| // 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> lastWhere(bool test(T element), {T orElse()?}) |
| /// |
| /// Finds the last element in this stream matching test. |
| /// |
| /// Returns a future that is completed with the last element of this stream for |
| /// which test returns true. |
| /// |
| /// If no such element is found before this stream is done, and an orElse |
| /// function is provided, the result of calling orElse becomes the value of the |
| /// future. If orElse throws, the returned future is completed with that error. |
| /// |
| /// If this stream emits an error at any point, the returned future is completed |
| /// with that error, and the subscription is canceled. |
| /// |
| /// A non-error result cannot be provided before this stream is done. |
| /// |
| /// Similar too firstWhere, except that the last matching element is found |
| /// instead of the first. |
| /// |
| /// @description Checks that if this stream ends without finding a match and an |
| /// [orElse] function is provided, the result of calling [orElse] becomes the |
| /// value of the future. |
| /// @author kaigorodov |
| |
| library lastWhere_A02_t01; |
| |
| import "dart:async"; |
| import "../../../Utils/expect.dart"; |
| |
| void check<T>(Stream<T> s, bool test(T element), T expected) { |
| AsyncExpect.value(expected, s.lastWhere(test, orElse: () => expected)); |
| } |
| |
| void test(CreateStreamFunction create) { |
| check(create([]), (element) => true, 1); |
| check<int?>(create([1, 2, 3]), (int? element) => element == null, 42); |
| check(create(new Iterable.generate(0, (int index) => index)), |
| (int element) => false, 0); |
| check(create(new Iterable.generate(0, (int index) => index)), |
| (int element) => true, 0); |
| check(create(new Iterable.generate(10, (int index) => index)), |
| (int element) => false, 22); |
| check(create(new Iterable.generate(10, (int index) => index * 5)), |
| (int element) => element < 0, 33); |
| } |