finder leading = find.byType(SizedBox);
    expect(tester.getTopLeft(leading), Offset.zero);
    expect(tester.getSize(leading), const Size(56.0, 56.0));
  });

  testWidgets('test action is 4dp from edge and 48dp min', (WidgetTester tester) async {
    final ThemeData theme = ThemeData(platform: TargetPlatform.android);
    final bool material3 = theme.useMaterial3;
    await tester.pumpWidget(
      MaterialApp(
        theme: theme,
        home: Scaffold(
          appBar: AppBar(
            title: const Text('X'),
            actions: const <Widget> [
              IconButton(
                icon: Icon(Icons.share),
                onPressed: null,
                tooltip: 'Share',
                iconSize: 20.0,
              ),
              IconButton(
                icon: Icon(Icons.add),
                onPressed: null,
                tooltip: 'Add',
                iconSize: 60.0,
              ),
            ],
          ),
        ),
      ),
    );

    final Finder addButton = find.widgetWithIcon(IconButton, Icons.add);
    expect(tester.getTopRight(addButton), const Offset(800.0, 0.0));
    // It's still the size it was plus the 2 * 8dp padding from IconButton.
    expect(tester.getSize(addButton), const Size(60.0 + 2 * 8.0, 56.0));

    final Finder shareButton = find.widgetWithIcon(IconButton, Icons.share);
    // The 20dp icon is expanded to fill the IconButton's touch target to 48dp.
    expect(tester.getSize(shareButton), material3 ? const Size(48.0, 48.0) : const Size(48.0, 56.0));
  });

  testWidgets('SliverAppBar default configuration', (WidgetTester tester) async {
    await tester.pumpWidget(buildSliverAppBarApp());

    final ScrollController controller = primaryScrollController(tester);
    expect(controller.offset, 0.0);
    expect(find.byType(SliverAppBar), findsOneWidget);

    final double initialAppBarHeight = appBarHeight(tester);
    final double initialTabBarHeight = tabBarHeight(tester);

    // Scroll the not-pinned appbar partially out of view
    controller.jumpTo(50.0);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), initialAppBarHeight);
    expect(tabBarHeight(tester), initialTabBarHeight);

    // Scroll the not-pinned appbar out of view
    controller.jumpTo(600.0);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsNothing);
    expect(appBarHeight(tester), initialAppBarHeight);
    expect(tabBarHeight(tester), initialTabBarHeight);

    // Scroll the not-pinned appbar back into view
    controller.jumpTo(0.0);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), initialAppBarHeight);
    expect(tabBarHeight(tester), initialTabBarHeight);
  });

  testWidgets('SliverAppBar expandedHeight, pinned', (WidgetTester tester) async {

    await tester.pumpWidget(buildSliverAppBarApp(
      pinned: true,
      expandedHeight: 128.0,
    ));

    final ScrollController controller = primaryScrollController(tester);
    expect(controller.offset, 0.0);
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), 128.0);

    const double initialAppBarHeight = 128.0;
    final double initialTabBarHeight = tabBarHeight(tester);

    // Scroll the not-pinned appbar, collapsing the expanded height. At this
    // point both the toolbar and the tabbar are visible.
    controller.jumpTo(600.0);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(tabBarHeight(tester), initialTabBarHeight);
    expect(appBarHeight(tester), lessThan(initialAppBarHeight));
    expect(appBarHeight(tester), greaterThan(initialTabBarHeight));

    // Scroll the not-pinned appbar back into view
    controller.jumpTo(0.0);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), initialAppBarHeight);
    expect(tabBarHeight(tester), initialTabBarHeight);
  });

  testWidgets('SliverAppBar expandedHeight, pinned and floating', (WidgetTester tester) async {

    await tester.pumpWidget(buildSliverAppBarApp(
      floating: true,
      pinned: true,
      expandedHeight: 128.0,
    ));

    final ScrollController controller = primaryScrollController(tester);
    expect(controller.offset, 0.0);
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), 128.0);

    const double initialAppBarHeight = 128.0;
    final double initialTabBarHeight = tabBarHeight(tester);

    // Scroll the floating-pinned appbar, collapsing the expanded height. At this
    // point only the tabBar is visible.
    controller.jumpTo(600.0);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(tabBarHeight(tester), initialTabBarHeight);
    expect(appBarHeight(tester), lessThan(initialAppBarHeight));
    expect(appBarHeight(tester), initialTabBarHeight);

    // Scroll the floating-pinned appbar back into view
    controller.jumpTo(0.0);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), initialAppBarHeight);
    expect(tabBarHeight(tester), initialTabBarHeight);
  });

  testWidgets('SliverAppBar expandedHeight, floating with snap:true', (WidgetTester tester) async {
    await tester.pumpWidget(buildSliverAppBarApp(
      floating: true,
      snap: true,
      expandedHeight: 128.0,
    ));
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarTop(tester), 0.0);
    expect(appBarHeight(tester), 128.0);
    expect(appBarBottom(tester), 128.0);

    // Scroll to the middle of the list. The (floating) appbar is no longer visible.
    final ScrollPosition position = tester.state<ScrollableState>(find.byType(Scrollable)).position;
    position.jumpTo(256.00);
    await tester.pumpAndSettle();
    expect(find.byType(SliverAppBar), findsNothing);
    expect(appBarTop(tester), lessThanOrEqualTo(-128.0));

    // Drag the scrollable up and down. The app bar should not snap open, its
    // height should just track the drag offset.
    TestGesture gesture = await tester.startGesture(const Offset(50.0, 256.0));
    await gesture.moveBy(const Offset(0.0, 128.0)); // drag the appbar all the way open
    await tester.pump();
    expect(appBarTop(tester), 0.0);
    expect(appBarHeight(tester), 128.0);

    await gesture.moveBy(const Offset(0.0, -50.0));
    await tester.pump();
    expect(appBarBottom(tester), 78.0); // 78 == 128 - 50

    // Trigger the snap open animation: drag down and release
    await gesture.moveBy(const Offset(0.0, 10.0));
    await gesture.up();

    // Now verify that the appbar is animating open
    await tester.pump();
    await tester.pump(const Duration(milliseconds: 50));
    double bottom = appBarBottom(tester);
    expect(bottom, greaterThan(88.0)); // 88 = 78 + 10

    await tester.pump();
    await tester.pump(const Duration(milliseconds: 50));
    expect(appBarBottom(tester), greaterThan(bottom));

    // The animation finishes when the appbar is full height.
    await tester.pumpAndSettle();
    expect(appBarHeight(tester), 128.0);

    // Now that the app bar is open, perform the same drag scenario
    // in reverse: drag the appbar up and down and then trigger the
    // snap closed animation.
    gesture = await tester.startGesture(const Offset(50.0, 256.0));
    await gesture.moveBy(const Offset(0.0, -128.0)); // drag the appbar closed
    await tester.pump();
    expect(appBarBottom(tester), 0.0);

    await gesture.moveBy(const Offset(0.0, 100.0));
    await tester.pump();
    expect(appBarBottom(tester), 100.0);

    // Trigger the snap close animation: drag upwards and release
    await gesture.moveBy(const Offset(0.0, -10.0));
    await gesture.up();

    // Now verify that the appbar is animating closed
    await tester.pump();
    await tester.pump(const Duration(milliseconds: 50));
    bottom = appBarBottom(tester);
    expect(bottom, lessThan(90.0));

    await tester.pump();
    await tester.pump(const Duration(milliseconds: 50));
    expect(appBarBottom(tester), lessThan(bottom));

    // The animation finishes when the appbar is off screen.
    await tester.pumpAndSettle();
    expect(appBarTop(tester), lessThanOrEqualTo(0.0));
    expect(appBarBottom(tester), lessThanOrEqualTo(0.0));
  });

  testWidgets('SliverAppBar expandedHeight, floating and pinned with snap:true', (WidgetTester tester) async {
    await tester.pumpWidget(buildSliverAppBarApp(
      floating: true,
      pinned: true,
      snap: true,
      expandedHeight: 128.0,
    ));
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarTop(tester), 0.0);
    expect(appBarHeight(tester), 128.0);
    expect(appBarBottom(tester), 128.0);

    // Scroll to the middle of the list. The only the tab bar is visible
    // because this is a pinned appbar.
    final ScrollPosition position = tester.state<ScrollableState>(find.byType(Scrollable)).position;
    position.jumpTo(256.0);
    await tester.pumpAndSettle();
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarTop(tester), 0.0);
    expect(appBarHeight(tester), kTextTabBarHeight);

    // Drag the scrollable up and down. The app bar should not snap open, the
    // bottom of the appbar should just track the drag offset.
    TestGesture gesture = await tester.startGesture(const Offset(50.0, 200.0));
    await gesture.moveBy(const Offset(0.0, 100.0));
    await tester.pump();
    expect(appBarHeight(tester), 100.0);

    await gesture.moveBy(const Offset(0.0, -25.0));
    await tester.pump();
    expect(appBarHeight(tester), 75.0);

    // Trigger the snap animation: drag down and release
    await gesture.moveBy(const Offset(0.0, 10.0));
    await gesture.up();

    // Now verify that the appbar is animating open
    await tester.pump();
    await tester.pump(const Duration(milliseconds: 50));
    final double height = appBarHeight(tester);
    expect(height, greaterThan(85.0));
    expect(height, lessThan(128.0));

    await tester.pump();
    await tester.pump(const Duration(milliseconds: 50));
    expect(appBarHeight(tester), greaterThan(height));
    expect(appBarHeight(tester), lessThan(128.0));

    // The animation finishes when the appbar is fully expanded
    await tester.pumpAndSettle();
    expect(appBarTop(tester), 0.0);
    expect(appBarHeight(tester), 128.0);
    expect(appBarBottom(tester), 128.0);

    // Now that the appbar is fully expanded, Perform the same drag
    // scenario in reverse: drag the appbar up and down and then trigger
    // the snap closed animation.
    gesture = await tester.startGesture(const Offset(50.0, 256.0));
    await gesture.moveBy(const Offset(0.0, -128.0));
    await tester.pump();
    expect(appBarBottom(tester), kTextTabBarHeight);

    await gesture.moveBy(const Offset(0.0, 100.0));
    await tester.pump();
    expect(appBarBottom(tester), 100.0);

    // Trigger the snap close animation: drag upwards and release
    await gesture.moveBy(const Offset(0.0, -10.0));
    await gesture.up();

    // Now verify that the appbar is animating closed
    await tester.pump();
    await tester.pump(const Duration(milliseconds: 50));
    final double bottom = appBarBottom(tester);
    expect(bottom, lessThan(90.0));

    await tester.pump();
    await tester.pump(const Duration(milliseconds: 50));
    expect(appBarBottom(tester), lessThan(bottom));

    // The animation finishes when the appbar shrinks back to its pinned height
    await tester.pumpAndSettle();
    expect(appBarTop(tester), lessThanOrEqualTo(0.0));
    expect(appBarBottom(tester), kTextTabBarHeight);
  });

  testWidgets('SliverAppBar expandedHeight, collapsedHeight', (WidgetTester tester) async {
    const double expandedAppBarHeight = 400.0;
    const double collapsedAppBarHeight = 200.0;

    await tester.pumpWidget(buildSliverAppBarApp(
      collapsedHeight: collapsedAppBarHeight,
      expandedHeight: expandedAppBarHeight,
    ));

    final ScrollController controller = primaryScrollController(tester);
    expect(controller.offset, 0.0);
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), expandedAppBarHeight);

    final double initialTabBarHeight = tabBarHeight(tester);

    // Scroll the not-pinned appbar partially out of view.
    controller.jumpTo(50.0);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), expandedAppBarHeight - 50.0);
    expect(tabBarHeight(tester), initialTabBarHeight);

    // Scroll the not-pinned appbar out of view, to its collapsed height.
    controller.jumpTo(600.0);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsNothing);
    expect(appBarHeight(tester), collapsedAppBarHeight + initialTabBarHeight);
    expect(tabBarHeight(tester), initialTabBarHeight);

    // Scroll the not-pinned appbar back into view.
    controller.jumpTo(0.0);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), expandedAppBarHeight);
    expect(tabBarHeight(tester), initialTabBarHeight);
  });

  testWidgets('SliverAppBar.medium defaults', (WidgetTester tester) async {
    const double collapsedAppBarHeight = 64;
    const double expandedAppBarHeight = 112;

    await tester.pumpWidget(MaterialApp(
      home: Scaffold(
        body: CustomScrollView(
          primary: true,
          slivers: <Widget>[
            SliverAppBar.medium(
              title: const Text('AppBar Title'),
            ),
            SliverToBoxAdapter(
              child: Container(
                height: 1200,
                color: Colors.orange[400],
              ),
            ),
          ],
        ),
      ),
    ));

    final ScrollController controller = primaryScrollController(tester);
    // There are two widgets for the title. The first is the title on the main
    // row with the icons. It is transparent when the app bar is expanded, and
    // opaque when it is collapsed. The second title is a larger version that is
    // shown at the bottom when the app bar is expanded. It scrolls under the
    // main row until it is completely hidden and then the first title is faded
    // in.
    final Finder collapsedTitle = find.text('AppBar Title').first;
    final Finder collapsedTitleOpacity = find.ancestor(
      of: collapsedTitle,
      matching: find.byType(AnimatedOpacity),
    );
    final Finder expandedTitle = find.text('AppBar Title').last;
    final Finder expandedTitleClip = find.ancestor(
      of: expandedTitle,
      matching: find.byType(ClipRect),
    );

    // Default, fully expanded app bar.
    expect(controller.offset, 0);
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), expandedAppBarHeight);
    expect(tester.widget<AnimatedOpacity>(collapsedTitleOpacity).opacity, 0);
    expect(tester.getSize(expandedTitleClip).height, expandedAppBarHeight - collapsedAppBarHeight);

    // Scroll the expanded app bar partially out of view.
    controller.jumpTo(45);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), expandedAppBarHeight - 45);
    expect(tester.widget<AnimatedOpacity>(collapsedTitleOpacity).opacity, 0);
    expect(tester.getSize(expandedTitleClip).height, expandedAppBarHeight - collapsedAppBarHeight - 45);

    // Scroll so that it is completely collapsed.
    controller.jumpTo(600);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), collapsedAppBarHeight);
    expect(tester.widget<AnimatedOpacity>(collapsedTitleOpacity).opacity, 1);
    expect(tester.getSize(expandedTitleClip).height, 0);

    // Scroll back to fully expanded.
    controller.jumpTo(0);
    await tester.pumpAndSettle();
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), expandedAppBarHeight);
    expect(tester.widget<AnimatedOpacity>(collapsedTitleOpacity).opacity, 0);
    expect(tester.getSize(expandedTitleClip).height, expandedAppBarHeight - collapsedAppBarHeight);
  });

  testWidgets('SliverAppBar.large defaults', (WidgetTester tester) async {
    const double collapsedAppBarHeight = 64;
    const double expandedAppBarHeight = 152;

    await tester.pumpWidget(MaterialApp(
      home: Scaffold(
        body: CustomScrollView(
          primary: true,
          slivers: <Widget>[
            SliverAppBar.large(
              title: const Text('AppBar Title'),
            ),
            SliverToBoxAdapter(
              child: Container(
                height: 1200,
                color: Colors.orange[400],
              ),
            ),
          ],
        ),
      ),
    ));

    final ScrollController controller = primaryScrollController(tester);
    // There are two widgets for the title. The first is the title on the main
    // row with the icons. It is transparent when the app bar is expanded, and
    // opaque when it is collapsed. The second title is a larger version that is
    // shown at the bottom when the app bar is expanded. It scrolls under the
    // main row until it is completely hidden and then the first title is faded
    // in.
    final Finder collapsedTitle = find.text('AppBar Title').first;
    final Finder collapsedTitleOpacity = find.ancestor(
      of: collapsedTitle,
      matching: find.byType(AnimatedOpacity),
    );
    final Finder expandedTitle = find.text('AppBar Title').last;
    final Finder expandedTitleClip = find.ancestor(
      of: expandedTitle,
      matching: find.byType(ClipRect),
    );

    // Default, fully expanded app bar.
    expect(controller.offset, 0);
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), expandedAppBarHeight);
    expect(tester.widget<AnimatedOpacity>(collapsedTitleOpacity).opacity, 0);
    expect(tester.getSize(expandedTitleClip).height, expandedAppBarHeight - collapsedAppBarHeight);

    // Scroll the expanded app bar partially out of view.
    controller.jumpTo(45);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), expandedAppBarHeight - 45);
    expect(tester.widget<AnimatedOpacity>(collapsedTitleOpacity).opacity, 0);
    expect(tester.getSize(expandedTitleClip).height, expandedAppBarHeight - collapsedAppBarHeight - 45);

    // Scroll so that it is completely collapsed.
    controller.jumpTo(600);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), collapsedAppBarHeight);
    expect(tester.widget<AnimatedOpacity>(collapsedTitleOpacity).opacity, 1);
    expect(tester.getSize(expandedTitleClip).height, 0);

    // Scroll back to fully expanded.
    controller.jumpTo(0);
    await tester.pumpAndSettle();
    expect(find.byType(SliverAppBar), findsOneWidget);
    expect(appBarHeight(tester), expandedAppBarHeight);
    expect(tester.widget<AnimatedOpacity>(collapsedTitleOpacity).opacity, 0);
    expect(tester.getSize(expandedTitleClip).height, expandedAppBarHeight - collapsedAppBarHeight);
  });

  testWidgets('AppBar uses the specified elevation or defaults to 4.0', (WidgetTester tester) async {
    final bool useMaterial3 = ThemeData().useMaterial3;

    Widget buildAppBar([double? elevation]) {
      return MaterialApp(
        home: Scaffold(
          appBar: AppBar(title: const Text('Title'), elevation: elevation),
        ),
      );
    }

    Material getMaterial() => tester.widget<Material>(find.descendant(
      of: find.byType(AppBar),
      matching: find.byType(Material),
    ));

    // Default elevation should be used for the material.
    await tester.pumpWidget(buildAppBar());
    expect(getMaterial().elevation, useMaterial3 ? 0 : 4);

    // AppBar should use the specified elevation.
    await tester.pumpWidget(buildAppBar(8.0));
    expect(getMaterial().elevation, 8.0);
  });

  testWidgets('scrolledUnderElevation', (WidgetTester tester) async {
    Widget buildAppBar({double? elevation, double? scrolledUnderElevation}) {
      return MaterialApp(
        home: Scaffold(
          appBar: AppBar(
            title: const Text('Title'),
            elevation: elevation,
            scrolledUnderElevation: scrolledUnderElevation,
          ),
          body: ListView.builder(
            itemCount: 100,
            itemBuilder: (BuildContext context, int index) => ListTile(title: Text('Item $index')),
          ),
        ),
      );
    }

    Material getMaterial() => tester.widget<Material>(find.descendant(
      of: find.byType(AppBar),
      matching: find.byType(Material),
    ));

    await tester.pumpWidget(buildAppBar(elevation: 2, scrolledUnderElevation: 10));
    // Starts with the base elevation.
    expect(getMaterial().elevation, 2);

    await tester.fling(find.text('Item 2'), const Offset(0.0, -600.0), 2000.0);
    await tester.pumpAndSettle();

    // After scrolling it should be the scrolledUnderElevation.
    expect(getMaterial().elevation, 10);
  });

  testWidgets('scrolledUnderElevation with nested scroll view', (WidgetTester tester) async {
    Widget buildAppBar({double? scrolledUnderElevation}) {
      return MaterialApp(
        theme: ThemeData(useMaterial3: true),
        home: Scaffold(
          appBar: AppBar(
            title: const Text('Title'),
            scrolledUnderElevation: scrolledUnderElevation,
            notificationPredicate: (ScrollNotification notification) {
              return notification.depth == 1;
            },
          ),
          body: ListView.builder(
            scrollDirection: Axis.horizontal,
            itemCount: 4,
            itemBuilder: (BuildContext context, int index) {
              return SizedBox(
                height: 600.0,
                width: 800.0,
                child: ListView.builder(
                  itemCount: 100,
                  itemBuilder: (BuildContext context, int index) =>
                    ListTile(title: Text('Item $index')),
                ),
              );
            },
          ),
        ),
      );
    }

    Material getMaterial() => tester.widget<Material>(find.descendant(
      of: find.byType(AppBar),
      matching: find.byType(Material),
    ));

    await tester.pumpWidget(buildAppBar(scrolledUnderElevation: 10));
    // Starts with the base elevation.
    expect(getMaterial().elevation, 0.0);

    await tester.fling(find.text('Item 2'), const Offset(0.0, -600.0), 2000.0);
    await tester.pumpAndSettle();

    // After scrolling it should be the scrolledUnderElevation.
    expect(getMaterial().elevation, 10);
  });

  group('SliverAppBar elevation', () {
    Widget buildSliverAppBar(bool forceElevated, {double? elevation, double? themeElevation}) {
      return MaterialApp(
        theme: ThemeData(appBarTheme: AppBarTheme(elevation: themeElevation)),
        home: CustomScrollView(
          slivers: <Widget>[
            SliverAppBar(
              title: const Text('Title'),
              forceElevated: forceElevated,
              elevation: elevation,
            ),
          ],
        ),
      );
    }

    testWidgets('Respects forceElevated parameter', (WidgetTester tester) async {
      // Regression test for https://github.com/flutter/flutter/issues/59158.
      AppBar getAppBar() => tester.widget<AppBar>(find.byType(AppBar));
      Material getMaterial() => tester.widget<Material>(find.byType(Material));
      final bool useMaterial3 = ThemeData().useMaterial3;

      // When forceElevated is off, SliverAppBar should not be elevated.
      await tester.pumpWidget(buildSliverAppBar(false));
      expect(getMaterial().elevation, 0.0);

      // Default elevation should be used by the material, but
      // the AppBar's elevation should not be specified by SliverAppBar.
      await tester.pumpWidget(buildSliverAppBar(true));
      expect(getMaterial().elevation, useMaterial3 ? 0.0 : 4.0);
      expect(getAppBar().elevation, null);

      // SliverAppBar should use the specified elevation.
      await tester.pumpWidget(buildSliverAppBar(true, elevation: 8.0));
      expect(getMaterial().elevation, 8.0);
    });

    testWidgets('Uses elevation of AppBarTheme by default', (WidgetTester tester) async {
      // Regression test for https://github.com/flutter/flutter/issues/73525.
      Material getMaterial() => tester.widget<Material>(find.byType(Material));

      await tester.pumpWidget(buildSliverAppBar(false, themeElevation: 12.0));
      expect(getMaterial().elevation, 0.0);

      await tester.pumpWidget(buildSliverAppBar(true, themeElevation: 12.0));
      expect(getMaterial().elevation, 12.0);

      await tester.pumpWidget(buildSliverAppBar(true, elevation: 8.0, themeElevation: 12.0));
      expect(getMaterial().elevation, 8.0);
    });
  });

  group('SliverAppBar.forceMaterialTransparency', () {
    Material getSliverAppBarMaterial(WidgetTester tester) {
      return tester.widget<Material>(find
          .descendant(of: find.byType(SliverAppBar), matching: find.byType(Material))
          .first);
    }

    // Generates a MaterialApp with a SliverAppBar in a CustomScrollView.
    // The first cell of the scroll view contains a button at its top, and is
    // initially scrolled so that it is beneath the SliverAppBar.
    Widget buildWidget({
      required bool forceMaterialTransparency,
      required VoidCallback onPressed
    }) {
      const double appBarHeight = 120;
      return MaterialApp(
        home: Scaffold(
          body: CustomScrollView(
            controller: ScrollController(initialScrollOffset:appBarHeight),
            slivers: <Widget>[
              SliverAppBar(
                collapsedHeight: appBarHeight,
                expandedHeight: appBarHeight,
                pinned: true,
                elevation: 0,
                backgroundColor: Colors.transparent,
                forceMaterialTransparency: forceMaterialTransparency,
                title: const Text('AppBar'),
              ),
              SliverList(
                delegate: SliverChildBuilderDelegate((BuildContext context, int index) {
                  return SizedBox(
                    height: appBarHeight,
                    child: index == 0
                      ? Align(
                          alignment: Alignment.topCenter,
                          child: TextButton(onPressed: onPressed, child: const Text('press')))
                      : const SizedBox(),
                  );
                },
                childCount: 20,
              ),
            ),
          ]),
        ),
      );
    }

    testWidgets(
        'forceMaterialTransparency == true allows gestures beneath the app bar', (WidgetTester tester) async {
      bool buttonWasPressed = false;
      final Widget widget = buildWidget(
        forceMaterialTransparency:true,
        onPressed:() { buttonWasPressed = true; },
      );
      await tester.pumpWidget(widget);

      final Material material = getSliverAppBarMaterial(tester);
      expect(material.type, MaterialType.transparency);

      final Finder buttonFinder = find.byType(TextButton);
      await tester.tap(buttonFinder);
      await tester.pump();
      expect(buttonWasPressed, isTrue);
    });

    testWidgets(
        'forceMaterialTransparency == false does not allow gestures beneath the app bar', (WidgetTester tester) async {
      // Set this, and tester.tap(warnIfMissed:false), to suppress
      // errors/warning that the button is not hittable (which is expected).
      WidgetController.hitTestWarningShouldBeFatal = false;

      bool buttonWasPressed = false;
      final Widget widget = buildWidget(
        forceMaterialTransparency:false,
        onPressed:() { buttonWasPressed = true; },
      );
      await tester.pumpWidget(widget);

      final Material material = getSliverAppBarMaterial(tester);
      expect(material.type, MaterialType.canvas);

      final Finder buttonFinder = find.byType(TextButton);
      await tester.tap(buttonFinder, warnIfMissed:false);
      await tester.pump();
      expect(buttonWasPressed, isFalse);
    });
  });

  testWidgets('AppBar dimensions, with and without bottom, primary', (WidgetTester tester) async {
    const MediaQueryData topPadding100 = MediaQueryData(padding: EdgeInsets.only(top: 100.0));

    await tester.pumpWidget(
      Localizations(
        locale: const Locale('en', 'US'),
        delegates: const <LocalizationsDelegate<dynamic>>[
          DefaultMaterialLocalizations.delegate,
          DefaultWidgetsLocalizations.delegate,
        ],
        child: Directionality(
          textDirection: TextDirection.ltr,
          child: MediaQuery(
            data: topPadding100,
            child: Scaffold(
              primary: false,
              appBar: AppBar(),
            ),
          ),
        ),
      ),
    );
    expect(appBarTop(tester), 0.0);
    expect(appBarHeight(tester), kToolbarHeight);

    await tester.pumpWidget(
      Localizations(
        locale: const Locale('en', 'US'),
        delegates: const <LocalizationsDelegate<dynamic>>[
          DefaultMaterialLocalizations.delegate,
          DefaultWidgetsLocalizations.delegate,
        ],
        child: Directionality(
          textDirection: TextDirection.ltr,
          child: MediaQuery(
            data: topPadding100,
            child: Scaffold(
              appBar: AppBar(
                title: const Text('title'),
              ),
            ),
          ),
        ),
      ),
    );
    expect(appBarTop(tester), 0.0);
    expect(tester.getTopLeft(find.text('title')).dy, greaterThan(100.0));
    expect(appBarHeight(tester), kToolbarHeight + 100.0);

    await tester.pumpWidget(
      Localizations(
        locale: const Locale('en', 'US'),
        delegates: const <LocalizationsDelegate<dynamic>>[
          DefaultMaterialLocalizations.delegate,
          DefaultWidgetsLocalizations.delegate,
        ],
        child: Directionality(
          textDirection: TextDirection.ltr,
          child: MediaQuery(
            data: topPadding100,
            child: Scaffold(
              primary: false,
              appBar: AppBar(
                bottom: PreferredSize(
                  preferredSize: const Size.fromHeight(200.0),
                  child: Container(),
                ),
              ),
            ),
          ),
        ),
      ),
    );
    expect(appBarTop(tester), 0.0);
    expect(appBarHeight(tester), kToolbarHeight + 200.0);

    await tester.pumpWidget(
      Localizations(
        locale: const Locale('en', 'US'),
        delegates: const <LocalizationsDelegate<dynamic>>[
          DefaultMaterialLocalizations.delegate,
          DefaultWidgetsLocalizations.delegate,
        ],
        child: Directionality(
          textDirection: TextDirection.ltr,
          child: MediaQuery(
            data: topPadding100,
            child: Scaffold(
              appBar: AppBar(
                bottom: PreferredSize(
                  preferredSize: const Size.fromHeight(200.0),
                  child: Container(),
                ),
              ),
            ),
          ),
        ),
      ),
    );
    expect(appBarTop(tester), 0.0);
    expect(appBarHeight(tester), kToolbarHeight + 100.0 + 200.0);

    await tester.pumpWidget(
      Localizations(
        locale: const Locale('en', 'US'),
        delegates: const <LocalizationsDelegate<dynamic>>[
          DefaultMaterialLocalizations.delegate,
          DefaultWidgetsLocalizations.delegate,
        ],
        child: Directionality(
          textDirection: TextDirection.ltr,
          child: MediaQuery(
            data: topPadding100,
            child: AppBar(
              primary: false,
              title: const Text('title'),
            ),
          ),
        ),
      ),
    );
    expect(appBarTop(tester), 0.0);
    expect(tester.getTopLeft(find.text('title')).dy, lessThan(100.0));
  });

  testWidgets('AppBar in body excludes bottom SafeArea padding', (WidgetTester tester) async {
    // Regression test for https://github.com/flutter/flutter/issues/26163
    await tester.pumpWidget(
      Localizations(
        locale: const Locale('en', 'US'),
        delegates: const <LocalizationsDelegate<dynamic>>[
          DefaultMaterialLocalizations.delegate,
          DefaultWidgetsLocalizations.delegate,
        ],
        child: Directionality(
          textDirection: TextDirection.ltr,
          child: MediaQuery(
            data: const MediaQueryData(padding: EdgeInsets.symmetric(vertical: 100.0)),
            child: Scaffold(
              body: Column(
                children: <Widget>[
                  AppBar(
                    title: const Text('title'),
                  ),
                ],
              ),
            ),
          ),
        ),
      ),
    );
    expect(appBarTop(tester), 0.0);
    expect(appBarHeight(tester), kToolbarHeight + 100.0);
  });

  testWidgets('AppBar updates when you add a drawer', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        home: Scaffold(
          appBar: AppBar(),
        ),
      ),
    );
    expect(find.byIcon(Icons.menu), findsNothing);
    await tester.pumpWidget(
      MaterialApp(
        home: Scaffold(
          drawer: const Drawer(),
          appBar: AppBar(),
        ),
      ),
    );
    expect(find.byIcon(Icons.menu), findsOneWidget);
  });

  testWidgets('AppBar does not draw menu for drawer if automaticallyImplyLeading is false', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        home: Scaffold(
          drawer: const Drawer(),
          appBar: AppBar(
            automaticallyImplyLeading: false,
          ),
        ),
      ),
    );
    expect(find.byIcon(Icons.menu), findsNothing);
  });

  testWidgets('AppBar does not update the leading if a route is popped case 1', (WidgetTester tester) async {
    final Page<void> page1 = MaterialPage<void>(
      key: const ValueKey<String>('1'),
      child: Scaffold(
        key: const ValueKey<String>('1'),
        appBar: AppBar(),
      ),
    );
    final Page<void> page2 = MaterialPage<void>(
        key: const ValueKey<String>('2'),
        child: Scaffold(
          key: const ValueKey<String>('2'),
          appBar: AppBar(),
        ),
    );
    List<Page<void>> pages = <Page<void>>[ page1 ];
    await tester.pumpWidget(
      MaterialApp(
        home: Navigator(
          pages: pages,
          onPopPage: (Route<dynamic> route, dynamic result) => false,
        ),
      ),
    );
    expect(find.byType(BackButton), findsNothing);
    // Update pages
    pages = <Page<void>>[ page2 ];
    await tester.pumpWidget(
      MaterialApp(
        home: Navigator(
          pages: pages,
          onPopPage: (Route<dynamic> route, dynamic result) => false,
        ),
      ),
    );
    expect(find.byType(BackButton), findsNothing);
  });

  testWidgets('AppBar does not update the leading if a route is popped case 2', (WidgetTester tester) async {
    final Page<void> page1 = MaterialPage<void>(
      key: const ValueKey<String>('1'),
      child: Scaffold(
        key: const ValueKey<String>('1'),
        appBar: AppBar(),
      ),
    );
    final Page<void> page2 = MaterialPage<void>(
      key: const ValueKey<String>('2'),
      child: Scaffold(
        key: const ValueKey<String>('2'),
        appBar: AppBar(),
      ),
    );
    List<Page<void>> pages = <Page<void>>[ page1, page2 ];
    await tester.pumpWidget(
      MaterialApp(
        home: Navigator(
          pages: pages,
          onPopPage: (Route<dynamic> route, dynamic result) => false,
        ),
      ),
    );
    // The page2 should have a back button
    expect(
      find.descendant(
        of: find.byKey(const ValueKey<String>('2')),
        matching: find.byType(BackButton),
      ),
      findsOneWidget,
    );
    // Update pages
    pages = <Page<void>>[ page1 ];
    await tester.pumpWidget(
      MaterialApp(
        home: Navigator(
          pages: pages,
          onPopPage: (Route<dynamic> route, dynamic result) => false,
        ),
      ),
    );
    await tester.pump(const Duration(milliseconds: 10));
    // The back button should persist during the pop animation.
    expect(
      find.descendant(
        of: find.byKey(const ValueKey<String>('2')),
        matching: find.byType(BackButton),
      ),
      findsOneWidget,
    );
  });

  testWidgets('AppBar ink splash draw on the correct canvas', (WidgetTester tester) async {
    // This is a regression test for https://github.com/flutter/flutter/issues/58665
    final Key key = UniqueKey();
    await tester.pumpWidget(
      MaterialApp(
        // Test was designed against InkSplash so need to make sure that is used.
        theme: ThemeData(splashFactory: InkSplash.splashFactory),
        home: Center(
          child: AppBar(
            title: const Text('Abc'),
            actions: <Widget>[
              IconButton(
                key: key,
                icon: const Icon(Icons.add_circle),
                tooltip: 'First button',
                onPressed: () {},
              ),
            ],
            flexibleSpace: DecoratedBox(
              decoration: BoxDecoration(
                gradient: LinearGradient(
                  begin: Alignment.topCenter,
                  end: const Alignment(-0.04, 1.0),
                  colors: <Color>[Colors.blue.shade500, Colors.blue.shade800],
                ),
              ),
            ),
          ),
        ),
      ),
    );
    final RenderObject painter = tester.renderObject(
      find.descendant(
        of: find.descendant(
          of: find.byType(AppBar),
          matching: find.byType(Stack),
        ),
        matching: find.byType(Material),
      ),
    );
    await tester.tap(find.byKey(key));
    expect(painter, paints..save()..translate()..save()..translate()..circle(x: 24.0, y: 28.0));
  });

  testWidgets('AppBar handles loose children 0', (WidgetTester tester) async {
    final GlobalKey key = GlobalKey();
    await tester.pumpWidget(
      MaterialApp(
        home: Center(
          child: AppBar(
            leading: Placeholder(key: key),
            title: const Text('Abc'),
            actions: const <Widget>[
              Placeholder(fallbackWidth: 10.0),
              Placeholder(fallbackWidth: 10.0),
              Placeholder(fallbackWidth: 10.0),
            ],
          ),
        ),
      ),
    );
    expect(tester.renderObject<RenderBox>(find.byKey(key)).localToGlobal(Offset.zero), Offset.zero);
    expect(tester.renderObject<RenderBox>(find.byKey(key)).size, const Size(56.0, 56.0));
  });

  testWidgets('AppBar handles loose children 1', (WidgetTester tester) async {
    final GlobalKey key = GlobalKey();
    await tester.pumpWidget(
      MaterialApp(
        home: Center(
          child: AppBar(
            leading: Placeholder(key: key),
            title: const Text('Abc'),
            actions: const <Widget>[
              Placeholder(fallbackWidth: 10.0),
              Placeholder(fallbackWidth: 10.0),
              Placeholder(fallbackWidth: 10.0),
            ],
            flexibleSpace: DecoratedBox(
              decoration: BoxDecoration(
                gradient: LinearGradient(
                  begin: Alignment.topCenter,
                  end: const Alignment(-0.04, 1.0),
                  colors: <Color>[Colors.blue.shade500, Colors.blue.shade800],
                ),
              ),
            ),
          ),
        ),
      ),
    );
    expect(tester.renderObject<RenderBox>(find.byKey(key)).localToGlobal(Offset.zero), Offset.zero);
    expect(tester.renderObject<RenderBox>(find.byKey(key)).size, const Size(56.0, 56.0));
  });

  testWidgets('AppBar handles loose children 2', (WidgetTester tester) async {
    final GlobalKey key = GlobalKey();
    await tester.pumpWidget(
      MaterialApp(
        home: Center(
          child: AppBar(
            leading: Placeholder(key: key),
            title: const Text('Abc'),
            actions: const <Widget>[
              Placeholder(fallbackWidth: 10.0),
              Placeholder(fallbackWidth: 10.0),
              Placeholder(fallbackWidth: 10.0),
            ],
            flexibleSpace: DecoratedBox(
              decoration: BoxDecoration(
                gradient: LinearGradient(
                  begin: Alignment.topCenter,
                  end: const Alignment(-0.04, 1.0),
                  colors: <Color>[Colors.blue.shade500, Colors.blue.shade800],
                ),
              ),
            ),
            bottom: PreferredSize(
              preferredSize: const Size(0.0, kToolbarHeight),
              child: Container(
                height: 50.0,
                padding: const EdgeInsets.all(4.0),
                child: const Placeholder(
                  color: Color(0xFFFFFFFF),
                ),
              ),
            ),
          ),
        ),
      ),
    );
    expect(tester.renderObject<RenderBox>(find.byKey(key)).localToGlobal(Offset.zero), Offset.zero);
    expect(tester.renderObject<RenderBox>(find.byKey(key)).size, const Size(56.0, 56.0));
  });

  testWidgets('AppBar handles loose children 3', (WidgetTester tester) async {
    final GlobalKey key = GlobalKey();
    await tester.pumpWidget(
      MaterialApp(
        home: Center(
          child: AppBar(
            leading: Placeholder(key: key),
            title: const Text('Abc'),
            actions: const <Widget>[
              Placeholder(fallbackWidth: 10.0),
              Placeholder(fallbackWidth: 10.0),
              Placeholder(fallbackWidth: 10.0),
            ],
            bottom: PreferredSize(
              preferredSize: const Size(0.0, kToolbarHeight),
              child: Container(
                height: 50.0,
                padding: const EdgeInsets.all(4.0),
                child: const Placeholder(
                  color: Color(0xFFFFFFFF),
                ),
              ),
            ),
          ),
        ),
      ),
    );
    expect(tester.renderObject<RenderBox>(find.byKey(key)).localToGlobal(Offset.zero), Offset.zero);
    expect(tester.renderObject<RenderBox>(find.byKey(key)).size, const Size(56.0, 56.0));
  });

  testWidgets('AppBar positioning of leading and trailing widgets with top padding', (WidgetTester tester) async {
    const MediaQueryData topPadding100 = MediaQueryData(padding: EdgeInsets.only(top: 100));

    final Key leadingKey = UniqueKey();
    final Key titleKey = UniqueKey();
    final Key trailingKey = UniqueKey();

    await tester.pumpWidget(
      Localizations(
        locale: const Locale('en', 'US'),
        delegates: const <LocalizationsDelegate<dynamic>>[
          DefaultMaterialLocalizations.delegate,
          DefaultWidgetsLocalizations.delegate,
        ],
        child: Directionality(
          textDirection: TextDirection.rtl,
          child: MediaQuery(
            data: topPadding100,
            child: Scaffold(
              primary: false,
              appBar: AppBar(
                leading: Placeholder(key: leadingKey), // Forced to 56x56, see _kLeadingWidth in app_bar.dart.
                title: Placeholder(key: titleKey, fallbackHeight: kToolbarHeight),
                actions: <Widget>[ Placeholder(key: trailingKey, fallbackWidth: 10) ],
              ),
            ),
          ),
        ),
      ),
    );
    expect(tester.getTopLeft(find.byType(AppBar)), Offset.zero);
    expect(tester.getTopLeft(find.byKey(leadingKey)), const Offset(800.0 - 56.0, 100));
    expect(tester.getTopLeft(find.byKey(trailingKey)), const Offset(0.0, 100));

    // Because the topPadding eliminates the vertical space for the
    // NavigationToolbar within the AppBar, the toolbar is constrained
    // with minHeight=maxHeight=0. The _AppBarTitle widget vertically centers
    // the title, so its Y coordinate relative to the toolbar is -kToolbarHeight / 2
    // (-28). The top of the toolbar is at (screen coordinates) y=100, so the
    // top of the title is 100 + -28 = 72. The toolbar clips its contents
    // so the title isn't actually visible.
    expect(tester.getTopLeft(find.byKey(titleKey)), const Offset(10 + NavigationToolbar.kMiddleSpacing, 72));
  });

  testWidgets('SliverAppBar positioning of leading and trailing widgets with top padding', (WidgetTester tester) async {
    const MediaQueryData topPadding100 = MediaQueryData(padding: EdgeInsets.only(top: 100.0));

    final Key leadingKey = UniqueKey();
    final Key titleKey = UniqueKey();
    final Key trailingKey = UniqueKey();

    await tester.pumpWidget(
      Localizations(
        locale: const Locale('en', 'US'),
        delegates: const <LocalizationsDelegate<dynamic>>[
          DefaultMaterialLocalizations.delegate,
          DefaultWidgetsLocalizations.delegate,
        ],
        child: Directionality(
          textDirection: TextDirection.rtl,
          child: MediaQuery(
            data: topPadding100,
            child: CustomScrollView(
              primary: true,
              slivers: <Widget>[
                SliverAppBar(
                  leading: Placeholder(key: leadingKey),
                  title: Placeholder(key: titleKey, fallbackHeight: kToolbarHeight),
                  actions: <Widget>[ Placeholder(key: trailingKey) ],
                ),
              ],
            ),
          ),
        ),
      ),
    );
    expect(tester.getTopLeft(find.byType(AppBar)), Offset.zero);
    expect(tester.getTopLeft(find.byKey(leadingKey)), const Offset(800.0 - 56.0, 100.0));
    expect(tester.getTopLeft(find.byKey(titleKey)), const Offset(416.0, 100.0));
    expect(tester.getTopLeft(find.byKey(trailingKey)), const Offset(0.0, 100.0));
  });

  testWidgets('SliverAppBar positioning of leading and trailing widgets with bottom padding', (WidgetTester tester) async {
    const MediaQueryData topPadding100 = MediaQueryData(padding: EdgeInsets.only(top: 100.0, bottom: 50.0));

    final Key leadingKey = UniqueKey();
    final Key titleKey = UniqueKey();
    final Key trailingKey = UniqueKey();

    await tester.pumpWidget(
      Localizations(
        locale: const Locale('en', 'US'),
        delegates: const <LocalizationsDelegate<dynamic>>[
          DefaultMaterialLocalizations.delegate,
          DefaultWidgetsLocalizations.delegate,
        ],
        child: Directionality(
          textDirection: TextDirection.rtl,
          child: MediaQuery(
            data: topPadding100,
            child: CustomScrollView(
              primary: true,
              slivers: <Widget>[
                SliverAppBar(
                  leading: Placeholder(key: leadingKey),
                  title: Placeholder(key: titleKey),
                  actions: <Widget>[ Placeholder(key: trailingKey) ],
                ),
              ],
            ),
          ),
        ),
      ),
    );
    expect(tester.getRect(find.byType(AppBar)), const Rect.fromLTRB(0.0, 0.0, 800.00, 100.0 + 56.0));
    expect(tester.getRect(find.byKey(leadingKey)), const Rect.fromLTRB(800.0 - 56.0, 100.0, 800.0, 100.0 + 56.0));
    expect(tester.getRect(find.byKey(trailingKey)), const Rect.fromLTRB(0.0, 100.0, 400.0, 100.0 + 56.0));
  });

  testWidgets('SliverAppBar provides correct semantics in LTR', (WidgetTester tester) async {
    final SemanticsTester semantics = SemanticsTester(tester);

    await tester.pumpWidget(
      MaterialApp(
        home: Center(
          child: AppBar(
            leading: const Text('Leading'),
            title: const Text('Title'),
            actions: const <Widget>[
              Text('Action 1'),
              Text('Action 2'),
              Text('Action 3'),
            ],
            bottom: const PreferredSize(
              preferredSize: Size(0.0, kToolbarHeight),
              child: Text('Bottom'),
            ),
          ),
        ),
      ),
    );

    expect(semantics, hasSemantics(
      TestSemantics.root(
        children: <TestSemantics>[
          TestSemantics(
            children: <TestSemantics>[
              TestSemantics(
                children: <TestSemantics> [
                  TestSemantics(
                    flags: <SemanticsFlag>[SemanticsFlag.scopesRoute],
                    children: <TestSemantics>[
                      TestSemantics(
                        children: <TestSemantics>[
                          TestSemantics(
                            label: 'Leading',
                            textDirection: TextDirection.ltr,
                          ),
                          TestSemantics(
                            flags: <SemanticsFlag>[
                              SemanticsFlag.namesRoute,
                              SemanticsFlag.isHeader,
                            ],
                            label: 'Title',
                            textDirection: TextDirection.ltr,
                          ),
                          TestSemantics(
                            label: 'Action 1',
                            textDirection: TextDirection.ltr,
                          ),
                          TestSemantics(
                            label: 'Action 2',
                            textDirection: TextDirection.ltr,
                          ),
                          TestSemantics(
                            label: 'Action 3',
                            textDirection: TextDirection.ltr,
                          ),
                          TestSemantics(
                            label: 'Bottom',
                            textDirection: TextDirection.ltr,
                          ),
                        ],
                      ),
                    ],
                  ),
                ],
              ),
            ],
          ),
        ],
      ),
      ignoreRect: true,
      ignoreTransform: true,
      ignoreId: true,
    ));

    semantics.dispose();
  });

  testWidgets('SliverAppBar provides correct semantics in RTL', (WidgetTester tester) async {
    final SemanticsTester semantics = SemanticsTester(tester);

    await tester.pumpWidget(
      MaterialApp(
        home: Semantics(
          textDirection: TextDirection.rtl,
          child: Directionality(
            textDirection: TextDirection.rtl,
            child: Center(
              child: AppBar(
                leading: const Text('Leading'),
                title: const Text('Title'),
                actions: const <Widget>[
                  Text('Action 1'),
                  Text('Action 2'),
                  Text('Action 3'),
                ],
                bottom: const PreferredSize(
                  preferredSize: Size(0.0, kToolbarHeight),
                  child: Text('Bottom'),
                ),
              ),
            ),
          ),
        ),
      ),
    );

    expect(semantics, hasSemantics(
      TestSemantics.root(
        children: <TestSemantics>[
          TestSemantics(
            children: <TestSemantics>[
              TestSemantics(
                children: <TestSemantics>[
                  TestSemantics(
                    flags: <SemanticsFlag>[SemanticsFlag.scopesRoute],
                    children: <TestSemantics>[
                      TestSemantics(
                        textDirection: TextDirection.rtl,
                        children: <TestSemantics>[
                          TestSemantics(
                            children: <TestSemantics>[
                              TestSemantics(
                                label: 'Leading',
                                textDirection: TextDirection.rtl,
                              ),
                              TestSemantics(
                                flags: <SemanticsFlag>[
                                  SemanticsFlag.namesRoute,
                                  SemanticsFlag.isHeader,
                                ],
                                label: 'Title',
                                textDirection: TextDirection.rtl,
                              ),
                              TestSemantics(
                                label: 'Action 1',
                                textDirection: TextDirection.rtl,
                              ),
                              TestSemantics(
                                label: 'Action 2',
                                textDirection: TextDirection.rtl,
                              ),
                              TestSemantics(
                                label: 'Action 3',
                                textDirection: TextDirection.rtl,
                              ),
                              TestSemantics(
                                label: 'Bottom',
                                textDirection: TextDirection.rtl,
                              ),
                            ],
                          ),
                        ],
                      ),
                    ],
                  ),
                ],
              ),
            ],
          ),
        ],
      ),
      ignoreRect: true,
      ignoreTransform: true,
      ignoreId: true,
    ));

    semantics.dispose();
  });

  testWidgets('AppBar excludes header semantics correctly', (WidgetTester tester) async {
    final SemanticsTester semantics = SemanticsTester(tester);

    await tester.pumpWidget(
      MaterialApp(
        home: Center(
          child: AppBar(
            leading: const Text('Leading'),
            title: const ExcludeSemantics(child: Text('Title')),
            excludeHeaderSemantics: true,
            actions: const <Widget>[
              Text('Action 1'),
            ],
          ),
        ),
      ),
    );

    expect(semantics, hasSemantics(
      TestSemantics.root(
        children: <TestSemantics>[
          TestSemantics(
            children: <TestSemantics>[
              TestSemantics(
                children: <TestSemantics>[
                  TestSemantics(
                    flags: <SemanticsFlag>[SemanticsFlag.scopesRoute],
                    children: <TestSemantics>[
                      TestSemantics(
                        children: <TestSemantics>[
                          TestSemantics(
                            label: 'Leading',
                            textDirection: TextDirection.ltr,
                          ),
                          TestSemantics(
                            label: 'Action 1',
                            textDirection: TextDirection.ltr,
                          ),
                        ],
                      ),
                    ],
                  ),
                ],
              ),
            ],
          ),
        ],
      ),
      ignoreRect: true,
      ignoreTransform: true,
      ignoreId: true,
    ));

    semantics.dispose();
  });

  testWidgets('SliverAppBar excludes header semantics correctly', (WidgetTester tester) async {
    final SemanticsTester semantics = SemanticsTester(tester);

    await tester.pumpWidget(
      const MaterialApp(
        home: CustomScrollView(
          slivers: <Widget>[
            SliverAppBar(
              leading: Text('Leading'),
              flexibleSpace: ExcludeSemantics(child: Text('Title')),
              actions: <Widget>[Text('Action 1')],
              excludeHeaderSemantics: true,
            ),
          ],
        ),
      ),
    );

    expect(semantics, hasSemantics(
      TestSemantics.root(
        children: <TestSemantics>[
          TestSemantics(
            textDirection: TextDirection.ltr,
            children: <TestSemantics>[
              TestSemantics(
                children: <TestSemantics>[
                  TestSemantics(
                    flags: <SemanticsFlag>[SemanticsFlag.scopesRoute],
                    children: <TestSemantics>[
                      TestSemantics(
                        children: <TestSemantics>[
                          TestSemantics(
                            children: <TestSemantics>[
                              TestSemantics(
                                children: <TestSemantics>[
                                  TestSemantics(
                                    label: 'Leading',
                                    textDirection: TextDirection.ltr,
                                  ),
                                  TestSemantics(
                                    label: 'Action 1',
                                    textDirection: TextDirection.ltr,
                                  ),
                                ],
                              ),
                              TestSemantics(),
                            ],
                          ),
                          TestSemantics(
                            flags: <SemanticsFlag>[SemanticsFlag.hasImplicitScrolling],
                          ),
                        ],
                      ),
                    ],
                  ),
                ],
              ),
            ],
          ),
        ],
      ),
      ignoreRect: true,
      ignoreTransform: true,
      ignoreId: true,
    ));

    semantics.dispose();
  });

  testWidgets('SliverAppBar with flexible space has correct semantics order', (WidgetTester tester) async {
    // Regression test for https://github.com/flutter/flutter/issues/64922.
    final SemanticsTester semantics = SemanticsTester(tester);

    await tester.pumpWidget(
      const MaterialApp(
        home: CustomScrollView(
          slivers: <Widget>[
            SliverAppBar(
              leading: Text('Leading'),
              flexibleSpace: Text('Flexible space'),
              actions: <Widget>[Text('Action 1')],
            ),
          ],
        ),
      ),
    );

    expect(semantics, hasSemantics(
      TestSemantics.root(
        children: <TestSemantics>[
          TestSemantics(
            textDirection: TextDirection.ltr,
            children: <TestSemantics>[
              TestSemantics(
                children: <TestSemantics>[
                  TestSemantics(
                    flags: <SemanticsFlag>[SemanticsFlag.scopesRoute],
                    children: <TestSemantics>[
                      TestSemantics(
                        children: <TestSemantics>[
                          TestSemantics(
                            children: <TestSemantics>[
                              TestSemantics(
                                children: <TestSemantics>[
                                  TestSemantics(
                                    label: 'Leading',
                                    textDirection: TextDirection.ltr,
                                  ),
                                  TestSemantics(
                                    label: 'Action 1',
                                    textDirection: TextDirection.ltr,
                                  ),
                                ],
                              ),
                              TestSemantics(
                                children: <TestSemantics>[
                                  TestSemantics(
                                    flags: <SemanticsFlag>[SemanticsFlag.isHeader],
                                    label: 'Flexible space',
                                    textDirection: TextDirection.ltr,
                                  ),
                                ],
                              ),
                            ],
                          ),
                          TestSemantics(
                            flags: <SemanticsFlag>[SemanticsFlag.hasImplicitScrolling],
                          ),
                        ],
                      ),
                    ],
                  ),
                ],
              ),
            ],
          ),
        ],
      ),
      ignoreRect: true,
      ignoreTransform: true,
      ignoreId: true,
    ));

    semantics.dispose();
  });

  testWidgets('AppBar draws a light system bar for a dark background', (WidgetTester tester) async {
    final ThemeData darkTheme = ThemeData.dark();
    await tester.pumpWidget(MaterialApp(
      theme: darkTheme,
      home: Scaffold(
        appBar: AppBar(
          title: const Text('test'),
        ),
      ),
    ));

    expect(darkTheme.primaryColorBrightness, Brightness.dark);
    expect(darkTheme.colorScheme.brightness, Brightness.dark);
    expect(SystemChrome.latestStyle, const SystemUiOverlayStyle(
      statusBarBrightness: Brightness.dark,
      statusBarIconBrightness: Brightness.light,
    ));
  });

  testWidgets('AppBar draws a dark system bar for a light background', (WidgetTester tester) async {
    final ThemeData lightTheme = ThemeData(primarySwatch: Colors.lightBlue);
    await tester.pumpWidget(
      MaterialApp(
        theme: lightTheme,
        home: Scaffold(
          appBar: AppBar(
            title: const Text('test'),
          ),
        ),
      ),
    );

    expect(lightTheme.primaryColorBrightness, Brightness.light);
    expect(lightTheme.colorScheme.brightness, Brightness.light);
    expect(SystemChrome.latestStyle, const SystemUiOverlayStyle(
      statusBarBrightness: Brightness.light,
      statusBarIconBrightness: Brightness.dark,
    ));
  });

  testWidgets('Default system bar brightness based on AppBar background color brightness.', (WidgetTester tester) async {
    Widget buildAppBar(ThemeData theme) {
      return MaterialApp(
        theme: theme,
        home: Scaffold(
          appBar: AppBar(title: const Text('Title')),
        ),
      );
    }

    // Using a light theme.
    {
      await tester.pumpWidget(buildAppBar(ThemeData.from(colorScheme: const ColorScheme.light())));
      final Material appBarMaterial = tester.widget<Material>(
        find.descendant(
          of: find.byType(AppBar),
          matching: find.byType(Material),
        ),
      );
      final Brightness appBarBrightness = ThemeData.estimateBrightnessForColor(appBarMaterial.color!);
      final Brightness onAppBarBrightness = appBarBrightness == Brightness.light
        ? Brightness.dark
        : Brightness.light;

      expect(SystemChrome.latestStyle, SystemUiOverlayStyle(
        statusBarBrightness: appBarBrightness,
        statusBarIconBrightness: onAppBarBrightness,
      ));
    }

    // Using a dark theme.
    {
      await tester.pumpWidget(buildAppBar(ThemeData.from(colorScheme: const ColorScheme.dark())));
      final Material appBarMaterial = tester.widget<Material>(
        find.descendant(
          of: find.byType(AppBar),
          matching: find.byType(Material),
        ),
      );
      final Brightness appBarBrightness = ThemeData.estimateBrightnessForColor(appBarMaterial.color!);
      final Brightness onAppBarBrightness = appBarBrightness == Brightness.light
          ? Brightness.dark
          : Brightness.light;

      expect(SystemChrome.latestStyle, SystemUiOverlayStyle(
        statusBarBrightness: appBarBrightness,
        statusBarIconBrightness: onAppBarBrightness,
      ));
    }
  });

  testWidgets('Default status bar color', (WidgetTester tester) async {
    Future<void> pumpBoilerplate({required bool useMaterial3, required bool backwardsCompatibility}) async {
      await tester.pumpWidget(
        MaterialApp(
          key: GlobalKey(),
          theme: ThemeData.light().copyWith(
            useMaterial3: useMaterial3,
            appBarTheme: AppBarTheme(
              backwardsCompatibility: backwardsCompatibility,
            ),
          ),
          home: Scaffold(
            appBar: AppBar(
              title: const Text('title'),
            ),
          ),
        ),
      );
    }

    await pumpBoilerplate(useMaterial3: false, backwardsCompatibility: false);
    expect(SystemChrome.latestStyle!.statusBarColor, null);
    await pumpBoilerplate(useMaterial3: false, backwardsCompatibility: true);
    expect(SystemChrome.latestStyle!.statusBarColor, null);
    await pumpBoilerplate(useMaterial3: true, backwardsCompatibility: false);
    expect(SystemChrome.latestStyle!.statusBarColor, Colors.transparent);
    await pumpBoilerplate(useMaterial3: true, backwardsCompatibility: true);
    expect(SystemChrome.latestStyle!.statusBarColor, null);
  });

  testWidgets('AppBar systemOverlayStyle is use to style status bar and navigation bar', (WidgetTester tester) async {
    final SystemUiOverlayStyle systemOverlayStyle = SystemUiOverlayStyle.light.copyWith(
      statusBarColor: Colors.red,
      systemNavigationBarColor: Colors.green,
    );
    await tester.pumpWidget(
      MaterialApp(
        home: Scaffold(
          appBar: AppBar(
            title: const Text('test'),
            systemOverlayStyle: systemOverlayStyle,
          ),
        ),
      ),
    );

    expect(SystemChrome.latestStyle!.statusBarColor, Colors.red);
    expect(SystemChrome.latestStyle!.systemNavigationBarColor, Colors.green);
  });

  testWidgets('Changing SliverAppBar snap from true to false', (WidgetTester tester) async {
    // Regression test for https://github.com/flutter/flutter/issues/17598
    const double appBarHeight = 256.0;
    bool snap = true;

    await tester.pumpWidget(
      MaterialApp(
        home: StatefulBuilder(
          builder: (BuildContext context, StateSetter setState) {
            return Scaffold(
              body: CustomScrollView(
                slivers: <Widget>[
                  SliverAppBar(
                    expandedHeight: appBarHeight,
                    floating: true,
                    snap: snap,
                    actions: <Widget>[
                      TextButton(
                        child: const Text('snap=false'),
                        onPressed: () {
                          setState(() {
                            snap = false;
                          });
                        },
                      ),
                    ],
                    flexibleSpace: FlexibleSpaceBar(
                      background: Container(
                        height: appBarHeight,
                        color: Colors.orange,
                      ),
                    ),
                  ),
                  SliverList(
                    delegate: SliverChildListDelegate(
                      <Widget>[
                        Container(height: 1200.0, color: Colors.teal),
                      ],
                    ),
                  ),
                ],
              ),
            );
          },
        ),
      ),
    );

    TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
    await gesture.moveBy(const Offset(0.0, -100.0));
    await gesture.up();

    await tester.tap(find.text('snap=false'));
    await tester.pumpAndSettle();

    gesture = await tester.startGesture(const Offset(50.0, 400.0));
    await gesture.moveBy(const Offset(0.0, -100.0));
    await gesture.up();
    await tester.pump();
  });

  testWidgets('AppBar shape default', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        home: AppBar(
          leading: const Text('L'),
          title: const Text('No Scaffold'),
          actions: const <Widget>[Text('A1'), Text('A2')],
        ),
      ),
    );

    final Finder appBarFinder = find.byType(AppBar);
    AppBar getAppBarWidget(Finder finder) => tester.widget<AppBar>(finder);
    expect(getAppBarWidget(appBarFinder).shape, null);

    final Finder materialFinder = find.byType(Material);
    Material getMaterialWidget(Finder finder) => tester.widget<Material>(finder);
    expect(getMaterialWidget(materialFinder).shape, null);
  });

  testWidgets('AppBar with shape', (WidgetTester tester) async {
    const RoundedRectangleBorder roundedRectangleBorder = RoundedRectangleBorder(
      borderRadius: BorderRadius.all(Radius.circular(15.0)),
    );
    await tester.pumpWidget(
      MaterialApp(
        home: AppBar(
          leading: const Text('L'),
          title: const Text('No Scaffold'),
          actions: const <Widget>[Text('A1'), Text('A2')],
          shape: roundedRectangleBorder,
        ),
      ),
    );

    final Finder appBarFinder = find.byType(AppBar);
    AppBar getAppBarWidget(Finder finder) => tester.widget<AppBar>(finder);
    expect(getAppBarWidget(appBarFinder).shape, roundedRectangleBorder);

    final Finder materialFinder = find.byType(Material);
    Material getMaterialWidget(Finder finder) => tester.widget<Material>(finder);
    expect(getMaterialWidget(materialFinder).shape, roundedRectangleBorder);
  });

  testWidgets('SliverAppBar shape default', (WidgetTester tester) async {
    await tester.pumpWidget(
      const MaterialApp(
        home: CustomScrollView(
          slivers: <Widget>[
            SliverAppBar(
              leading: Text('L'),
              title: Text('No Scaffold'),
              actions: <Widget>[Text('A1'), Text('A2')],
            ),
          ],
        ),
      ),
    );

    final Finder sliverAppBarFinder = find.byType(SliverAppBar);
    SliverAppBar getSliverAppBarWidget(Finder finder) => tester.widget<SliverAppBar>(finder);
    expect(getSliverAppBarWidget(sliverAppBarFinder).shape, null);

    final Finder materialFinder = find.byType(Material);
    Material getMaterialWidget(Finder finder) => tester.widget<Material>(finder);
    expect(getMaterialWidget(materialFinder).shape, null);
  });

  testWidgets('SliverAppBar with shape', (WidgetTester tester) async {
    const RoundedRectangleBorder roundedRectangleBorder = RoundedRectangleBorder(
      borderRadius: BorderRadius.all(Radius.circular(15.0)),
    );
    await tester.pumpWidget(
      const MaterialApp(
        home: CustomScrollView(
          slivers: <Widget>[
            SliverAppBar(
              leading: Text('L'),
              title: Text('No Scaffold'),
              actions: <Widget>[Text('A1'), Text('A2')],
              shape: roundedRectangleBorder,
            ),
          ],
        ),
      ),
    );

    final Finder sliverAppBarFinder = find.byType(SliverAppBar);
    SliverAppBar getSliverAppBarWidget(Finder finder) => tester.widget<SliverAppBar>(finder);
    expect(getSliverAppBarWidget(sliverAppBarFinder).shape, roundedRectangleBorder);

    final Finder materialFinder = find.byType(Material);
    Material getMaterialWidget(Finder finder) => tester.widget<Material>(finder);
    expect(getMaterialWidget(materialFinder).shape, roundedRectangleBorder);
  });

  testWidgets('AppBars title has upper limit on text scaling, textScaleFactor = 1, 1.34, 2', (WidgetTester tester) async {
    late double textScaleFactor;

    Widget buildFrame() {
      return MaterialApp(
        // Test designed against 2014 font sizes.
        theme: ThemeData(textTheme: Typography.englishLike2014),
        home: Builder(
          builder: (BuildContext context) {
            return MediaQuery(
              data: MediaQuery.of(context).copyWith(textScaleFactor: textScaleFactor),
              child: Scaffold(
                appBar: AppBar(
                  centerTitle: false,
                  title: const Text('Jumbo', style: TextStyle(fontSize: 18)),
                ),
              ),
            );
          },
        ),
      );
    }

    final Finder appBarTitle = find.text('Jumbo');

    textScaleFactor = 1;
    await tester.pumpWidget(buildFrame());
    expect(tester.getRect(appBarTitle).height, 18);

    textScaleFactor = 1.34;
    await tester.pumpWidget(buildFrame());
    expect(tester.getRect(appBarTitle).height, 24);

    textScaleFactor = 2;
    await tester.pumpWidget(buildFrame());
    expect(tester.getRect(appBarTitle).height, 24);
  });

  testWidgets('AppBars with jumbo titles, textScaleFactor = 3, 3.5, 4', (WidgetTester tester) async {
    double textScaleFactor = 1.0;
    TextDirection textDirection = TextDirection.ltr;
    bool centerTitle = false;

    Widget buildFrame() {
      return MaterialApp(
        // Test designed against 2014 font sizes.
        theme: ThemeData(textTheme: Typography.englishLike2014),
        home: Builder(
          builder: (BuildContext context) {
            return Directionality(
              textDirection: textDirection,
              child: Builder(
                builder: (BuildContext context) {
                  return Scaffold(
                    appBar: AppBar(
                      centerTitle: centerTitle,
                      title: MediaQuery(
                        data: MediaQuery.of(context).copyWith(textScaleFactor: textScaleFactor),
                        child: const Text('Jumbo'),
                      ),
                    ),
                  );
                },
              ),
            );
          },
        ),
      );
    }

    final Finder appBarTitle = find.text('Jumbo');
    final Finder toolbar = find.byType(NavigationToolbar);

    // Overall screen size is 800x600
    // Left or right justified title is padded by 16 on the "start" side.
    // Toolbar height is 56.
    // "Jumbo" title is 100x20.

    await tester.pumpWidget(buildFrame());
    expect(tester.getRect(appBarTitle), const Rect.fromLTRB(16, 18, 116, 38));
    expect(tester.getCenter(appBarTitle).dy, tester.getCenter(toolbar).dy);

    textScaleFactor = 3; // "Jumbo" title is 300x60.
    await tester.pumpWidget(buildFrame());
    expect(tester.getRect(appBarTitle), const Rect.fromLTRB(16, -2, 316, 58));
    expect(tester.getCenter(appBarTitle).dy, tester.getCenter(toolbar).dy);

    textScaleFactor = 3.5; // "Jumbo" title is 350x70.
    await tester.pumpWidget(buildFrame());
    expect(tester.getRect(appBarTitle), const Rect.fromLTRB(16, -7, 366, 63));
    expect(tester.getCenter(appBarTitle).dy, tester.getCenter(toolbar).dy);

    textScaleFactor = 4; // "Jumbo" title is 400x80.
    await tester.pumpWidget(buildFrame());
    expect(tester.getRect(appBarTitle), const Rect.fromLTRB(16, -12, 416, 68));
    expect(tester.getCenter(appBarTitle).dy, tester.getCenter(toolbar).dy);

    textDirection = TextDirection.rtl; // Changed to rtl. "Jumbo" title is still 400x80.
    await tester.pumpWidget(buildFrame());
    expect(tester.getRect(appBarTitle), const Rect.fromLTRB(800.0 - 400.0 - 16.0, -12, 800.0 - 16.0, 68));
    expect(tester.getCenter(appBarTitle).dy, tester.getCenter(toolbar).dy);

    centerTitle = true; // Changed to true. "Jumbo" title is still 400x80.
    await tester.pumpWidget(buildFrame());
    expect(tester.getRect(appBarTitle), const Rect.fromLTRB(200, -12, 800.0 - 200.0, 68));
    expect(tester.getCenter(appBarTitle).dy, tester.getCenter(toolbar).dy);
  });

  testWidgets('SliverAppBar configures the delegate properly', (WidgetTester tester) async {
    Future<void> buildAndVerifyDelegate({ required bool pinned, required bool floating, required bool snap }) async {
      await tester.pumpWidget(
        MaterialApp(
          home: CustomScrollView(
            slivers: <Widget>[
              SliverAppBar(
                title: const Text('Jumbo'),
                pinned: pinned,
                floating: floating,
                snap: snap,
              ),
            ],
          ),
        ),
      );

      final SliverPersistentHeaderDelegate delegate = tester
        .widget<SliverPersistentHeader>(find.byType(SliverPersistentHeader))
        .delegate;

      // Ensure we have a non-null vsync when it's needed.
      if (!floating || (delegate.snapConfiguration == null && delegate.showOnScreenConfiguration == null)) {
        expect(delegate.vsync, isNotNull);
      }

      expect(delegate.showOnScreenConfiguration != null, snap && floating);
    }

    await buildAndVerifyDelegate(pinned: false, floating: true, snap: false);
    await buildAndVerifyDelegate(pinned: false, floating: true, snap: true);

    await buildAndVerifyDelegate(pinned: true, floating: true, snap: false);
    await buildAndVerifyDelegate(pinned: true, floating: true, snap: true);
  });

  testWidgets('AppBar respects toolbarHeight', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        home: Scaffold(
          appBar: AppBar(
            title: const Text('Title'),
            toolbarHeight: 48,
          ),
          body: Container(),
        ),
      ),
    );

    expect(appBarHeight(tester), 48);
  });

  testWidgets('SliverAppBar default collapsedHeight with respect to toolbarHeight', (WidgetTester tester) async {
    const double toolbarHeight = 100.0;

    await tester.pumpWidget(buildSliverAppBarApp(
      toolbarHeight: toolbarHeight,
    ));

    final ScrollController controller = primaryScrollController(tester);
    final double initialTabBarHeight = tabBarHeight(tester);

    // Scroll the not-pinned appbar out of view, to its collapsed height.
    controller.jumpTo(300.0);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsNothing);
    // By default, the collapsedHeight is toolbarHeight + bottom.preferredSize.height,
    // in this case initialTabBarHeight.
    expect(appBarHeight(tester), toolbarHeight + initialTabBarHeight);
  });

  testWidgets('SliverAppBar collapsedHeight with toolbarHeight', (WidgetTester tester) async {
    const double toolbarHeight = 100.0;
    const double collapsedHeight = 150.0;

    await tester.pumpWidget(buildSliverAppBarApp(
      toolbarHeight: toolbarHeight,
      collapsedHeight: collapsedHeight,
    ));

    final ScrollController controller = primaryScrollController(tester);
    final double initialTabBarHeight = tabBarHeight(tester);

    // Scroll the not-pinned appbar out of view, to its collapsed height.
    controller.jumpTo(300.0);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsNothing);
    expect(appBarHeight(tester), collapsedHeight + initialTabBarHeight);
  });

  testWidgets('SliverAppBar collapsedHeight', (WidgetTester tester) async {
    const double collapsedHeight = 56.0;

    await tester.pumpWidget(buildSliverAppBarApp(
      collapsedHeight: collapsedHeight,
    ));

    final ScrollController controller = primaryScrollController(tester);
    final double initialTabBarHeight = tabBarHeight(tester);

    // Scroll the not-pinned appbar out of view, to its collapsed height.
    controller.jumpTo(300.0);
    await tester.pump();
    expect(find.byType(SliverAppBar), findsNothing);
    expect(appBarHeight(tester), collapsedHeight + initialTabBarHeight);
  });

  testWidgets('AppBar respects leadingWidth', (WidgetTester tester) async {
    const Key key = Key('leading');
    await tester.pumpWidget(MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          leading: const Placeholder(key: key),
          leadingWidth: 100,
          title: const Text('Title'),
        ),
      ),
    ));

    // By default toolbarHeight is 56.0.
    expect(tester.getRect(find.byKey(key)), const Rect.fromLTRB(0, 0, 100, 56));
  });

  testWidgets('SliverAppBar respects leadingWidth', (WidgetTester tester) async {
    const Key key = Key('leading');
    await tester.pumpWidget(const MaterialApp(
      home: CustomScrollView(
        slivers: <Widget>[
          SliverAppBar(
            leading: Placeholder(key: key),
            leadingWidth: 100,
            title: Text('Title'),
          ),
        ],
      ),
    ));

    // By default toolbarHeight is 56.0.
    expect(tester.getRect(find.byKey(key)), const Rect.fromLTRB(0, 0, 100, 56));
  });

  testWidgets("AppBar with EndDrawer doesn't have leading", (WidgetTester tester) async {
    await tester.pumpWidget(MaterialApp(
      home: Scaffold(
        appBar: AppBar(),
        endDrawer: const Drawer(),
      ),
    ));

    final Finder endDrawerFinder = find.byTooltip('Open navigation menu');
    await tester.tap(endDrawerFinder);
    await tester.pump();

    final Finder appBarFinder = find.byType(NavigationToolbar);
    NavigationToolbar getAppBarWidget(Finder finder) => tester.widget<NavigationToolbar>(finder);
    expect(getAppBarWidget(appBarFinder).leading, null);
  });

  testWidgets('AppBar.titleSpacing defaults to NavigationToolbar.kMiddleSpacing', (WidgetTester tester) async {
    await tester.pumpWidget(MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Title'),
        ),
      ),
    ));

    final NavigationToolbar navToolBar = tester.widget(find.byType(NavigationToolbar));
    expect(navToolBar.middleSpacing, NavigationToolbar.kMiddleSpacing);
  });

  testWidgets('SliverAppBar.titleSpacing defaults to NavigationToolbar.kMiddleSpacing', (WidgetTester tester) async {
    await tester.pumpWidget(buildSliverAppBarApp());

    final NavigationToolbar navToolBar = tester.widget(find.byType(NavigationToolbar));
    expect(navToolBar.middleSpacing, NavigationToolbar.kMiddleSpacing);
  });

  testWidgets('AppBar foregroundColor and backgroundColor', (WidgetTester tester) async {
    const Color foregroundColor = Color(0xff00ff00);
    const Color backgroundColor = Color(0xff00ffff);
    final Key leadingIconKey = UniqueKey();
    final Key actionIconKey = UniqueKey();

    await tester.pumpWidget(
      MaterialApp(
        home: Scaffold(
          appBar: AppBar(
            foregroundColor: foregroundColor,
            backgroundColor: backgroundColor,
            leading: Icon(Icons.add_circle, key: leadingIconKey),
            title: const Text('title'),
            actions: <Widget>[Icon(Icons.ac_unit, key: actionIconKey), const Text('action')],
          ),
        ),
      ),
    );

    final Material appBarMaterial = tester.widget<Material>(
      find.descendant(
        of: find.byType(AppBar),
        matching: find.byType(Material),
      ),
    );
    expect(appBarMaterial.color, backgroundColor);

    final TextStyle titleTextStyle = tester.widget<DefaultTextStyle>(
      find.ancestor(of: find.text('title'), matching: find.byType(DefaultTextStyle)).first,
    ).style;
    expect(titleTextStyle.color, foregroundColor);

    final IconThemeData leadingIconTheme = tester.widget<IconTheme>(
      find.ancestor(of: find.byKey(leadingIconKey), matching: find.byType(IconTheme)).first,
    ).data;
    expect(leadingIconTheme.color, foregroundColor);

    final IconThemeData actionIconTheme = tester.widget<IconTheme>(
      find.ancestor(of: find.byKey(actionIconKey), matching: find.byType(IconTheme)).first,
    ).data;
    expect(actionIconTheme.color, foregroundColor);

    // Test icon color
    Color? leadingIconColor() => iconStyle(tester, Icons.add_circle)?.color;
    Color? actionIconColor() => iconStyle(tester, Icons.ac_unit)?.color;

    expect(leadingIconColor(), foregroundColor);
    expect(actionIconColor(), foregroundColor);
  });

  testWidgets('Leading, title, and actions show correct default colors', (WidgetTester tester) async {
    final ThemeData themeData = ThemeData.from(
      colorScheme: const ColorScheme.light(
        onPrimary: Colors.blue,
        onSurface: Colors.red,
        onSurfaceVariant: Colors.yellow),
    );
    final bool material3 = themeData.useMaterial3;
    await tester.pumpWidget(
      MaterialApp(
        theme: themeData,
        home: Scaffold(
          appBar: AppBar(
            leading: const Icon(Icons.add_circle),
            title: const Text('title'),
            actions: const <Widget>[
              Icon(Icons.ac_unit)
            ],
          ),
        ),
      ),
    );

    Color textColor() {
      return tester.renderObject<RenderParagraph>(find.text('title')).text.style!.color!;
    }
    Color? leadingIconColor() => iconStyle(tester, Icons.add_circle)?.color;
    Color? actionIconColor() => iconStyle(tester, Icons.ac_unit)?.color;

    // M2 default color are onPrimary, and M3 has onSurface for leading and title,
    // onSurfaceVariant for actions.
    expect(textColor(), material3 ? Colors.red : Colors.blue);
    expect(leadingIconColor(), material3 ? Colors.red : Colors.blue);
    expect(actionIconColor(), material3 ? Colors.yellow : Colors.blue);
  });

  // Regression test for https://github.com/flutter/flutter/issues/107305
  group('Icons are colored correctly by IconTheme and ActionIconTheme in M3', () {
    testWidgets('Icons and IconButtons are colored by IconTheme in M3', (WidgetTester tester) async {
      const Color iconColor = Color(0xff00ff00);
      final Key leadingIconKey = UniqueKey();
      final Key actionIconKey = UniqueKey();

      await tester.pumpWidget(
        MaterialApp(
          theme: ThemeData.from(
              colorScheme: const ColorScheme.light(), useMaterial3: true),
          home: Scaffold(
            appBar: AppBar(
              iconTheme: const IconThemeData(color: iconColor),
              leading: Icon(Icons.add_circle, key: leadingIconKey),
              title: const Text('title'),
              actions: <Widget>[
                Icon(Icons.ac_unit, key: actionIconKey),
                IconButton(icon: const Icon(Icons.add), onPressed: () {},)
              ],
            ),
          ),
        ),
      );

      Color? leadingIconColor() => iconStyle(tester, Icons.add_circle)?.color;
      Color? actionIconColor() => iconStyle(tester, Icons.ac_unit)?.color;
      Color? actionIconButtonColor() => iconStyle(tester, Icons.add)?.color;

      expect(leadingIconColor(), iconColor);
      expect(actionIconColor(), iconColor);
      expect(actionIconButtonColor(), iconColor);
    });

    testWidgets('Action icons and IconButtons are colored by ActionIconTheme - M3', (WidgetTester tester) async {
      final ThemeData themeData = ThemeData.from(
        colorScheme: const ColorScheme.light(),
        useMaterial3: true,
      );

      const Color actionsIconColor = Color(0xff0000ff);
      final Key leadingIconKey = UniqueKey();
      final Key actionIconKey = UniqueKey();

      await tester.pumpWidget(
        MaterialApp(
          theme: themeData,
          home: Scaffold(
            appBar: AppBar(
              actionsIconTheme: const IconThemeData(color: actionsIconColor),
              leading: Icon(Icons.add_circle, key: leadingIconKey),
              title: const Text('title'),
              actions: <Widget>[
                Icon(Icons.ac_unit, key: actionIconKey),
                IconButton(icon: const Icon(Icons.add), onPressed: () {}),
              ],
            ),
          ),
        ),
      );

      Color? leadingIconColor() => iconStyle(tester, Icons.add_circle)?.color;
      Color? actionIconColor() => iconStyle(tester, Icons.ac_unit)?.color;
      Color? actionIconButtonColor() => iconStyle(tester, Icons.add)?.color;

      expect(leadingIconColor(), themeData.colorScheme.onSurface);
      expect(actionIconColor(), actionsIconColor);
      expect(actionIconButtonColor(), actionsIconColor);
    });

    testWidgets('The actionIconTheme property overrides iconTheme - M3', (WidgetTester tester) async {
      final ThemeData themeData = ThemeData.from(
        colorScheme: const ColorScheme.light(),
        useMaterial3: true,
      );

      const Color overallIconColor = Color(0xff00ff00);
      const Color actionsIconColor = Color(0xff0000ff);
      final Key leadingIconKey = UniqueKey();
      final Key actionIconKey = UniqueKey();

      await tester.pumpWidget(
        MaterialApp(
          theme: themeData,
          home: Scaffold(
            appBar: AppBar(
              iconTheme: const IconThemeData(color: overallIconColor),
              actionsIconTheme: const IconThemeData(color: actionsIconColor),
              leading: Icon(Icons.add_circle, key: leadingIconKey),
              title: const Text('title'),
              actions: <Widget>[
                Icon(Icons.ac_unit, key: actionIconKey),
                IconButton(icon: const Icon(Icons.add), onPressed: () {}),
              ],
            ),
          ),
        ),
      );

      Color? leadingIconColor() => iconStyle(tester, Icons.add_circle)?.color;
      Color? actionIconColor() => iconStyle(tester, Icons.ac_unit)?.color;
      Color? actionIconButtonColor() => iconStyle(tester, Icons.add)?.color;

      expect(leadingIconColor(), overallIconColor);
      expect(actionIconColor(), actionsIconColor);
      expect(actionIconButtonColor(), actionsIconColor);
    });

    testWidgets('AppBar.iconTheme should override any IconButtonTheme present in the theme - M3', (WidgetTester tester) async {
      final ThemeData themeData = ThemeData(
        iconButtonTheme: IconButtonThemeData(
          style: IconButton.styleFrom(
            foregroundColor: Colors.red,
            iconSize: 32.0,
          ),
        ),
        useMaterial3: true,
      );

      const IconThemeData overallIconTheme = IconThemeData(color: Colors.yellow, size: 30.0);
      await tester.pumpWidget(
        MaterialApp(
          theme: themeData,
          home: Scaffold(
            appBar: AppBar(
              iconTheme: overallIconTheme,
              leading: IconButton(icon: const Icon(Icons.menu), onPressed: () {}),
              title: const Text('title'),
              actions: <Widget>[
                IconButton(icon: const Icon(Icons.add), onPressed: () {}),
              ],
            ),
          ),
        ),
      );

      Color? leadingIconButtonColor() => iconStyle(tester, Icons.menu)?.color;
      double? leadingIconButtonSize() => iconStyle(tester, Icons.menu)?.fontSize;
      Color? actionIconButtonColor() => iconStyle(tester, Icons.add)?.color;
      double? actionIconButtonSize() => iconStyle(tester, Icons.menu)?.fontSize;

      expect(leadingIconButtonColor(), Colors.yellow);
      expect(leadingIconButtonSize(), 30.0);
      expect(actionIconButtonColor(), Colors.yellow);
      expect(actionIconButtonSize(), 30.0);
    });

    testWidgets('AppBar.iconTheme should override any IconButtonTheme present in the theme for widgets containing an iconButton - M3', (WidgetTester tester) async {
      final ThemeData themeData = ThemeData(
        iconButtonTheme: IconButtonThemeData(
          style: IconButton.styleFrom(
            foregroundColor: Colors.red,
            iconSize: 32.0,
          ),
        ),
        useMaterial3: true,
      );

      const IconThemeData overallIconTheme = IconThemeData(color: Colors.yellow, size: 30.0);
      await tester.pumpWidget(
        MaterialApp(
          theme: themeData,
          home: Scaffold(
            appBar: AppBar(
              iconTheme: overallIconTheme,
              leading: BackButton(onPressed: () {}),
              title: const Text('title'),
            ),
          ),
        ),
      );

      Color? leadingIconButtonColor() => iconStyle(tester, Icons.arrow_back)?.color;
      double? leadingIconButtonSize() => iconStyle(tester, Icons.arrow_back)?.fontSize;

      expect(leadingIconButtonColor(), Colors.yellow);
      expect(leadingIconButtonSize(), 30.0);

    });

    testWidgets('AppBar.actionsIconTheme should override any IconButtonTheme present in the theme - M3', (WidgetTester tester) async {
      final ThemeData themeData = ThemeData(
        iconButtonTheme: IconButtonThemeData(
          style: IconButton.styleFrom(
            foregroundColor: Colors.red,
            iconSize: 32.0,
          ),
        ),
        useMaterial3: true,
      );

      const IconThemeData actionsIconTheme = IconThemeData(color: Colors.yellow, size: 30.0);
      await tester.pumpWidget(
        MaterialApp(
          theme: themeData,
          home: Scaffold(
            appBar: AppBar(
              actionsIconTheme: actionsIconTheme,
              title: const Text('title'),
              leading: IconButton(icon: const Icon(Icons.menu), onPressed: () {}),
              actions: <Widget>[
                IconButton(icon: const Icon(Icons.add), onPressed: () {}),
              ],
            ),
          ),
        ),
      );

      Color? leadingIconButtonColor() => iconStyle(tester, Icons.menu)?.color;
      double? leadingIconButtonSize() => iconStyle(tester, Icons.menu)?.fontSize;
      Color? actionIconButtonColor() => iconStyle(tester, Icons.add)?.color;
      double? actionIconButtonSize() => iconStyle(tester, Icons.add)?.fontSize;

      // The leading icon button uses the style in the IconButtonTheme because only actionsIconTheme is provided.
      expect(leadingIconButtonColor(), Colors.red);
      expect(leadingIconButtonSize(), 32.0);
      expect(actionIconButtonColor(), Colors.yellow);
      expect(actionIconButtonSize(), 30.0);
    });

    testWidgets('AppBar.actionsIconTheme should override any IconButtonTheme present in the theme for widgets containing an iconButton - M3', (WidgetTester tester) async {
      final ThemeData themeData = ThemeData(
        iconButtonTheme: IconButtonThemeData(
          style: IconButton.styleFrom(
            foregroundColor: Colors.red,
            iconSize: 32.0,
          ),
        ),
        useMaterial3: true,
      );

      const IconThemeData actionsIconTheme = IconThemeData(color: Colors.yellow, size: 30.0);
      await tester.pumpWidget(
        MaterialApp(
          theme: themeData,
          home: Scaffold(
            appBar: AppBar(
              actionsIconTheme: actionsIconTheme,
              title: const Text('title'),
              actions: <Widget>[
                BackButton(onPressed: () {}),
              ],
            ),
          ),
        ),
      );

      Color? actionIconButtonColor() => iconStyle(tester, Icons.arrow_back)?.color;
      double? actionIconButtonSize() => iconStyle(tester, Icons.arrow_back)?.fontSize;

      expect(actionIconButtonColor(), Colors.yellow);
      expect(actionIconButtonSize(), 30.0);
    });

    testWidgets('The foregroundColor property of the AppBar overrides any IconButtonTheme present in the theme - M3', (WidgetTester tester) async {
      final ThemeData themeData = ThemeData(
        iconButtonTheme: IconButtonThemeData(
          style: IconButton.styleFrom(
            foregroundColor: Colors.red,
          ),
        ),
        useMaterial3: true,
      );

      await tester.pumpWidget(
        MaterialApp(
          theme: themeData,
          home: Scaffold(
            appBar: AppBar(
              foregroundColor: Colors.purple,
              title: const Text('title'),
              leading: IconButton(icon: const Icon(Icons.menu), onPressed: () {}),
              actions: <Widget>[
                IconButton(icon: const Icon(Icons.add), onPressed: () {}),
              ],
            ),
          ),
        ),
      );

      Color? leadingIconButtonColor() => iconStyle(tester, Icons.menu)?.color;
      Color? actionIconButtonColor() => iconStyle(tester, Icons.add)?.color;

      expect(leadingIconButtonColor(), Colors.purple);
      expect(actionIconButtonColor(), Colors.purple);
    });
  });

  testWidgets('AppBarTheme.backwardsCompatibility', (WidgetTester tester) async {
    const Color foregroundColor = Color(0xff00ff00);
    final Key leadingIconKey = UniqueKey();
    final Key actionIconKey = UniqueKey();

    await tester.pumpWidget(
      MaterialApp(
        theme: ThemeData.light().copyWith(
          useMaterial3: false,
          appBarTheme: const AppBarTheme(
            backwardsCompatibility: false,
          ),
        ),
        home: Scaffold(
          appBar: AppBar(
            foregroundColor: foregroundColor, // only applies if backwardsCompatibility is false
            leading: Icon(Icons.add_circle, key: leadingIconKey),
            title: const Text('title'),
            actions: <Widget>[Icon(Icons.ac_unit, key: actionIconKey), const Text('action')],
          ),
        ),
      ),
    );

    final TextStyle titleTextStyle = tester.widget<DefaultTextStyle>(
      find.ancestor(of: find.text('title'), matching: find.byType(DefaultTextStyle)).first,
    ).style;
    expect(titleTextStyle.color, foregroundColor);

    final IconThemeData leadingIconTheme = tester.widget<IconTheme>(
      find.ancestor(of: find.byKey(leadingIconKey), matching: find.byType(IconTheme)).first,
    ).data;
    expect(leadingIconTheme.color, foregroundColor);

    final IconThemeData actionIconTheme = tester.widget<IconTheme>(
      find.ancestor(of: find.byKey(actionIconKey), matching: find.byType(IconTheme)).first,
    ).data;
    expect(actionIconTheme.color, foregroundColor);

    // Test icon color
    Color? leadingIconColor() => iconStyle(tester, Icons.add_circle)?.color;
    Color? actionIconColor() => iconStyle(tester, Icons.ac_unit)?.color;

    expect(leadingIconColor(), foregroundColor);
    expect(actionIconColor(), foregroundColor);
  });

  group('MaterialStateColor scrolledUnder', () {
    const double collapsedHeight = kToolbarHeight;
    const double expandedHeight = 200.0;
    const Color scrolledColor = Color(0xff00ff00);
    const Color defaultColor = Color(0xff0000ff);

    Finder findAppBarMaterial() {
      return find.descendant(of: find.byType(AppBar), matching: find.byType(Material)).first;
    }

    Color? getAppBarBackgroundColor(WidgetTester tester) {
      return tester.widget<Material>(findAppBarMaterial()).color;
    }

    group('SliverAppBar', () {
      Widget buildSliverApp({
        required double contentHeight,
        bool reverse = false,
        bool includeFlexibleSpace = false,
      }) {
        return MaterialApp(
          home: Scaffold(
            body: CustomScrollView(
              reverse: reverse,
              slivers: <Widget>[
                SliverAppBar(
                  elevation: 0,
                  backgroundColor: MaterialStateColor.resolveWith((Set<MaterialState> states) {
                    return states.contains(MaterialState.scrolledUnder)
                      ? scrolledColor
                      : defaultColor;
                  }),
                  expandedHeight: expandedHeight,
                  pinned: true,
                  flexibleSpace: includeFlexibleSpace
                      ? const FlexibleSpaceBar(title: Text('SliverAppBar'))
                      : null,
                ),
                SliverList(
                  delegate: SliverChildListDelegate(
                    <Widget>[
                      Container(height: contentHeight, color: Colors.teal),
                    ],
                  ),
                ),
              ],
            ),
          ),
        );
      }

      testWidgets('backgroundColor', (WidgetTester tester) async {
        await tester.pumpWidget(
          buildSliverApp(contentHeight: 1200.0)
        );

        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, expandedHeight);

        TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
        await gesture.moveBy(const Offset(0.0, -expandedHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), scrolledColor);
        expect(tester.getSize(findAppBarMaterial()).height, collapsedHeight);

        gesture = await tester.startGesture(const Offset(50.0, 300.0));
        await gesture.moveBy(const Offset(0.0, expandedHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, expandedHeight);
      });

      testWidgets('backgroundColor with FlexibleSpace', (WidgetTester tester) async {
        await tester.pumpWidget(
          buildSliverApp(contentHeight: 1200.0, includeFlexibleSpace: true)
        );

        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, expandedHeight);

        TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
        await gesture.moveBy(const Offset(0.0, -expandedHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), scrolledColor);
        expect(tester.getSize(findAppBarMaterial()).height, collapsedHeight);

        gesture = await tester.startGesture(const Offset(50.0, 300.0));
        await gesture.moveBy(const Offset(0.0, expandedHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, expandedHeight);
      });

      testWidgets('backgroundColor - reverse', (WidgetTester tester) async {
        await tester.pumpWidget(
          buildSliverApp(contentHeight: 1200.0, reverse: true)
        );

        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, expandedHeight);

        TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
        await gesture.moveBy(const Offset(0.0, expandedHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), scrolledColor);
        expect(tester.getSize(findAppBarMaterial()).height, collapsedHeight);

        gesture = await tester.startGesture(const Offset(50.0, 300.0));
        await gesture.moveBy(const Offset(0.0, -expandedHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, expandedHeight);
      });

      testWidgets('backgroundColor with FlexibleSpace - reverse', (WidgetTester tester) async {
        await tester.pumpWidget(
          buildSliverApp(
            contentHeight: 1200.0,
            reverse: true,
            includeFlexibleSpace: true,
          )
        );

        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, expandedHeight);

        TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
        await gesture.moveBy(const Offset(0.0, expandedHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), scrolledColor);
        expect(tester.getSize(findAppBarMaterial()).height, collapsedHeight);

        gesture = await tester.startGesture(const Offset(50.0, 300.0));
        await gesture.moveBy(const Offset(0.0, -expandedHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, expandedHeight);
      });

      testWidgets('backgroundColor - not triggered in reverse for short content', (WidgetTester tester) async {
        await tester.pumpWidget(
          buildSliverApp(contentHeight: 200, reverse: true)
        );

        // In reverse, the content here is not long enough to scroll under the app
        // bar.
        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, expandedHeight);

        final TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
        await gesture.moveBy(const Offset(0.0, expandedHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, expandedHeight);
      });

      testWidgets('backgroundColor with FlexibleSpace - not triggered in reverse for short content', (WidgetTester tester) async {
        await tester.pumpWidget(
          buildSliverApp(
            contentHeight: 200,
            reverse: true,
            includeFlexibleSpace: true,
          )
        );

        // In reverse, the content here is not long enough to scroll under the app
        // bar.
        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, expandedHeight);

        final TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
        await gesture.moveBy(const Offset(0.0, expandedHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, expandedHeight);
      });
    });

    group('AppBar', () {
      Widget buildAppBar({
        required double contentHeight,
        bool reverse = false,
        bool includeFlexibleSpace = false
      }) {
        return MaterialApp(
          home: Scaffold(
            appBar: AppBar(
              elevation: 0,
              backgroundColor: MaterialStateColor.resolveWith((Set<MaterialState> states) {
                return states.contains(MaterialState.scrolledUnder)
                  ? scrolledColor
                  : defaultColor;
              }),
              title: const Text('AppBar'),
              flexibleSpace: includeFlexibleSpace
                ? const FlexibleSpaceBar(title: Text('FlexibleSpace'))
                : null,
            ),
            body: ListView(
              reverse: reverse,
              children: <Widget>[
                Container(height: contentHeight, color: Colors.teal),
              ],
            ),
          ),
        );
      }

      testWidgets('backgroundColor', (WidgetTester tester) async {
        await tester.pumpWidget(
          buildAppBar(contentHeight: 1200.0)
        );

        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);

        TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
        await gesture.moveBy(const Offset(0.0, -kToolbarHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), scrolledColor);
        expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);

        gesture = await tester.startGesture(const Offset(50.0, 300.0));
        await gesture.moveBy(const Offset(0.0, kToolbarHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);
      });

      testWidgets('backgroundColor with FlexibleSpace', (WidgetTester tester) async {
        await tester.pumpWidget(
          buildAppBar(contentHeight: 1200.0, includeFlexibleSpace: true)
        );

        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);

        TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
        await gesture.moveBy(const Offset(0.0, -kToolbarHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), scrolledColor);
        expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);

        gesture = await tester.startGesture(const Offset(50.0, 300.0));
        await gesture.moveBy(const Offset(0.0, kToolbarHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);
      });

      testWidgets('backgroundColor - reverse', (WidgetTester tester) async {
        await tester.pumpWidget(
          buildAppBar(contentHeight: 1200.0, reverse: true)
        );
        await tester.pump();

        // In this test case, the content always extends under the AppBar, so it
        // should always be the scrolledColor.
        expect(getAppBarBackgroundColor(tester), scrolledColor);
        expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);

        TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
        await gesture.moveBy(const Offset(0.0, kToolbarHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), scrolledColor);
        expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);

        gesture = await tester.startGesture(const Offset(50.0, 300.0));
        await gesture.moveBy(const Offset(0.0, -kToolbarHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), scrolledColor);
        expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);
      });

      testWidgets('backgroundColor with FlexibleSpace - reverse', (WidgetTester tester) async {
        await tester.pumpWidget(
          buildAppBar(
            contentHeight: 1200.0,
            reverse: true,
            includeFlexibleSpace: true,
          )
        );
        await tester.pump();

        // In this test case, the content always extends under the AppBar, so it
        // should always be the scrolledColor.
        expect(getAppBarBackgroundColor(tester), scrolledColor);
        expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);

        TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
        await gesture.moveBy(const Offset(0.0, kToolbarHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), scrolledColor);
        expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);

        gesture = await tester.startGesture(const Offset(50.0, 300.0));
        await gesture.moveBy(const Offset(0.0, -kToolbarHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), scrolledColor);
        expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);
      });

      testWidgets('_handleScrollNotification safely calls setState()', (WidgetTester tester) async {
        // Regression test for failures found in Google internal issue b/185192049.
        final ScrollController controller = ScrollController(initialScrollOffset: 400);
        await tester.pumpWidget(
          MaterialApp(
            home: Scaffold(
              appBar: AppBar(
                title: const Text('AppBar'),
              ),
              body: Scrollbar(
                isAlwaysShown: true,
                controller: controller,
                child: ListView(
                  controller: controller,
                  children: <Widget>[
                    Container(height: 1200.0, color: Colors.teal),
                  ],
                ),
              ),
            ),
          ),
        );

        expect(tester.takeException(), isNull);
      });

      testWidgets('does not trigger on horizontal scroll', (WidgetTester tester) async {
        await tester.pumpWidget(
          MaterialApp(
            home: Scaffold(
              appBar: AppBar(
                elevation: 0,
                backgroundColor: MaterialStateColor.resolveWith((Set<MaterialState> states) {
                  return states.contains(MaterialState.scrolledUnder)
                    ? scrolledColor
                    : defaultColor;
                }),
                title: const Text('AppBar'),
              ),
              body: ListView(
                scrollDirection: Axis.horizontal,
                children: <Widget>[
                  Container(height: 600.0, width: 1200.0, color: Colors.teal),
                ],
              ),
            ),
          ),
        );

        expect(getAppBarBackgroundColor(tester), defaultColor);

        TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
        await gesture.moveBy(const Offset(-100.0, 0.0));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), defaultColor);

        gesture = await tester.startGesture(const Offset(50.0, 400.0));
        await gesture.moveBy(const Offset(100.0, 0.0));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), defaultColor);
      });

      testWidgets('backgroundColor - not triggered in reverse for short content', (WidgetTester tester) async {
        await tester.pumpWidget(
          buildAppBar(
            contentHeight: 200.0,
            reverse: true,
          )
        );
        await tester.pump();

        // In reverse, the content here is not long enough to scroll under the app
        // bar.
        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);

        final TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
        await gesture.moveBy(const Offset(0.0, kToolbarHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);
      });

      testWidgets('backgroundColor with FlexibleSpace - not triggered in reverse for short content', (WidgetTester tester) async {
        await tester.pumpWidget(
          buildAppBar(
            contentHeight: 200.0,
            reverse: true,
            includeFlexibleSpace: true,
          )
        );
        await tester.pump();

        // In reverse, the content here is not long enough to scroll under the app
        // bar.
        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);

        final TestGesture gesture = await tester.startGesture(const Offset(50.0, 400.0));
        await gesture.moveBy(const Offset(0.0, kToolbarHeight));
        await gesture.up();
        await tester.pumpAndSettle();

        expect(getAppBarBackgroundColor(tester), defaultColor);
        expect(tester.getSize(findAppBarMaterial()).height, kToolbarHeight);
      });
    });
  });

  // Regression test for https://github.com/flutter/flutter/issues/80256
  testWidgets('The second page should have a back button even it has a end drawer', (WidgetTester tester) async {
    final Page<void> page1 = MaterialPage<void>(
        key: const ValueKey<String>('1'),
        child: Scaffold(
          key: const ValueKey<String>('1'),
          appBar: AppBar(),
          endDrawer: const Drawer(),
        )
    );
    final Page<void> page2 = MaterialPage<void>(
        key: const ValueKey<String>('2'),
        child: Scaffold(
          key: const ValueKey<String>('2'),
          appBar: AppBar(),
          endDrawer: const Drawer(),
        )
    );
    final List<Page<void>> pages = <Page<void>>[ page1, page2 ];
    await tester.pumpWidget(
      MaterialApp(
        home: Navigator(
          pages: pages,
          onPopPage: (Route<Object?> route, Object? result) => false,
        ),
      ),
    );

    // The page2 should have a back button.
    expect(
        find.descendant(
          of: find.byKey(const ValueKey<String>('2')),
          matching: find.byType(BackButton),
        ),
        findsOneWidget
    );
  });

  testWidgets('AppBar.preferredHeightFor', (WidgetTester tester) async {
    late double preferredHeight;
    late Size preferredSize;

    Widget buildFrame({ double? themeToolbarHeight, double? appBarToolbarHeight }) {
      final AppBar appBar = AppBar(
        toolbarHeight: appBarToolbarHeight,
      );
      return MaterialApp(
        theme: ThemeData.light().copyWith(
          appBarTheme: AppBarTheme(
            toolbarHeight: themeToolbarHeight,
          ),
        ),
        home: Builder(
          builder: (BuildContext context) {
            preferredHeight = AppBar.preferredHeightFor(context, appBar.preferredSize);
            preferredSize = appBar.preferredSize;
            return Scaffold(
              appBar: appBar,
              body: const Placeholder(),
            );
          },
        ),
      );
    }

    await tester.pumpWidget(buildFrame());
    expect(tester.getSize(find.byType(AppBar)).height, kToolbarHeight);
    expect(preferredHeight, kToolbarHeight);
    expect(preferredSize.height, kToolbarHeight);

    await tester.pumpWidget(buildFrame(themeToolbarHeight: 96));
    await tester.pumpAndSettle(); // Animate MaterialApp theme change.
    expect(tester.getSize(find.byType(AppBar)).height, 96);
    expect(preferredHeight, 96);
    // Special case: AppBarTheme.toolbarHeight specified,
    // AppBar.theme.toolbarHeight is null.
    expect(preferredSize.height, kToolbarHeight);

    await tester.pumpWidget(buildFrame(appBarToolbarHeight: 64));
    await tester.pumpAndSettle(); // Animate MaterialApp theme change.
    expect(tester.getSize(find.byType(AppBar)).height, 64);
    expect(preferredHeight, 64);
    expect(preferredSize.height, 64);

    await tester.pumpWidget(buildFrame(appBarToolbarHeight: 64, themeToolbarHeight: 96));
    await tester.pumpAndSettle(); // Animate MaterialApp theme change.
    expect(tester.getSize(find.byType(AppBar)).height, 64);
    expect(preferredHeight, 64);
    expect(preferredSize.height, 64);
  });

  testWidgets('AppBar title with actions should have the same position regardless of centerTitle', (WidgetTester tester) async {
    final Key titleKey = UniqueKey();
    bool centerTitle = false;

    Widget buildApp() {
      return MaterialApp(
        home: Scaffold(
          appBar: AppBar(
            centerTitle: centerTitle,
            title: Container(
              key: titleKey,
              constraints: BoxConstraints.loose(const Size(1000.0, 1000.0)),
            ),
            actions: const <Widget>[
              SizedBox(width: 48.0),
            ],
          ),
        ),
      );
    }

    await tester.pumpWidget(buildApp());
    final Finder title = find.byKey(titleKey);
    expect(tester.getTopLeft(title).dx, 16.0);

    centerTitle = true;
    await tester.pumpWidget(buildApp());
    expect(tester.getTopLeft(title).dx, 16.0);
  });

  testWidgets('AppBar leading widget can take up arbitrary space', (WidgetTester tester) async {
    final Key leadingKey = UniqueKey();
    final Key titleKey = UniqueKey();
    late double leadingWidth;

    Widget buildApp() {
      return MaterialApp(
        home: LayoutBuilder(
          builder: (BuildContext context, BoxConstraints constraints) {
            leadingWidth = constraints.maxWidth / 2;
            return Scaffold(
              appBar: AppBar(
                leading: Container(
                  key: leadingKey,
                  width: leadingWidth,
                ),
                leadingWidth: leadingWidth,
                title: Text('Title', key: titleKey),
              ),
            );
          }
        ),
      );
    }

    await tester.pumpWidget(buildApp());
    expect(tester.getTopLeft(find.byKey(titleKey)).dx, leadingWidth + 16.0);
    expect(tester.getSize(find.byKey(leadingKey)).width, leadingWidth);
  });

  group('AppBar.forceMaterialTransparency', () {
    Material getAppBarMaterial(WidgetTester tester) {
      return tester.widget<Material>(find
          .descendant(of: find.byType(AppBar), matching: find.byType(Material))
          .first);
    }

    // Generates a MaterialApp with an AppBar with a TextButton beneath it
    // (via extendBodyBehindAppBar = true).
    Widget buildWidget({
      required bool forceMaterialTransparency,
      required VoidCallback onPressed
    }) {
      return MaterialApp(
        home: Scaffold(
          extendBodyBehindAppBar: true,
          appBar: AppBar(
            forceMaterialTransparency: forceMaterialTransparency,
            elevation: 3,
            backgroundColor: Colors.red,
            title: const Text('AppBar'),
          ),
          body: Align(
            alignment: Alignment.topCenter,
            child: TextButton(
              onPressed: onPressed,
              child: const Text('press me'),
            ),
          ),
        ),
      );
    }

    testWidgets(
        'forceMaterialTransparency == true allows gestures beneath the app bar', (WidgetTester tester) async {
      bool buttonWasPressed = false;
      final Widget widget = buildWidget(
          forceMaterialTransparency:true,
          onPressed:() { buttonWasPressed = true; },
      );
      await tester.pumpWidget(widget);

      final Material material = getAppBarMaterial(tester);
      expect(material.type, MaterialType.transparency);

      final Finder buttonFinder = find.byType(TextButton);
      await tester.tap(buttonFinder);
      await tester.pump();
      expect(buttonWasPressed, isTrue);
    });

    testWidgets(
        'forceMaterialTransparency == false does not allow gestures beneath the app bar', (WidgetTester tester) async {
      // Set this, and tester.tap(warnIfMissed:false), to suppress
      // errors/warning that the button is not hittable (which is expected).
      WidgetController.hitTestWarningShouldBeFatal = false;

      bool buttonWasPressed = false;
      final Widget widget = buildWidget(
        forceMaterialTransparency:false,
        onPressed:() { buttonWasPressed = true; },
      );
      await tester.pumpWidget(widget);

      final Material material = getAppBarMaterial(tester);
      expect(material.type, MaterialType.canvas);

      final Finder buttonFinder = find.byType(TextButton);
      await tester.tap(buttonFinder, warnIfMissed:false);
      await tester.pump();
      expect(buttonWasPressed, isFalse);
    });
  });
}