|  | // Copyright (c) 2012, 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. | 
|  |  | 
|  | library queue.single.test; | 
|  |  | 
|  | import "package:expect/expect.dart"; | 
|  | import 'dart:collection' show Queue; | 
|  |  | 
|  | main() { | 
|  | Queue<int> queue1 = new Queue<int>(); | 
|  | queue1.add(42); | 
|  | Queue queue2 = new Queue(); | 
|  | queue2..add(11)..add(12)..add(13); | 
|  | Queue queue3 = new Queue(); | 
|  |  | 
|  | Expect.equals(42, queue1.single); | 
|  | Expect.throwsStateError(() => queue2.single); | 
|  | Expect.throwsStateError(() => queue3.single); | 
|  | } |