LibTest/async/StreamController/StreamController_A07_t01.dart

// Copyright (c) 2011, 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.

/// @assertion StreamController({void onListen(), void onPause(),
///                  void onResume(), dynamic onCancel(), bool sync: false})
/// If onCancel needs to perform an asynchronous operation, onCancel should
/// return a future that completes when the cancel operation is done.
///
/// @description Checks that stream subscription is cancelled only after
/// the Future returned by onCancel function is completed.
/// @author a.semenov@unipro.ru

import "dart:async";
import "../../../Utils/expect.dart";

main() {
  asyncStart();
  bool onCancelFutureComplete = false;
  StreamController controller = new StreamController(
      onCancel: () => new Future.delayed(durationInMilliseconds(100), () {
            onCancelFutureComplete = true;
          }));

  Expect.isFalse(onCancelFutureComplete);
  StreamSubscription subs = controller.stream.listen((event) {});

  new Future(() => subs.cancel()).then((_) {
    Expect.isTrue(onCancelFutureComplete);
    asyncEnd();
  });
}