blob: 186025b2fbe6d81ba048c2525e4c0ed09dac98a4 [file] [log] [blame]
// 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;
}