| // 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/foundation.dart'; |
| import 'package:flutter/material.dart'; |
| import 'package:flutter_test/flutter_test.dart'; |
| |
| // This file is for tests for WidgetsBinding that require a `LiveTestWidgetsFlutterBinding`. |
| void main() { |
| LiveTestWidgetsFlutterBinding(); |
| testWidgets('ReportTiming callback records the sendFramesToEngine when it was scheduled', (WidgetTester tester) async { |
| // Addresses https://github.com/flutter/flutter/issues/144261 |
| // This test needs LiveTestWidgetsFlutterBinding for multiple reasons. |
| // |
| // First, this was the environment that this bug was discovered. |
| // |
| // Second, unlike `AutomatedTestWidgetsFlutterBinding`, which overrides |
| // `scheduleWarmUpFrame` to execute the handlers synchronously, |
| // `LiveTestWidgetsFlutterBinding` still calls them asynchronously. This |
| // allows `runApp`, which also schedules a warm-up frame, to bind a widget |
| // without rendering a frame, which is needed to for `deferFirstFrame` to |
| // take effect. |
| |
| // Before `testWidgets` executes the test body, it pumps a frame with a |
| // fixed dummy widget, then calls `resetFirstFrameSent`. The pumped frame |
| // schedules a reportTiming call that has yet to arrive. |
| // |
| // This puts the test in an inconsistent state: a reportTiming callback is |
| // supposed to happen only after a frame is rendered, but due to |
| // `resetFirstFrameSent`, the framework thinks no frames have been rendered. |
| |
| expect(tester.binding.sendFramesToEngine, true); |
| // Push the widget with `runApp` instead of `tester.pump`, avoiding |
| // rendering a frame, which is needed for `deferFirstFrame` later to work. |
| runApp(const DummyWidget()); |
| // Verify that no widget tree is built and nothing is rendered. |
| expect(find.text('First frame'), findsNothing); |
| // Defer the first frame, making `sendFramesToEngine` false, so that widget |
| // tree will be built but not sent to the engine. |
| tester.binding.deferFirstFrame(); |
| expect(tester.binding.sendFramesToEngine, false); |
| // Pump a frame, letting the reportTiming callback to run. If the |
| // reportTiming callback were to assume that `sendFramesToEngine` is true, |
| // the callback would crash. |
| await tester.pump(const Duration(milliseconds: 1)); |
| await tester.binding.waitUntilFirstFrameRasterized; |
| expect(find.text('First frame'), findsOne); |
| }, skip: kIsWeb); // [intended] Web doesn't use LiveTestWidgetsFlutterBinding |
| } |
| |
| class DummyWidget extends StatelessWidget { |
| const DummyWidget({super.key}); |
| |
| @override |
| Widget build(BuildContext context) { |
| return const Directionality( |
| textDirection: TextDirection.ltr, |
| child: Center( |
| child: Text('First frame'), |
| ), |
| ); |
| } |
| } |