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 
17 package com.google.common.collect.testing.testers;
18 
19 import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
20 import static com.google.common.collect.testing.features.CollectionSize.ZERO;
21 import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEYS;
22 import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEY_QUERIES;
23 import static com.google.common.collect.testing.features.MapFeature.FAILS_FAST_ON_CONCURRENT_MODIFICATION;
24 import static com.google.common.collect.testing.features.MapFeature.SUPPORTS_REMOVE;
25 
26 import com.google.common.annotations.GwtCompatible;
27 import com.google.common.collect.testing.AbstractMapTester;
28 import com.google.common.collect.testing.WrongType;
29 import com.google.common.collect.testing.features.CollectionSize;
30 import com.google.common.collect.testing.features.MapFeature;
31 
32 import java.util.ConcurrentModificationException;
33 import java.util.Iterator;
34 import java.util.Map.Entry;
35 
36 /**
37  * A generic JUnit test which tests {@code remove} operations on a map. Can't be
38  * invoked directly; please see
39  * {@link com.google.common.collect.testing.MapTestSuiteBuilder}.
40  *
41  * @author George van den Driessche
42  * @author Chris Povirk
43  */
44 @SuppressWarnings("unchecked") // too many "unchecked generic array creations"
45 @GwtCompatible
46 public class MapRemoveTester<K, V> extends AbstractMapTester<K, V> {
47   @MapFeature.Require(SUPPORTS_REMOVE)
48   @CollectionSize.Require(absent = ZERO)
testRemove_present()49   public void testRemove_present() {
50     int initialSize = getMap().size();
51     assertEquals("remove(present) should return the associated value",
52         samples.e0.getValue(), getMap().remove(samples.e0.getKey()));
53     assertEquals("remove(present) should decrease a map's size by one.",
54         initialSize - 1, getMap().size());
55     expectMissing(samples.e0);
56   }
57 
58   @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION,
59       SUPPORTS_REMOVE})
60   @CollectionSize.Require(SEVERAL)
testRemovePresentConcurrentWithEntrySetIteration()61   public void testRemovePresentConcurrentWithEntrySetIteration() {
62     try {
63       Iterator<Entry<K, V>> iterator = getMap().entrySet().iterator();
64       getMap().remove(samples.e0.getKey());
65       iterator.next();
66       fail("Expected ConcurrentModificationException");
67     } catch (ConcurrentModificationException expected) {
68       // success
69     }
70   }
71 
72   @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION,
73       SUPPORTS_REMOVE})
74   @CollectionSize.Require(SEVERAL)
testRemovePresentConcurrentWithKeySetIteration()75   public void testRemovePresentConcurrentWithKeySetIteration() {
76     try {
77       Iterator<K> iterator = getMap().keySet().iterator();
78       getMap().remove(samples.e0.getKey());
79       iterator.next();
80       fail("Expected ConcurrentModificationException");
81     } catch (ConcurrentModificationException expected) {
82       // success
83     }
84   }
85 
86   @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION,
87       SUPPORTS_REMOVE})
88   @CollectionSize.Require(SEVERAL)
testRemovePresentConcurrentWithValuesIteration()89   public void testRemovePresentConcurrentWithValuesIteration() {
90     try {
91       Iterator<V> iterator = getMap().values().iterator();
92       getMap().remove(samples.e0.getKey());
93       iterator.next();
94       fail("Expected ConcurrentModificationException");
95     } catch (ConcurrentModificationException expected) {
96       // success
97     }
98   }
99 
100   @MapFeature.Require(SUPPORTS_REMOVE)
testRemove_notPresent()101   public void testRemove_notPresent() {
102     assertNull("remove(notPresent) should return null",
103         getMap().remove(samples.e3.getKey()));
104     expectUnchanged();
105   }
106 
107   @MapFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_KEYS})
108   @CollectionSize.Require(absent = ZERO)
testRemove_nullPresent()109   public void testRemove_nullPresent() {
110     initMapWithNullKey();
111 
112     int initialSize = getMap().size();
113     assertEquals("remove(null) should return the associated value",
114         getValueForNullKey(), getMap().remove(null));
115     assertEquals("remove(present) should decrease a map's size by one.",
116         initialSize - 1, getMap().size());
117     expectMissing(entry(null, getValueForNullKey()));
118   }
119 
120   @MapFeature.Require(absent = SUPPORTS_REMOVE)
121   @CollectionSize.Require(absent = ZERO)
testRemove_unsupported()122   public void testRemove_unsupported() {
123     try {
124       getMap().remove(samples.e0.getKey());
125       fail("remove(present) should throw UnsupportedOperationException");
126     } catch (UnsupportedOperationException expected) {
127     }
128     expectUnchanged();
129     assertEquals("remove(present) should not remove the element",
130         samples.e0.getValue(), get(samples.e0.getKey()));
131   }
132 
133   @MapFeature.Require(absent = SUPPORTS_REMOVE)
testRemove_unsupportedNotPresent()134   public void testRemove_unsupportedNotPresent() {
135     try {
136       assertNull("remove(notPresent) should return null or throw "
137           + "UnsupportedOperationException",
138           getMap().remove(samples.e3.getKey()));
139     } catch (UnsupportedOperationException tolerated) {
140     }
141     expectUnchanged();
142     expectMissing(samples.e3);
143   }
144 
145   @MapFeature.Require(
146       value = SUPPORTS_REMOVE,
147       absent = ALLOWS_NULL_KEY_QUERIES)
testRemove_nullQueriesNotSupported()148   public void testRemove_nullQueriesNotSupported() {
149     try {
150       assertNull("remove(null) should return null or throw "
151           + "NullPointerException",
152           getMap().remove(null));
153     } catch (NullPointerException tolerated) {
154     }
155     expectUnchanged();
156   }
157 
158   @MapFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_KEY_QUERIES})
testRemove_nullSupportedMissing()159   public void testRemove_nullSupportedMissing() {
160     assertNull("remove(null) should return null", getMap().remove(null));
161     expectUnchanged();
162   }
163 
164   @MapFeature.Require(SUPPORTS_REMOVE)
testRemove_wrongType()165   public void testRemove_wrongType() {
166     try {
167       assertNull(getMap().remove(WrongType.VALUE));
168     } catch (ClassCastException tolerated) {
169     }
170     expectUnchanged();
171   }
172 }
173