QueuePeekTester.java revision 7dd252788645e940eada959bdde927426e2531c9 
1/*
2 * Copyright (C) 2008 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.common.collect.testing.testers;
18
19import static com.google.common.collect.testing.features.CollectionFeature.KNOWN_ORDER;
20import static com.google.common.collect.testing.features.CollectionSize.ONE;
21import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
22import static com.google.common.collect.testing.features.CollectionSize.ZERO;
23
24import com.google.common.annotations.GwtCompatible;
25import com.google.common.collect.testing.features.CollectionFeature;
26import com.google.common.collect.testing.features.CollectionSize;
27
28/**
29 * A generic JUnit test which tests {@code peek()} operations on a queue.
30 * Can't be invoked directly; please see
31 * {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
32 *
33 * <p>This class is GWT compatible.
34 *
35 * @author Jared Levy
36 */
37@GwtCompatible
38public class QueuePeekTester<E> extends AbstractQueueTester<E> {
39  @CollectionSize.Require(ZERO)
40  public void testPeek_empty() {
41    assertNull("emptyQueue.peek() should return null", getQueue().peek());
42    expectUnchanged();
43  }
44
45  @CollectionSize.Require(ONE)
46  public void testPeek_size1() {
47    assertEquals("size1Queue.peek() should return first element",
48        samples.e0, getQueue().peek());
49    expectUnchanged();
50  }
51
52  @CollectionFeature.Require(KNOWN_ORDER)
53  @CollectionSize.Require(SEVERAL)
54  public void testPeek_sizeMany() {
55    assertEquals("sizeManyQueue.peek() should return first element",
56        samples.e0, getQueue().peek());
57    expectUnchanged();
58  }
59}
60