LibTest/async/Stream/take_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.

// @dart = 2.9

/// @assertion Stream<T> take(int count)
/// Provides at most the first n values of this stream.
/// Forwards the first n data events of this stream, and all error events,
/// to the returned stream, and ends with a done event.
/// If this stream produces fewer than count values before it's done,
/// so will the returned stream.
/// @description Checks that all error events (which are before first n data
/// events) are submitted to the returned stream. Checks that the resulting
/// stream ends with a done event.
/// @author a.semenov@unipro.ru

library take_A01_t02;
import "dart:async";
import "../../../Utils/expect.dart";

void check<T>(Stream<T> s, int count, List<T> expectedData, List expectedErrors) {
  AsyncExpect.events(expectedData, expectedErrors, s.take(count));
}

void test(CreateStreamWithErrorsFunction create) {
  check(create([1, 2, 3], isError: (_) => true), 0, [], []);
  check(create([1, 2, 3], isError: (_) => true), 1, [], [1,2,3]);
  check(create([1, 2, 3], isError: (_) => true), 10, [], [1,2,3]);

  check(create([1, 2, 3, 4, 5], isError: (x) => x.isOdd), 10, [2,4], [1,3,5]);
  check(create([1, 2, 3, 4, 5], isError: (x) => x.isOdd), 2, [2,4], [1,3]);
  check(create([1, 2, 3, 4, 5], isError: (x) => x.isEven), 1, [1], []);
  check(create([1, 2, 3, 4, 5], isError: (x) => x.isEven), 2, [1,3], [2]);

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