| // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| // @dart = 2.9 |
| |
| // Test merging streams. |
| library dart.test.stream_from_iterable; |
| |
| import 'dart:async'; |
| |
| import 'package:async_helper/async_minitest.dart'; |
| |
| watchMs(Stopwatch watch) { |
| int microsecs = watch.elapsedMicroseconds; |
| // Give it some slack. The Stopwatch is more precise than the timers. This |
| // means that we sometimes get 3995 microseconds instead of 4+ milliseconds. |
| // 200 microseconds should largely account for this discrepancy. |
| return (microsecs + 200) ~/ 1000; |
| } |
| |
| main() { |
| test("stream-periodic4", () { |
| Stream stream = |
| new Stream.periodic(const Duration(milliseconds: 5), (x) => x); |
| Stopwatch watch = new Stopwatch()..start(); |
| var subscription; |
| subscription = stream.take(10).listen((i) { |
| int ms = watchMs(watch); |
| watch.reset(); |
| if (i == 2) { |
| Stopwatch watch2 = new Stopwatch()..start(); |
| // Busy wait. |
| while (watch2.elapsedMilliseconds < 15) {} |
| // Make sure the stream can be paused when it has overdue events. |
| // We just busy waited for 15ms, even though the stream is supposed to |
| // emit events every 5ms. |
| subscription.pause(); |
| watch.stop(); |
| new Timer(const Duration(milliseconds: 150), () { |
| watch.start(); |
| subscription.resume(); |
| }); |
| } |
| }, onDone: expectAsync(() {})); |
| }); |
| } |