| // 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 |
| /// with no [orElse] function provided, the future will receive an error. |
| /// @author kaigorodov |
| |
| import "dart:async"; |
| import "../../../Utils/expect.dart"; |
| import "IsolateStream.dart" as IsolateStream; |
| |
| check(Iterable data, bool test(var element)) { |
| Stream s = IsolateStream.fromIterable(data); |
| asyncStart(); |
| s.lastWhere(test).then((data) { |
| Expect.fail("data passed: $data"); |
| }, onError: (error) { |
| Expect.isTrue(error is Error); |
| asyncEnd(); |
| }); |
| } |
| |
| main() { |
| check([], (var element) => true); |
| check([1, 2, 3], (var element) => element == null); |
| check([null, null], (var element) => element != null); |
| check(new Iterable.generate(0, (int index) => index), (var element) => false); |
| check( |
| new Iterable.generate(10, (int index) => index), (var element) => false); |
| check(new Iterable.generate(10, (int index) => index * 5), |
| (var element) => element < 0); |
| check(new Iterable.generate(10, (int index) => index * 5), |
| (var element) => element == 300); |
| } |