// 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_test/flutter_test.dart'; import 'rendering_tester.dart'; void main() { TestRenderingFlutterBinding.ensureInitialized(); test('only send semantics update if semantics have changed', () { final TestRender testRender = TestRender() ..properties = const SemanticsProperties(label: 'hello') ..textDirection = TextDirection.ltr; final RenderConstrainedBox tree = RenderConstrainedBox( additionalConstraints: const BoxConstraints.tightFor(height: 20.0, width: 20.0), child: testRender, ); int semanticsUpdateCount = 0; final SemanticsHandle semanticsHandle = TestRenderingFlutterBinding.instance.pipelineOwner.ensureSemantics( listener: () { ++semanticsUpdateCount; }, ); layout(tree, phase: EnginePhase.flushSemantics); // Initial render does semantics. expect(semanticsUpdateCount, 1); expect(testRender.describeSemanticsConfigurationCallCount, isPositive); testRender.describeSemanticsConfigurationCallCount = 0; semanticsUpdateCount = 0; // Request semantics update even though nothing changed. testRender.markNeedsSemanticsUpdate(); pumpFrame(phase: EnginePhase.flushSemantics); // Object is asked for semantics, but no update is sent. expect(semanticsUpdateCount, 0); expect(testRender.describeSemanticsConfigurationCallCount, isPositive); testRender.describeSemanticsConfigurationCallCount = 0; semanticsUpdateCount = 0; // Change semantics and request update. testRender.properties = const SemanticsProperties(label: 'bye'); testRender.markNeedsSemanticsUpdate(); pumpFrame(phase: EnginePhase.flushSemantics); // Object is asked for semantics, and update is sent. expect(semanticsUpdateCount, 1); expect(testRender.describeSemanticsConfigurationCallCount, isPositive); semanticsHandle.dispose(); }); } class TestRender extends RenderSemanticsAnnotations { TestRender() : super(properties: const SemanticsProperties()); int describeSemanticsConfigurationCallCount = 0; @override void describeSemanticsConfiguration(SemanticsConfiguration config) { super.describeSemanticsConfiguration(config); describeSemanticsConfigurationCallCount += 1; } }