LibTest/async/Stream/lastWhere_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.

// @dart = 2.9

/// @assertion Future<T> lastWhere (bool test(T element),
///     {@deprecated dynamic defaultValue(),  T orElse()})
///
/// Finds the last element in this stream matching test.
///
/// If this stream emits an error, the returned future is completed with that
/// error, and processing stops.
///
/// Otherwise as firstWhere, except that the last matching element is found
/// instead of the first. That means that a non-error result cannot be provided
/// before this stream is done.
///
/// The defaultValue parameter is deprecated, and orElse should be used instead.
/// @description Checks that if an error occurs in the stream, the future will
/// receive that error.
/// @author kaigorodov
/// @author a.semenov@unipro.ru

library lastWhere_A03_t01;
import "dart:async";
import "../../../Utils/expect.dart";

void check<T>(Stream<T> s, bool test(T element), Object expectedError) {
  AsyncExpect.error(expectedError, s.lastWhere(test));
}

void test(CreateStreamWithErrorsFunction create) {
  check(create([1,2,3], isError:(e) => true), (x) => x > 0, 1);
  check(create([1,2,3], isError:(e) => e == 3), (x) => x > 0, 3);
  check(create([-1,1,-2,2,3], isError:(e) => e == 3), (x) => x < 0, 3);
}