LibTest/async/Stream/first_A04_t01.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 Future<T> first
///    Stops listening to the stream after the first element has been received.
///    Internally the method cancels its subscription after the first element.
/// This means that single-subscription (non-broadcast) streams are closed and
/// cannot be reused after a call to this getter.
/// @description Checks that non broadcast stream can not be listened after
/// the first element is returned.
/// @author a.semenov@unipro.ru

library first_A04_t01;
import "dart:async";
import "../../../Utils/expect.dart";

void check(Stream s) {
  asyncStart();
  s.first.then(
    (_) {
      if (!s.isBroadcast){
        Expect.throws(() => s.listen((_){}));
      }
      asyncEnd();
    }
  );
}

void test(CreateStreamFunction create) {
  check(create([123]));
  check(create([1,2,3]));
}