LibTest/async/Stream/asBroadcastStream_A03_t02.test.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 Stream<T> asBroadcastStream (
///   {void onListen(StreamSubscription<T> subscription),
///    void onCancel(StreamSubscription<T> subscription)})
/// Returns a multi-subscription stream that produces the same events as this.
///
/// If onListen is provided, it is called with a subscription-like object that
/// represents the underlying subscription to this stream. It is possible to
/// pause, resume or cancel the subscription during the call to onListen. It
/// is not possible to change the event handlers, including using
/// StreamSubscription.asFuture.
///
/// @description Checks that it is a runtime error to try to change event
/// handlers for underlying subscription.
/// @author ilya
/// @author a.semenov@unipro.ru

library asBroadcastStream_A03_t02;
import "dart:async";
import "../../../Utils/expect.dart";

void test(CreateStreamFunction create) {
  Stream<int> s = create([1,2,3]);
  s.asBroadcastStream(onListen: (StreamSubscription ss) {
    Expect.throws(()=>ss.onData((_){}));
  }).listen((_){});
}