LibTest/async/Stream/reduce_A03_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> reduce(T combine(T previous, T element))
 * Reduces a sequence of values by repeatedly applying combine.
 * @description Checks that if stream contains error, then returned future is
 * completed with this error.
 * @author a.semenov@unipro.ru
 */
library reduce_A03_t01;
import "dart:async";
import "../../../Utils/expect.dart";

void check<T>(Stream<T> s, T combine(T p, T e), Object expected) {
  AsyncExpect.error(expected, s.reduce(combine));
}

void test(CreateStreamWithErrorsFunction create) {
  check(create([1, 2, 3, 4, 5], isError: (_) => true), (int p, int e) => p + e,
      1);
  check(create([1, 2, 3, 4, 5], isError: (x) => x.isEven),
      (int p, int e) => p * e, 2);
  check(create([1, 2, 3, 4, 5], isError: (x) => x == 5),
      (int p, int e) => p + e, 5);
}