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.ALLOWS_NULL_QUERIES;
020import static com.google.common.collect.testing.features.CollectionFeature.ALLOWS_NULL_VALUES;
021import static com.google.common.collect.testing.features.CollectionFeature.FAILS_FAST_ON_CONCURRENT_MODIFICATION;
022import static com.google.common.collect.testing.features.CollectionFeature.SUPPORTS_REMOVE;
023import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
024import static com.google.common.collect.testing.features.CollectionSize.ZERO;
025
026import com.google.common.annotations.GwtCompatible;
027import com.google.common.collect.testing.AbstractCollectionTester;
028import com.google.common.collect.testing.WrongType;
029import com.google.common.collect.testing.features.CollectionFeature;
030import com.google.common.collect.testing.features.CollectionSize;
031import java.util.ConcurrentModificationException;
032import java.util.Iterator;
033
034/**
035 * A generic JUnit test which tests {@code remove} operations on a collection. Can't be invoked
036 * directly; please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
037 *
038 * @author George van den Driessche
039 */
040@SuppressWarnings("unchecked") // too many "unchecked generic array creations"
041@GwtCompatible
042public class CollectionRemoveTester<E> extends AbstractCollectionTester<E> {
043  @CollectionFeature.Require(SUPPORTS_REMOVE)
044  @CollectionSize.Require(absent = ZERO)
045  public void testRemove_present() {
046    int initialSize = collection.size();
047    assertTrue("remove(present) should return true", collection.remove(e0()));
048    assertEquals(
049        "remove(present) should decrease a collection's size by one.",
050        initialSize - 1,
051        collection.size());
052    expectMissing(e0());
053  }
054
055  @CollectionFeature.Require({SUPPORTS_REMOVE, FAILS_FAST_ON_CONCURRENT_MODIFICATION})
056  @CollectionSize.Require(SEVERAL)
057  public void testRemovePresentConcurrentWithIteration() {
058    try {
059      Iterator<E> iterator = collection.iterator();
060      assertTrue(collection.remove(e0()));
061      iterator.next();
062      fail("Expected ConcurrentModificationException");
063    } catch (ConcurrentModificationException expected) {
064      // success
065    }
066  }
067
068  @CollectionFeature.Require(SUPPORTS_REMOVE)
069  public void testRemove_notPresent() {
070    assertFalse("remove(notPresent) should return false", collection.remove(e3()));
071    expectUnchanged();
072  }
073
074  @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
075  @CollectionSize.Require(absent = ZERO)
076  public void testRemove_nullPresent() {
077    collection = getSubjectGenerator().create(createArrayWithNullElement());
078
079    int initialSize = collection.size();
080    assertTrue("remove(null) should return true", collection.remove(null));
081    assertEquals(
082        "remove(present) should decrease a collection's size by one.",
083        initialSize - 1,
084        collection.size());
085    expectMissing((E) null);
086  }
087
088  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
089  @CollectionSize.Require(absent = ZERO)
090  public void testRemove_unsupported() {
091    try {
092      collection.remove(e0());
093      fail("remove(present) should throw UnsupportedOperationException");
094    } catch (UnsupportedOperationException expected) {
095    }
096    expectUnchanged();
097    assertTrue("remove(present) should not remove the element", collection.contains(e0()));
098  }
099
100  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
101  public void testRemove_unsupportedNotPresent() {
102    try {
103      assertFalse(
104          "remove(notPresent) should return false or throw UnsupportedOperationException",
105          collection.remove(e3()));
106    } catch (UnsupportedOperationException tolerated) {
107    }
108    expectUnchanged();
109    expectMissing(e3());
110  }
111
112  @CollectionFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_QUERIES)
113  public void testRemove_nullNotSupported() {
114    try {
115      assertFalse(
116          "remove(null) should return false or throw NullPointerException",
117          collection.remove(null));
118    } catch (NullPointerException tolerated) {
119    }
120    expectUnchanged();
121  }
122
123  @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_QUERIES})
124  public void testRemove_nullAllowed() {
125    assertFalse("remove(null) should return false", collection.remove(null));
126    expectUnchanged();
127  }
128
129  @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
130  @CollectionSize.Require(absent = ZERO)
131  public void testIteratorRemove_unsupported() {
132    Iterator<E> iterator = collection.iterator();
133    iterator.next();
134    try {
135      iterator.remove();
136      fail("iterator.remove() should throw UnsupportedOperationException");
137    } catch (UnsupportedOperationException expected) {
138    }
139    expectUnchanged();
140    assertTrue(collection.contains(e0()));
141  }
142
143  @CollectionFeature.Require(SUPPORTS_REMOVE)
144  public void testRemove_wrongType() {
145    try {
146      assertFalse(collection.remove(WrongType.VALUE));
147    } catch (ClassCastException tolerated) {
148    }
149    expectUnchanged();
150  }
151}