| // Copyright (c) 2018, 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 that stream cancellation is checked immediately after delivering the |
| // event, and before continuing after the yield. |
| |
| import "dart:async"; |
| import "package:expect/expect.dart"; |
| import "package:async_helper/async_helper.dart"; |
| |
| main() async { |
| asyncStart(); |
| var log = []; |
| Stream<int> f() async* { |
| try { |
| log.add("-1"); |
| yield 1; |
| log.add("-2"); |
| yield 2; |
| } finally { |
| log.add("x"); |
| } |
| } |
| |
| var completer = Completer(); |
| var s; |
| s = f().listen((e) { |
| log.add("+$e"); |
| // The `cancel` operation makes all `yield` operations act as returns. |
| // It should make the `finally` block in `f` log an "x", |
| // and nothing else. |
| completer.complete(s.cancel()); |
| }, onError: (e) { |
| // Should never be reached, but if it does, we'll make the await |
| // below terminate. |
| completer.complete(new Future.sync(() { |
| Expect.fail("$e"); |
| })); |
| }, onDone: () { |
| completer.complete(null); |
| }); |
| await completer.future; |
| Expect.listEquals(["-1", "+1", "x"], log, "cancel"); |
| asyncEnd(); |
| } |