packages/flutter/test/scheduler/ticker_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/scheduler.dart';
import 'package:flutter/services.dart';
import 'package:flutter_test/flutter_test.dart';

void main() {
  testWidgets('Ticker mute control test', (WidgetTester tester) async {
    int tickCount = 0;
    void handleTick(Duration duration) {
      tickCount += 1;
    }

    final Ticker ticker = Ticker(handleTick);

    expect(ticker.isTicking, isFalse);
    expect(ticker.isActive, isFalse);

    ticker.start();

    expect(ticker.isTicking, isTrue);
    expect(ticker.isActive, isTrue);
    expect(tickCount, equals(0));

    expect(ticker.start, throwsFlutterError);

    await tester.pump(const Duration(milliseconds: 10));

    expect(tickCount, equals(1));

    ticker.muted = true;
    await tester.pump(const Duration(milliseconds: 10));

    expect(tickCount, equals(1));
    expect(ticker.isTicking, isFalse);
    expect(ticker.isActive, isTrue);

    ticker.muted = false;
    await tester.pump(const Duration(milliseconds: 10));

    expect(tickCount, equals(2));
    expect(ticker.isTicking, isTrue);
    expect(ticker.isActive, isTrue);

    ticker.muted = true;
    await tester.pump(const Duration(milliseconds: 10));

    expect(tickCount, equals(2));
    expect(ticker.isTicking, isFalse);
    expect(ticker.isActive, isTrue);

    ticker.stop();

    expect(tickCount, equals(2));
    expect(ticker.isTicking, isFalse);
    expect(ticker.isActive, isFalse);

    ticker.muted = false;

    expect(tickCount, equals(2));
    expect(ticker.isTicking, isFalse);
    expect(ticker.isActive, isFalse);

    await tester.pump(const Duration(milliseconds: 10));

    expect(tickCount, equals(2));
    expect(ticker.isTicking, isFalse);
    expect(ticker.isActive, isFalse);
  });

  testWidgets('Ticker control test', (WidgetTester tester) async {
    Ticker ticker;

    void testFunction() {
      ticker = Ticker(null);
    }

    testFunction();

    expect(ticker, hasOneLineDescription);
    expect(ticker.toString(debugIncludeStack: true), contains('testFunction'));
  });

  testWidgets('Ticker can be sped up with time dilation', (WidgetTester tester) async {
    timeDilation = 0.5; // Move twice as fast.
    Duration lastDuration;
    void handleTick(Duration duration) {
      lastDuration = duration;
    }

    final Ticker ticker = Ticker(handleTick);
    ticker.start();
    await tester.pump(const Duration(milliseconds: 10));
    await tester.pump(const Duration(milliseconds: 10));
    expect(lastDuration, const Duration(milliseconds: 20));

    ticker.dispose();
  });

  testWidgets('Ticker can be slowed down with time dilation', (WidgetTester tester) async {
    timeDilation = 2.0; // Move half as fast.
    Duration lastDuration;
    void handleTick(Duration duration) {
      lastDuration = duration;
    }

    final Ticker ticker = Ticker(handleTick);
    ticker.start();
    await tester.pump(const Duration(milliseconds: 10));
    await tester.pump(const Duration(milliseconds: 10));
    expect(lastDuration, const Duration(milliseconds: 5));

    ticker.dispose();
  });

  testWidgets('Ticker stops ticking when application is paused', (WidgetTester tester) async {
    int tickCount = 0;
    void handleTick(Duration duration) {
      tickCount += 1;
    }

    final Ticker ticker = Ticker(handleTick);
    ticker.start();

    expect(ticker.isTicking, isTrue);
    expect(ticker.isActive, isTrue);
    expect(tickCount, equals(0));

    final ByteData message = const StringCodec().encodeMessage('AppLifecycleState.paused');
    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', message, (_) { });
    expect(ticker.isTicking, isFalse);
    expect(ticker.isActive, isTrue);

    ticker.stop();
  });

  testWidgets('Ticker can be created before application unpauses', (WidgetTester tester) async {
    final ByteData pausedMessage = const StringCodec().encodeMessage('AppLifecycleState.paused');
    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', pausedMessage, (_) { });

    int tickCount = 0;
    void handleTick(Duration duration) {
      tickCount += 1;
    }

    final Ticker ticker = Ticker(handleTick);
    ticker.start();

    expect(tickCount, equals(0));
    expect(ticker.isTicking, isFalse);

    await tester.pump(const Duration(milliseconds: 10));

    expect(tickCount, equals(0));
    expect(ticker.isTicking, isFalse);

    final ByteData resumedMessage = const StringCodec().encodeMessage('AppLifecycleState.resumed');
    await BinaryMessages.handlePlatformMessage('flutter/lifecycle', resumedMessage, (_) { });

    await tester.pump(const Duration(milliseconds: 10));

    expect(tickCount, equals(1));
    expect(ticker.isTicking, isTrue);

    ticker.stop();
  });
}