001/* 002 * Copyright (C) 2008 The Guava Authors 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package com.google.common.collect.testing.testers; 018 019import static com.google.common.collect.testing.features.CollectionFeature.KNOWN_ORDER; 020import static com.google.common.collect.testing.features.CollectionSize.ONE; 021import static com.google.common.collect.testing.features.CollectionSize.SEVERAL; 022import static com.google.common.collect.testing.features.CollectionSize.ZERO; 023 024import com.google.common.annotations.GwtCompatible; 025import com.google.common.collect.testing.features.CollectionFeature; 026import com.google.common.collect.testing.features.CollectionSize; 027 028/** 029 * A generic JUnit test which tests {@code peek()} operations on a queue. Can't be invoked directly; 030 * please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}. 031 * 032 * @author Jared Levy 033 */ 034@GwtCompatible 035public class QueuePeekTester<E> extends AbstractQueueTester<E> { 036 @CollectionSize.Require(ZERO) 037 public void testPeek_empty() { 038 assertNull("emptyQueue.peek() should return null", getQueue().peek()); 039 expectUnchanged(); 040 } 041 042 @CollectionSize.Require(ONE) 043 public void testPeek_size1() { 044 assertEquals("size1Queue.peek() should return first element", e0(), getQueue().peek()); 045 expectUnchanged(); 046 } 047 048 @CollectionFeature.Require(KNOWN_ORDER) 049 @CollectionSize.Require(SEVERAL) 050 public void testPeek_sizeMany() { 051 assertEquals("sizeManyQueue.peek() should return first element", e0(), getQueue().peek()); 052 expectUnchanged(); 053 } 054}