| // Copyright (c) 2016, 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 previousEntry() → DoubleLinkedQueueEntry<E> |
| * Returns the previous entry or [null] if there is none. |
| * @description Checks that nextEntry() returns the next element |
| * @author sgrekhov@unipro.ru |
| */ |
| import "../../../Utils/expect.dart"; |
| import "dart:collection"; |
| |
| main() { |
| DoubleLinkedQueue queue = new DoubleLinkedQueue(); |
| queue.add(1); |
| queue.add(2); |
| queue.add(3); |
| |
| Expect.equals(2, queue.lastEntry()?.previousEntry()?.element); |
| Expect.equals(1, queue.lastEntry()?.previousEntry()?.previousEntry()?.element); |
| Expect.isNull(queue.firstEntry()?.previousEntry()); |
| } |