LibTest/async/Stream/takeWhile_A01_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> takeWhile(bool test(T element))
/// Forwards data events while test is successful.
/// The returned stream provides the same events as this stream as long as test
/// returns true for the event data.
/// The stream is done when either this stream is done, or when this stream
/// first provides a value that test doesn't accept.
/// @description Checks that all error events (which occur before the returned
/// stream is done) are submitted to the returned stream.
/// Checks that the resulting stream ends with a done event.
/// @author a.semenov@unipro.ru

library takeWhile_A01_t02;

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

void check<T>(Stream<T> s, bool test(T element), List<T> expectedData,
    List expectedErrors) {
  AsyncExpect.events(expectedData, expectedErrors, s.takeWhile(test));
}

void test(CreateStreamWithErrorsFunction create) {
  check(create([1, 2, 3], isError: (_) => true, defaultValue: 42), (x) => false,
      [], [1, 2, 3]);
  check(create([1, 2, 3], isError: (_) => true, defaultValue: 42), (x) => true,
      [], [1, 2, 3]);

  check(create<int>([1, 2, 3, 4, 5], isError: (x) => x.isOdd, defaultValue: 42),
      (x) => false, [], [1]);
  check<int>(
      create<int>([1, 2, 3, 4, 5], isError: (x) => x.isOdd, defaultValue: 42),
      (x) => x < 4, [2], [1, 3]);
  check(create<int>([1, 2, 3, 4, 5], isError: (x) => x.isEven, defaultValue: 42),
      (x) => false, [], []);
  check<int>(
      create<int>([1, 2, 3, 4, 5], isError: (x) => x.isEven, defaultValue: 42),
      (x) => x < 4, [1, 3], [2, 4]);

  check(create<int>([1, 2, 3, 4, 5], isError: (x) => x < 4, defaultValue: 42),
      (x) => true, [4, 5], [1, 2, 3]);
  check(create<int>([1, 2, 3, 4, 5], isError: (x) => x < 4, defaultValue: 42),
      (x) => false, [], [1, 2, 3]);
  check<int>(
      create<int>([1, 2, 3, 4, 5], isError: (x) => x < 4, defaultValue: 42),
      (x) => x > 2, [4, 5], [1, 2, 3]);
  check<int>(
      create<int>([1, 2, 3, 4, 5], isError: (x) => x > 2, defaultValue: 42),
      (x) => x < 3, [1, 2], [3, 4, 5]);
}