flutter_flutter/packages/flutter/test/rendering/object_test.dart

// Copyright 2017 The Chromium 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/material.dart';
import 'package:flutter/rendering.dart';
import 'package:test/test.dart';

void main() {
  test("ensure frame is scheduled for markNeedsSemanticsUpdate", () {
    final TestRenderObject renderObject = new TestRenderObject();
    int onNeedVisualUpdateCallCount = 0;
    final PipelineOwner owner = new PipelineOwner(onNeedVisualUpdate: () {
      onNeedVisualUpdateCallCount +=1;
    });
    owner.ensureSemantics();
    renderObject.attach(owner);
    owner.flushSemantics();

    expect(onNeedVisualUpdateCallCount, 1);
    renderObject.markNeedsSemanticsUpdate();
    expect(onNeedVisualUpdateCallCount, 2);
  });

  test("ensure frame is scheduled for markNeedsSemanticsUpdate with onlyChanges: true", () {
    final TestRenderObject renderObject = new TestRenderObject();
    int onNeedVisualUpdateCallCount = 0;
    final PipelineOwner owner = new PipelineOwner(onNeedVisualUpdate: () {
      onNeedVisualUpdateCallCount +=1;
    });
    owner.ensureSemantics();
    renderObject.attach(owner);
    owner.flushSemantics();

    expect(onNeedVisualUpdateCallCount, 1);
    renderObject.markNeedsSemanticsUpdate(onlyLocalUpdates: true);
    expect(onNeedVisualUpdateCallCount, 2);
  });
}

class TestRenderObject extends RenderObject {
  @override
  void debugAssertDoesMeetConstraints() {}

  @override
  Rect get paintBounds => null;

  @override
  void performLayout() {}

  @override
  void performResize() {}

  @override
  Rect get semanticBounds => new Rect.fromLTWH(0.0, 0.0, 10.0, 20.0);

  @override
  bool get isSemanticBoundary => true;
}