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;
023import static org.junit.Assert.assertThrows;
024
025import com.google.common.annotations.GwtCompatible;
026import com.google.common.collect.testing.features.CollectionFeature;
027import com.google.common.collect.testing.features.CollectionSize;
028import java.util.NoSuchElementException;
029
030/**
031 * A generic JUnit test which tests {@code element()} operations on a queue. Can't be invoked
032 * directly; please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
033 *
034 * @author Jared Levy
035 */
036@GwtCompatible
037public class QueueElementTester<E> extends AbstractQueueTester<E> {
038  @CollectionSize.Require(ZERO)
039  public void testElement_empty() {
040    assertThrows(NoSuchElementException.class, () -> getQueue().element());
041    expectUnchanged();
042  }
043
044  @CollectionSize.Require(ONE)
045  public void testElement_size1() {
046    assertEquals("size1Queue.element() should return first element", e0(), getQueue().element());
047    expectUnchanged();
048  }
049
050  @CollectionFeature.Require(KNOWN_ORDER)
051  @CollectionSize.Require(SEVERAL)
052  public void testElement_sizeMany() {
053    assertEquals("sizeManyQueue.element() should return first element", e0(), getQueue().element());
054    expectUnchanged();
055  }
056}