LibTest/async/StreamTransformer/StreamTransformer_A02_t02.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 factory StreamTransformer(StreamSubscription<T>
 *   transformer(Stream<S> stream, bool cancelOnError))
 * Creates a StreamTransformer.
 *
 * The transformer closure receives the stream, that was bound, as argument
 * and returns a StreamSubscription. In almost all cases the closure listens
 * itself to the stream that is given as argument.
 *
 * @description Checks that transformer will listen to whatever stream the
 * the returned StreamSubscription is created for.
 * @author ilya
 */
import "dart:async";
import "../../../Utils/async_utils.dart";
import "../../../Utils/expect.dart";

main() {
  var s = new Stream.fromIterable([1]);
  var tr = new StreamTransformer((_, __) {
    var s2 = new Stream.fromIterable([2]);
    return s2.listen(null);
  });

  asyncStart();
  s.transform(tr).toList().then((x) {
    Expect.listEquals([2], x);
    asyncEnd();
  });
}