LibTest/async/Stream/reduce_A01_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 Future<T> reduce(T combine(T previous, T element))
 * Reduces a sequence of values by repeatedly applying combine.
 * @description Checks that if the stream contains single element, the combine method
 * is not called and that element is the result of the future.
 * @note undocumented
 * @author kaigorodov
 */

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

void check(Iterable data, combine(previous, var element), var expected) {
  Stream s=new Stream.fromIterable(data);
  asyncStart();
  Future f=s.reduce(combine);
  f.then((var actual){
    Expect.equals(expected, actual);
    asyncEnd();
  });
}

main() {
  check([777], null, 777);
}