blob: 2d19139bd0e947be3735cb5b5cd1d044f3a17aa5 [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/scheduler.dart';
import 'package:flutter/services.dart';
import 'package:flutter/widgets.dart';
import 'package:flutter_test/flutter_test.dart';
void main() {
test('Can only schedule frames after widget binding attaches the root widget', () async {
final WidgetsBinding binding = WidgetsFlutterBinding.ensureInitialized();
expect(SchedulerBinding.instance.framesEnabled, isFalse);
expect(SchedulerBinding.instance.hasScheduledFrame, isFalse);
// Sends a message to notify that the engine is ready to accept frames.
final ByteData message = const StringCodec().encodeMessage('AppLifecycleState.resumed')!;
await ServicesBinding.instance.defaultBinaryMessenger.handlePlatformMessage('flutter/lifecycle', message, (_) { });
// Enables the semantics should not schedule any frames if the root widget
// has not been attached.
binding.setSemanticsEnabled(true);
expect(SchedulerBinding.instance.framesEnabled, isFalse);
expect(SchedulerBinding.instance.hasScheduledFrame, isFalse);
// The widget binding should be ready to produce frames after it attaches
// the root widget.
binding.attachRootWidget(const Placeholder());
expect(SchedulerBinding.instance.framesEnabled, isTrue);
expect(SchedulerBinding.instance.hasScheduledFrame, isTrue);
});
}