| // Copyright (c) 2016, 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 |
| |
| import "dart:async"; |
| import "package:expect/expect.dart"; |
| import "package:async_helper/async_helper.dart"; |
| |
| var events = []; |
| |
| ticker() async* { |
| var sc; |
| var sentTickCount = 0; |
| sc = new StreamController(onListen: () { |
| events.add("listen"); |
| }, onCancel: () { |
| events.add("cancel"); |
| }); |
| |
| try { |
| var counter = 0; |
| await for (var tick in sc.stream) { |
| counter++; |
| } |
| } finally { |
| events.add("finally"); |
| } |
| } |
| |
| void main() { |
| asyncStart(); |
| events.add("main"); |
| final subscription = ticker().listen((val) {}); |
| |
| bool cancelFinished = false; |
| // Cancel the subscription. |
| // The async* function is blocked on an `await` (the inner stream) and won't |
| // be able to complete. |
| Timer.run(() { |
| events.add("invoke cancel"); |
| subscription.cancel().then((_) => cancelFinished = true); |
| }); |
| |
| new Timer(const Duration(milliseconds: 100), () { |
| Expect.isFalse(cancelFinished); |
| Expect.listEquals(["main", "listen", "invoke cancel"], events); |
| asyncEnd(); |
| }); |
| } |