packages/flutter/test/material/expansion_tile_test.dart - mirrors/flutter - Git at Google

 // 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_test/flutter_test.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter/material.dart';

 class TestIcon extends StatefulWidget {
   const TestIcon({Key? key}) : super(key: key);

   @override
   TestIconState createState() => TestIconState();
 }

 class TestIconState extends State<TestIcon> {
   late IconThemeData iconTheme;

   @override
   Widget build(BuildContext context) {
     iconTheme = IconTheme.of(context);
     return const Icon(Icons.expand_more);
   }
 }

 class TestText extends StatefulWidget {
   const TestText(this.text, {Key? key}) : super(key: key);

   final String text;

   @override
   TestTextState createState() => TestTextState();
 }

 class TestTextState extends State<TestText> {
   late TextStyle textStyle;

   @override
   Widget build(BuildContext context) {
     textStyle = DefaultTextStyle.of(context).style;
     return Text(widget.text);
   }
 }

 void main() {
   const Color _dividerColor = Color(0x1f333333);
   const Color _accentColor = Colors.blueAccent;
   const Color _unselectedWidgetColor = Colors.black54;
   const Color _headerColor = Colors.black45;

   testWidgets('ExpansionTile initial state', (WidgetTester tester) async {
     final Key topKey = UniqueKey();
     const Key expandedKey = PageStorageKey<String>('expanded');
     const Key collapsedKey = PageStorageKey<String>('collapsed');
     const Key defaultKey = PageStorageKey<String>('default');

     final Key tileKey = UniqueKey();

     await tester.pumpWidget(MaterialApp(
       theme: ThemeData(
         dividerColor: _dividerColor,
       ),
       home: Material(
         child: SingleChildScrollView(
           child: Column(
             children: <Widget>[
               ListTile(title: const Text('Top'), key: topKey),
               ExpansionTile(
                 key: expandedKey,
                 initiallyExpanded: true,
                 title: const Text('Expanded'),
                 backgroundColor: Colors.red,
                 children: <Widget>[
                   ListTile(
                     key: tileKey,
                     title: const Text('0'),
                   ),
                 ],
               ),
               ExpansionTile(
                 key: collapsedKey,
                 initiallyExpanded: false,
                 title: const Text('Collapsed'),
                 children: <Widget>[
                   ListTile(
                     key: tileKey,
                     title: const Text('0'),
                   ),
                 ],
               ),
               const ExpansionTile(
                 key: defaultKey,
                 title: Text('Default'),
                 children: <Widget>[
                   ListTile(title: Text('0')),
                 ],
               ),
             ],
           ),
         ),
       ),
     ));

     double getHeight(Key key) => tester.getSize(find.byKey(key)).height;
     Container getContainer(Key key) => tester.firstWidget(find.descendant(
       of: find.byKey(key),
       matching: find.byType(Container),
     ));

     expect(getHeight(topKey), getHeight(expandedKey) - getHeight(tileKey) - 2.0);
     expect(getHeight(topKey), getHeight(collapsedKey) - 2.0);
     expect(getHeight(topKey), getHeight(defaultKey) - 2.0);

     BoxDecoration expandedContainerDecoration = getContainer(expandedKey).decoration! as BoxDecoration;
     expect(expandedContainerDecoration.color, Colors.red);
     expect(expandedContainerDecoration.border!.top.color, _dividerColor);
     expect(expandedContainerDecoration.border!.bottom.color, _dividerColor);

     BoxDecoration collapsedContainerDecoration = getContainer(collapsedKey).decoration! as BoxDecoration;
     expect(collapsedContainerDecoration.color, Colors.transparent);
     expect(collapsedContainerDecoration.border!.top.color, Colors.transparent);
     expect(collapsedContainerDecoration.border!.bottom.color, Colors.transparent);

     await tester.tap(find.text('Expanded'));
     await tester.tap(find.text('Collapsed'));
     await tester.tap(find.text('Default'));

     await tester.pump();

     // Pump to the middle of the animation for expansion.
     await tester.pump(const Duration(milliseconds: 100));
     final BoxDecoration collapsingContainerDecoration = getContainer(collapsedKey).decoration! as BoxDecoration;
     expect(collapsingContainerDecoration.color, Colors.transparent);
     // Opacity should change but color component should remain the same.
     expect(collapsingContainerDecoration.border!.top.color, const Color(0x15333333));
     expect(collapsingContainerDecoration.border!.bottom.color, const Color(0x15333333));

     // Pump all the way to the end now.
     await tester.pump(const Duration(seconds: 1));

     expect(getHeight(topKey), getHeight(expandedKey) - 2.0);
     expect(getHeight(topKey), getHeight(collapsedKey) - getHeight(tileKey) - 2.0);
     expect(getHeight(topKey), getHeight(defaultKey) - getHeight(tileKey) - 2.0);

     // Expanded should be collapsed now.
     expandedContainerDecoration = getContainer(expandedKey).decoration! as BoxDecoration;
     expect(expandedContainerDecoration.color, Colors.transparent);
     expect(expandedContainerDecoration.border!.top.color, Colors.transparent);
     expect(expandedContainerDecoration.border!.bottom.color, Colors.transparent);

     // Collapsed should be expanded now.
     collapsedContainerDecoration = getContainer(collapsedKey).decoration! as BoxDecoration;
     expect(collapsedContainerDecoration.color, Colors.transparent);
     expect(collapsedContainerDecoration.border!.top.color, _dividerColor);
     expect(collapsedContainerDecoration.border!.bottom.color, _dividerColor);
   }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS,  TargetPlatform.macOS }));

   testWidgets('ListTileTheme', (WidgetTester tester) async {
     final Key expandedTitleKey = UniqueKey();
     final Key collapsedTitleKey = UniqueKey();
     final Key expandedIconKey = UniqueKey();
     final Key collapsedIconKey = UniqueKey();

     await tester.pumpWidget(
       MaterialApp(
         theme: ThemeData(
           accentColor: _accentColor,
           unselectedWidgetColor: _unselectedWidgetColor,
           textTheme: const TextTheme(subtitle1: TextStyle(color: _headerColor)),
         ),
         home: Material(
           child: SingleChildScrollView(
             child: Column(
               children: <Widget>[
                 const ListTile(title: Text('Top')),
                 ExpansionTile(
                   initiallyExpanded: true,
                   title: TestText('Expanded', key: expandedTitleKey),
                   backgroundColor: Colors.red,
                   children: const <Widget>[ListTile(title: Text('0'))],
                   trailing: TestIcon(key: expandedIconKey),
                 ),
                 ExpansionTile(
                   initiallyExpanded: false,
                   title: TestText('Collapsed', key: collapsedTitleKey),
                   children: const <Widget>[ListTile(title: Text('0'))],
                   trailing: TestIcon(key: collapsedIconKey),
                 ),
               ],
             ),
           ),
         ),
       ),
     );

     Color iconColor(Key key) => tester.state<TestIconState>(find.byKey(key)).iconTheme.color!;
     Color textColor(Key key) => tester.state<TestTextState>(find.byKey(key)).textStyle.color!;

     expect(textColor(expandedTitleKey), _accentColor);
     expect(textColor(collapsedTitleKey), _headerColor);
     expect(iconColor(expandedIconKey), _accentColor);
     expect(iconColor(collapsedIconKey), _unselectedWidgetColor);

     // Tap both tiles to change their state: collapse and extend respectively
     await tester.tap(find.text('Expanded'));
     await tester.tap(find.text('Collapsed'));
     await tester.pump();
     await tester.pump(const Duration(seconds: 1));
     await tester.pump(const Duration(seconds: 1));

     expect(textColor(expandedTitleKey), _headerColor);
     expect(textColor(collapsedTitleKey), _accentColor);
     expect(iconColor(expandedIconKey), _unselectedWidgetColor);
     expect(iconColor(collapsedIconKey), _accentColor);
   }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS,  TargetPlatform.macOS }));

   testWidgets('ExpansionTile subtitle', (WidgetTester tester) async {
     await tester.pumpWidget(
       const MaterialApp(
         home: Scaffold(
           body: ExpansionTile(
             title: Text('Title'),
             subtitle: Text('Subtitle'),
             children: <Widget>[ListTile(title: Text('0'))],
           ),
         ),
       ),
     );

     expect(find.text('Subtitle'), findsOneWidget);
   });

   testWidgets('ExpansionTile maintainState', (WidgetTester tester) async {
      await tester.pumpWidget(
        MaterialApp(
          theme: ThemeData(
            platform: TargetPlatform.iOS,
            dividerColor: _dividerColor,
          ),
          home: Material(
            child: SingleChildScrollView(
              child: Column(
                children: const <Widget>[
                  ExpansionTile(
                    title: Text('Tile 1'),
                    initiallyExpanded: false,
                    maintainState: true,
                    children: <Widget>[
                      Text('Maintaining State'),
                    ],
                  ),
                  ExpansionTile(
                    title: Text('Title 2'),
                    initiallyExpanded: false,
                    maintainState: false,
                    children: <Widget>[
                      Text('Discarding State'),
                    ],
                  ),
                ],
              ),
            ),
          ),
      ));

      // This text should be offstage while ExpansionTile collapsed
      expect(find.text('Maintaining State', skipOffstage: false), findsOneWidget);
      expect(find.text('Maintaining State'), findsNothing);
      // This text shouldn't be there while ExpansionTile collapsed
      expect(find.text('Discarding State'), findsNothing);
    });

   testWidgets('ExpansionTile padding test', (WidgetTester tester) async {
     await tester.pumpWidget(const MaterialApp(
       home: Material(
         child: Center(
           child: ExpansionTile(
             title: Text('Hello'),
             tilePadding: EdgeInsets.fromLTRB(8, 12, 4, 10),
           ),
         ),
       ),
     ));

     final Rect titleRect = tester.getRect(find.text('Hello'));
     final Rect trailingRect = tester.getRect(find.byIcon(Icons.expand_more));
     final Rect listTileRect = tester.getRect(find.byType(ListTile));
     final Rect tallerWidget = titleRect.height > trailingRect.height ? titleRect : trailingRect;

     // Check the positions of title and trailing Widgets, after padding is applied.
     expect(listTileRect.left, titleRect.left - 8);
     expect(listTileRect.right, trailingRect.right + 4);

     // Calculate the remaining height of ListTile from the default height.
     final double remainingHeight = 56 - tallerWidget.height;
     expect(listTileRect.top, tallerWidget.top - remainingHeight / 2 - 12);
     expect(listTileRect.bottom, tallerWidget.bottom + remainingHeight / 2 + 10);
   });

   testWidgets('ExpansionTile expandedAlignment test', (WidgetTester tester) async {
     await tester.pumpWidget(MaterialApp(
       home: Material(
         child: Center(
           child: ExpansionTile(
             title: const Text('title'),
             expandedAlignment: Alignment.centerLeft,
             children: <Widget>[
               Container(height: 100, width: 100),
               Container(height: 100, width: 80),
             ],
           ),
         ),
       ),
     ));

     await tester.tap(find.text('title'));
     await tester.pumpAndSettle();

     final Rect columnRect = tester.getRect(find.byType(Column).last);

     // The expandedAlignment is used to define the alignment of the Column widget in
     // expanded tile, not the alignment of the children inside the Column.
     expect(columnRect.left, 0.0);
     // The width of the Column is the width of the largest child. The largest width
     // being 100.0, the offset of the right edge of Column from X-axis should be 100.0.
     expect(columnRect.right, 100.0);
   });

   testWidgets('ExpansionTile expandedCrossAxisAlignment test', (WidgetTester tester) async {
     const Key child0Key = Key('child0');
     const Key child1Key = Key('child1');

     await tester.pumpWidget(MaterialApp(
       home: Material(
         child: Center(
           child: ExpansionTile(
             title: const Text('title'),
             // Set the column's alignment to Alignment.centerRight to test CrossAxisAlignment
             // of children widgets. This helps distinguish the effect of expandedAlignment
             // and expandedCrossAxisAlignment later in the test.
             expandedAlignment: Alignment.centerRight,
             expandedCrossAxisAlignment: CrossAxisAlignment.start,
             children: <Widget>[
               Container(height: 100, width: 100, key: child0Key),
               Container(height: 100, width: 80, key: child1Key),
             ],
           ),
         ),
       ),
     ));

     await tester.tap(find.text('title'));
     await tester.pumpAndSettle();

     final Rect columnRect = tester.getRect(find.byType(Column).last);
     final Rect child0Rect = tester.getRect(find.byKey(child0Key));
     final Rect child1Rect = tester.getRect(find.byKey(child1Key));

     // Since expandedAlignment is set to Alignment.centerRight, the column of children
     // should be aligned to the center right of the expanded tile. This provides confirmation
     // that the expandedCrossAxisAlignment.start is 700.0, where columnRect.left is.
     expect(columnRect.right, 800.0);
     // The width of the Column is the width of the largest child. The largest width
     // being 100.0, the offset of the left edge of Column from X-axis should be 700.0.
     expect(columnRect.left, 700.0);

     // Considering the value of expandedCrossAxisAlignment is CrossAxisAlignment.start,
     // the offset of the left edge of both the children from X-axis should be 700.0.
     expect(child0Rect.left, 700.0);
     expect(child1Rect.left, 700.0);
   });

   testWidgets('CrossAxisAlignment.baseline is not allowed', (WidgetTester tester) async {
     try {
       MaterialApp(
         home: Material(
           child: ExpansionTile(
             initiallyExpanded: true,
             title: const Text('title'),
             expandedCrossAxisAlignment: CrossAxisAlignment.baseline,
           ),
         ),
       );
     } on AssertionError catch (error) {
       expect(error.toString(), contains('CrossAxisAlignment.baseline is not supported since the expanded'
           ' children are aligned in a column, not a row. Try to use another constant.'));
       return;
     }
     fail('AssertionError was not thrown when expandedCrossAxisAlignment is CrossAxisAlignment.baseline.');
   });

   testWidgets('expandedCrossAxisAlignment and expandedAlignment default values', (WidgetTester tester) async {
     const Key child1Key = Key('child1');

     await tester.pumpWidget(MaterialApp(
       home: Material(
         child: Center(
           child: ExpansionTile(
             title: const Text('title'),
             children: <Widget>[
               Container(height: 100, width: 100),
               Container(height: 100, width: 80, key: child1Key),
             ],
           ),
         ),
       ),
     ));


     await tester.tap(find.text('title'));
     await tester.pumpAndSettle();

     final Rect columnRect = tester.getRect(find.byType(Column).last);
     final Rect child1Rect = tester.getRect(find.byKey(child1Key));

     // The default viewport size is Size(800, 600).
     // By default the value of extendedAlignment is Alignment.center, hence the offset
     // of left and right edges from x axis should be equal.
     expect(columnRect.left, 800 - columnRect.right);

     // By default the value of extendedCrossAxisAlignment is CrossAxisAlignment.center, hence
     // the offset of left and right edges from Column should be equal.
     expect(child1Rect.left - columnRect.left, columnRect.right - child1Rect.right);

   });

   testWidgets('childrenPadding default value', (WidgetTester tester) async {
     await tester.pumpWidget(MaterialApp(
       home: Material(
         child: Center(
           child: ExpansionTile(
             title: const Text('title'),
             children: <Widget>[
               Container(height: 100, width: 100),
             ],
           ),
         ),
       ),
     ));

     await tester.tap(find.text('title'));
     await tester.pumpAndSettle();

     final Rect columnRect = tester.getRect(find.byType(Column).last);
     final Rect paddingRect = tester.getRect(find.byType(Padding).last);

     // By default, the value of childrenPadding is EdgeInsets.zero, hence offset
     // of all the edges from x-axis and y-axis should be equal for Padding and Column.
     expect(columnRect.top, paddingRect.top);
     expect(columnRect.left, paddingRect.left);
     expect(columnRect.right, paddingRect.right);
     expect(columnRect.bottom, paddingRect.bottom);
   });

   testWidgets('ExpansionTile childrenPadding test', (WidgetTester tester) async {
     await tester.pumpWidget(MaterialApp(
       home: Material(
         child: Center(
           child: ExpansionTile(
             title: const Text('title'),
             childrenPadding: const EdgeInsets.fromLTRB(10, 8, 12, 4),
             children: <Widget>[
               Container(height: 100, width: 100),
             ],
           ),
         ),
       ),
     ));

     await tester.tap(find.text('title'));
     await tester.pumpAndSettle();

     final Rect columnRect = tester.getRect(find.byType(Column).last);
     final Rect paddingRect = tester.getRect(find.byType(Padding).last);

     // Check the offset of all the edges from x-axis and y-axis after childrenPadding
     // is applied.
     expect(columnRect.left, paddingRect.left + 10);
     expect(columnRect.top, paddingRect.top + 8);
     expect(columnRect.right, paddingRect.right - 12);
     expect(columnRect.bottom, paddingRect.bottom - 4);
   });

 }
	// 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_test/flutter_test.dart';
	import 'package:flutter/widgets.dart';
	import 'package:flutter/material.dart';

	class TestIcon extends StatefulWidget {
	const TestIcon({Key? key}) : super(key: key);

	@override
	TestIconState createState() => TestIconState();
	}

	class TestIconState extends State<TestIcon> {
	late IconThemeData iconTheme;

	@override
	Widget build(BuildContext context) {
	iconTheme = IconTheme.of(context);
	return const Icon(Icons.expand_more);
	}
	}

	class TestText extends StatefulWidget {
	const TestText(this.text, {Key? key}) : super(key: key);

	final String text;

	@override
	TestTextState createState() => TestTextState();
	}

	class TestTextState extends State<TestText> {
	late TextStyle textStyle;

	@override
	Widget build(BuildContext context) {
	textStyle = DefaultTextStyle.of(context).style;
	return Text(widget.text);
	}
	}

	void main() {
	const Color _dividerColor = Color(0x1f333333);
	const Color _accentColor = Colors.blueAccent;
	const Color _unselectedWidgetColor = Colors.black54;
	const Color _headerColor = Colors.black45;

	testWidgets('ExpansionTile initial state', (WidgetTester tester) async {
	final Key topKey = UniqueKey();
	const Key expandedKey = PageStorageKey<String>('expanded');
	const Key collapsedKey = PageStorageKey<String>('collapsed');
	const Key defaultKey = PageStorageKey<String>('default');

	final Key tileKey = UniqueKey();

	await tester.pumpWidget(MaterialApp(
	theme: ThemeData(
	dividerColor: _dividerColor,
	),
	home: Material(
	child: SingleChildScrollView(
	child: Column(
	children: <Widget>[
	ListTile(title: const Text('Top'), key: topKey),
	ExpansionTile(
	key: expandedKey,
	initiallyExpanded: true,
	title: const Text('Expanded'),
	backgroundColor: Colors.red,
	children: <Widget>[
	ListTile(
	key: tileKey,
	title: const Text('0'),
	),
	],
	),
	ExpansionTile(
	key: collapsedKey,
	initiallyExpanded: false,
	title: const Text('Collapsed'),
	children: <Widget>[
	ListTile(
	key: tileKey,
	title: const Text('0'),
	),
	],
	),
	const ExpansionTile(
	key: defaultKey,
	title: Text('Default'),
	children: <Widget>[
	ListTile(title: Text('0')),
	],
	),
	],
	),
	),
	),
	));

	double getHeight(Key key) => tester.getSize(find.byKey(key)).height;
	Container getContainer(Key key) => tester.firstWidget(find.descendant(
	of: find.byKey(key),
	matching: find.byType(Container),
	));

	expect(getHeight(topKey), getHeight(expandedKey) - getHeight(tileKey) - 2.0);
	expect(getHeight(topKey), getHeight(collapsedKey) - 2.0);
	expect(getHeight(topKey), getHeight(defaultKey) - 2.0);

	BoxDecoration expandedContainerDecoration = getContainer(expandedKey).decoration! as BoxDecoration;
	expect(expandedContainerDecoration.color, Colors.red);
	expect(expandedContainerDecoration.border!.top.color, _dividerColor);
	expect(expandedContainerDecoration.border!.bottom.color, _dividerColor);

	BoxDecoration collapsedContainerDecoration = getContainer(collapsedKey).decoration! as BoxDecoration;
	expect(collapsedContainerDecoration.color, Colors.transparent);
	expect(collapsedContainerDecoration.border!.top.color, Colors.transparent);
	expect(collapsedContainerDecoration.border!.bottom.color, Colors.transparent);

	await tester.tap(find.text('Expanded'));
	await tester.tap(find.text('Collapsed'));
	await tester.tap(find.text('Default'));

	await tester.pump();

	// Pump to the middle of the animation for expansion.
	await tester.pump(const Duration(milliseconds: 100));
	final BoxDecoration collapsingContainerDecoration = getContainer(collapsedKey).decoration! as BoxDecoration;
	expect(collapsingContainerDecoration.color, Colors.transparent);
	// Opacity should change but color component should remain the same.
	expect(collapsingContainerDecoration.border!.top.color, const Color(0x15333333));
	expect(collapsingContainerDecoration.border!.bottom.color, const Color(0x15333333));

	// Pump all the way to the end now.
	await tester.pump(const Duration(seconds: 1));

	expect(getHeight(topKey), getHeight(expandedKey) - 2.0);
	expect(getHeight(topKey), getHeight(collapsedKey) - getHeight(tileKey) - 2.0);
	expect(getHeight(topKey), getHeight(defaultKey) - getHeight(tileKey) - 2.0);

	// Expanded should be collapsed now.
	expandedContainerDecoration = getContainer(expandedKey).decoration! as BoxDecoration;
	expect(expandedContainerDecoration.color, Colors.transparent);
	expect(expandedContainerDecoration.border!.top.color, Colors.transparent);
	expect(expandedContainerDecoration.border!.bottom.color, Colors.transparent);

	// Collapsed should be expanded now.
	collapsedContainerDecoration = getContainer(collapsedKey).decoration! as BoxDecoration;
	expect(collapsedContainerDecoration.color, Colors.transparent);
	expect(collapsedContainerDecoration.border!.top.color, _dividerColor);
	expect(collapsedContainerDecoration.border!.bottom.color, _dividerColor);
	}, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS, TargetPlatform.macOS }));

	testWidgets('ListTileTheme', (WidgetTester tester) async {
	final Key expandedTitleKey = UniqueKey();
	final Key collapsedTitleKey = UniqueKey();
	final Key expandedIconKey = UniqueKey();
	final Key collapsedIconKey = UniqueKey();

	await tester.pumpWidget(
	MaterialApp(
	theme: ThemeData(
	accentColor: _accentColor,
	unselectedWidgetColor: _unselectedWidgetColor,
	textTheme: const TextTheme(subtitle1: TextStyle(color: _headerColor)),
	),
	home: Material(
	child: SingleChildScrollView(
	child: Column(
	children: <Widget>[
	const ListTile(title: Text('Top')),
	ExpansionTile(
	initiallyExpanded: true,
	title: TestText('Expanded', key: expandedTitleKey),
	backgroundColor: Colors.red,
	children: const <Widget>[ListTile(title: Text('0'))],
	trailing: TestIcon(key: expandedIconKey),
	),
	ExpansionTile(
	initiallyExpanded: false,
	title: TestText('Collapsed', key: collapsedTitleKey),
	children: const <Widget>[ListTile(title: Text('0'))],
	trailing: TestIcon(key: collapsedIconKey),
	),
	],
	),
	),
	),
	),
	);

	Color iconColor(Key key) => tester.state<TestIconState>(find.byKey(key)).iconTheme.color!;
	Color textColor(Key key) => tester.state<TestTextState>(find.byKey(key)).textStyle.color!;

	expect(textColor(expandedTitleKey), _accentColor);
	expect(textColor(collapsedTitleKey), _headerColor);
	expect(iconColor(expandedIconKey), _accentColor);
	expect(iconColor(collapsedIconKey), _unselectedWidgetColor);

	// Tap both tiles to change their state: collapse and extend respectively
	await tester.tap(find.text('Expanded'));
	await tester.tap(find.text('Collapsed'));
	await tester.pump();
	await tester.pump(const Duration(seconds: 1));
	await tester.pump(const Duration(seconds: 1));

	expect(textColor(expandedTitleKey), _headerColor);
	expect(textColor(collapsedTitleKey), _accentColor);
	expect(iconColor(expandedIconKey), _unselectedWidgetColor);
	expect(iconColor(collapsedIconKey), _accentColor);
	}, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS, TargetPlatform.macOS }));

	testWidgets('ExpansionTile subtitle', (WidgetTester tester) async {
	await tester.pumpWidget(
	const MaterialApp(
	home: Scaffold(
	body: ExpansionTile(
	title: Text('Title'),
	subtitle: Text('Subtitle'),
	children: <Widget>[ListTile(title: Text('0'))],
	),
	),
	),
	);

	expect(find.text('Subtitle'), findsOneWidget);
	});

	testWidgets('ExpansionTile maintainState', (WidgetTester tester) async {
	await tester.pumpWidget(
	MaterialApp(
	theme: ThemeData(
	platform: TargetPlatform.iOS,
	dividerColor: _dividerColor,
	),
	home: Material(
	child: SingleChildScrollView(
	child: Column(
	children: const <Widget>[
	ExpansionTile(
	title: Text('Tile 1'),
	initiallyExpanded: false,
	maintainState: true,
	children: <Widget>[
	Text('Maintaining State'),
	],
	),
	ExpansionTile(
	title: Text('Title 2'),
	initiallyExpanded: false,
	maintainState: false,
	children: <Widget>[
	Text('Discarding State'),
	],
	),
	],
	),
	),
	),
	));

	// This text should be offstage while ExpansionTile collapsed
	expect(find.text('Maintaining State', skipOffstage: false), findsOneWidget);
	expect(find.text('Maintaining State'), findsNothing);
	// This text shouldn't be there while ExpansionTile collapsed
	expect(find.text('Discarding State'), findsNothing);
	});

	testWidgets('ExpansionTile padding test', (WidgetTester tester) async {
	await tester.pumpWidget(const MaterialApp(
	home: Material(
	child: Center(
	child: ExpansionTile(
	title: Text('Hello'),
	tilePadding: EdgeInsets.fromLTRB(8, 12, 4, 10),
	),
	),
	),
	));

	final Rect titleRect = tester.getRect(find.text('Hello'));
	final Rect trailingRect = tester.getRect(find.byIcon(Icons.expand_more));
	final Rect listTileRect = tester.getRect(find.byType(ListTile));
	final Rect tallerWidget = titleRect.height > trailingRect.height ? titleRect : trailingRect;

	// Check the positions of title and trailing Widgets, after padding is applied.
	expect(listTileRect.left, titleRect.left - 8);
	expect(listTileRect.right, trailingRect.right + 4);

	// Calculate the remaining height of ListTile from the default height.
	final double remainingHeight = 56 - tallerWidget.height;
	expect(listTileRect.top, tallerWidget.top - remainingHeight / 2 - 12);
	expect(listTileRect.bottom, tallerWidget.bottom + remainingHeight / 2 + 10);
	});

	testWidgets('ExpansionTile expandedAlignment test', (WidgetTester tester) async {
	await tester.pumpWidget(MaterialApp(
	home: Material(
	child: Center(
	child: ExpansionTile(
	title: const Text('title'),
	expandedAlignment: Alignment.centerLeft,
	children: <Widget>[
	Container(height: 100, width: 100),
	Container(height: 100, width: 80),
	],
	),
	),
	),
	));

	await tester.tap(find.text('title'));
	await tester.pumpAndSettle();

	final Rect columnRect = tester.getRect(find.byType(Column).last);

	// The expandedAlignment is used to define the alignment of the Column widget in
	// expanded tile, not the alignment of the children inside the Column.
	expect(columnRect.left, 0.0);
	// The width of the Column is the width of the largest child. The largest width
	// being 100.0, the offset of the right edge of Column from X-axis should be 100.0.
	expect(columnRect.right, 100.0);
	});

	testWidgets('ExpansionTile expandedCrossAxisAlignment test', (WidgetTester tester) async {
	const Key child0Key = Key('child0');
	const Key child1Key = Key('child1');

	await tester.pumpWidget(MaterialApp(
	home: Material(
	child: Center(
	child: ExpansionTile(
	title: const Text('title'),
	// Set the column's alignment to Alignment.centerRight to test CrossAxisAlignment
	// of children widgets. This helps distinguish the effect of expandedAlignment
	// and expandedCrossAxisAlignment later in the test.
	expandedAlignment: Alignment.centerRight,
	expandedCrossAxisAlignment: CrossAxisAlignment.start,
	children: <Widget>[
	Container(height: 100, width: 100, key: child0Key),
	Container(height: 100, width: 80, key: child1Key),
	],
	),
	),
	),
	));

	await tester.tap(find.text('title'));
	await tester.pumpAndSettle();

	final Rect columnRect = tester.getRect(find.byType(Column).last);
	final Rect child0Rect = tester.getRect(find.byKey(child0Key));
	final Rect child1Rect = tester.getRect(find.byKey(child1Key));

	// Since expandedAlignment is set to Alignment.centerRight, the column of children
	// should be aligned to the center right of the expanded tile. This provides confirmation
	// that the expandedCrossAxisAlignment.start is 700.0, where columnRect.left is.
	expect(columnRect.right, 800.0);
	// The width of the Column is the width of the largest child. The largest width
	// being 100.0, the offset of the left edge of Column from X-axis should be 700.0.
	expect(columnRect.left, 700.0);

	// Considering the value of expandedCrossAxisAlignment is CrossAxisAlignment.start,
	// the offset of the left edge of both the children from X-axis should be 700.0.
	expect(child0Rect.left, 700.0);
	expect(child1Rect.left, 700.0);
	});

	testWidgets('CrossAxisAlignment.baseline is not allowed', (WidgetTester tester) async {
	try {
	MaterialApp(
	home: Material(
	child: ExpansionTile(
	initiallyExpanded: true,
	title: const Text('title'),
	expandedCrossAxisAlignment: CrossAxisAlignment.baseline,
	),
	),
	);
	} on AssertionError catch (error) {
	expect(error.toString(), contains('CrossAxisAlignment.baseline is not supported since the expanded'
	' children are aligned in a column, not a row. Try to use another constant.'));
	return;
	}
	fail('AssertionError was not thrown when expandedCrossAxisAlignment is CrossAxisAlignment.baseline.');
	});

	testWidgets('expandedCrossAxisAlignment and expandedAlignment default values', (WidgetTester tester) async {
	const Key child1Key = Key('child1');

	await tester.pumpWidget(MaterialApp(
	home: Material(
	child: Center(
	child: ExpansionTile(
	title: const Text('title'),
	children: <Widget>[
	Container(height: 100, width: 100),
	Container(height: 100, width: 80, key: child1Key),
	],
	),
	),
	),
	));


	await tester.tap(find.text('title'));
	await tester.pumpAndSettle();

	final Rect columnRect = tester.getRect(find.byType(Column).last);
	final Rect child1Rect = tester.getRect(find.byKey(child1Key));

	// The default viewport size is Size(800, 600).
	// By default the value of extendedAlignment is Alignment.center, hence the offset
	// of left and right edges from x axis should be equal.
	expect(columnRect.left, 800 - columnRect.right);

	// By default the value of extendedCrossAxisAlignment is CrossAxisAlignment.center, hence
	// the offset of left and right edges from Column should be equal.
	expect(child1Rect.left - columnRect.left, columnRect.right - child1Rect.right);

	});

	testWidgets('childrenPadding default value', (WidgetTester tester) async {
	await tester.pumpWidget(MaterialApp(
	home: Material(
	child: Center(
	child: ExpansionTile(
	title: const Text('title'),
	children: <Widget>[
	Container(height: 100, width: 100),
	],
	),
	),
	),
	));

	await tester.tap(find.text('title'));
	await tester.pumpAndSettle();

	final Rect columnRect = tester.getRect(find.byType(Column).last);
	final Rect paddingRect = tester.getRect(find.byType(Padding).last);

	// By default, the value of childrenPadding is EdgeInsets.zero, hence offset
	// of all the edges from x-axis and y-axis should be equal for Padding and Column.
	expect(columnRect.top, paddingRect.top);
	expect(columnRect.left, paddingRect.left);
	expect(columnRect.right, paddingRect.right);
	expect(columnRect.bottom, paddingRect.bottom);
	});

	testWidgets('ExpansionTile childrenPadding test', (WidgetTester tester) async {
	await tester.pumpWidget(MaterialApp(
	home: Material(
	child: Center(
	child: ExpansionTile(
	title: const Text('title'),
	childrenPadding: const EdgeInsets.fromLTRB(10, 8, 12, 4),
	children: <Widget>[
	Container(height: 100, width: 100),
	],
	),
	),
	),
	));

	await tester.tap(find.text('title'));
	await tester.pumpAndSettle();

	final Rect columnRect = tester.getRect(find.byType(Column).last);
	final Rect paddingRect = tester.getRect(find.byType(Padding).last);

	// Check the offset of all the edges from x-axis and y-axis after childrenPadding
	// is applied.
	expect(columnRect.left, paddingRect.left + 10);
	expect(columnRect.top, paddingRect.top + 8);
	expect(columnRect.right, paddingRect.right - 12);
	expect(columnRect.bottom, paddingRect.bottom - 4);
	});

	}