| // 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/rendering.dart'; |
| import 'package:flutter/widgets.dart'; |
| import 'package:flutter_test/flutter_test.dart'; |
| |
| void main() { |
| testWidgets('Render and element tree stay in sync when keyed children move around', (WidgetTester tester) async { |
| // Regression test for https://github.com/flutter/flutter/issues/48855. |
| |
| await tester.pumpWidget( |
| Directionality( |
| textDirection: TextDirection.ltr, |
| child: Column( |
| children: const <Widget>[ |
| Text('0', key: ValueKey<int>(0)), |
| Text('1', key: ValueKey<int>(1)), |
| Text('2', key: ValueKey<int>(2)), |
| Text('3', key: ValueKey<int>(3)), |
| Text('4', key: ValueKey<int>(4)), |
| Text('5', key: ValueKey<int>(5)), |
| Text('6', key: ValueKey<int>(6)), |
| Text('7', key: ValueKey<int>(7)), |
| Text('8', key: ValueKey<int>(8)), |
| ], |
| ), |
| ), |
| ); |
| |
| expect( |
| _getChildOrder(tester.renderObject<RenderFlex>(find.byType(Column))), |
| <String>['0', '1', '2', '3', '4', '5', '6', '7', '8'], |
| ); |
| |
| await tester.pumpWidget( |
| Directionality( |
| textDirection: TextDirection.ltr, |
| child: Column( |
| children: const <Widget>[ |
| Text('0', key: ValueKey<int>(0)), |
| Text('6', key: ValueKey<int>(6)), |
| Text('7', key: ValueKey<int>(7)), |
| Text('8', key: ValueKey<int>(8)), |
| Text('1', key: ValueKey<int>(1)), |
| Text('2', key: ValueKey<int>(2)), |
| Text('3', key: ValueKey<int>(3)), |
| Text('4', key: ValueKey<int>(4)), |
| Text('5', key: ValueKey<int>(5)), |
| ], |
| ), |
| ), |
| ); |
| |
| expect( |
| _getChildOrder(tester.renderObject<RenderFlex>(find.byType(Column))), |
| <String>['0', '6', '7', '8', '1', '2', '3', '4', '5'], |
| ); |
| }); |
| } |
| |
| // Do not use tester.renderObjectList(find.byType(RenderParagraph). That returns |
| // the RenderObjects in the order of their associated RenderObjectWidgets. The |
| // point of this test is to assert the children order in the render tree, though. |
| List<String> _getChildOrder(RenderFlex flex) { |
| final List<String> childOrder = <String>[]; |
| flex.visitChildren((RenderObject child) { |
| childOrder.add(((child as RenderParagraph).text as TextSpan).text); |
| }); |
| return childOrder; |
| } |