Coverage Summary for Class: CollectionClearTester (com.google.common.collect.testing.testers)

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.CollectionFeature.FAILS_FAST_ON_CONCURRENT_MODIFICATION;
20 import static com.google.common.collect.testing.features.CollectionFeature.SUPPORTS_REMOVE;
21 import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
22 import static com.google.common.collect.testing.features.CollectionSize.ZERO;
23 
24 import com.google.common.annotations.GwtCompatible;
25 import com.google.common.collect.testing.AbstractCollectionTester;
26 import com.google.common.collect.testing.features.CollectionFeature;
27 import com.google.common.collect.testing.features.CollectionSize;
28 import java.util.ConcurrentModificationException;
29 import java.util.Iterator;
30 import org.junit.Ignore;
31 
32 /**
33  * A generic JUnit test which tests {@code clear()} operations on a collection. Can't be invoked
34  * directly; please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
35  *
36  * @author George van den Driessche
37  */
38 @GwtCompatible
39 @Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
40 public class CollectionClearTester<E> extends AbstractCollectionTester<E> {
41   @CollectionFeature.Require(SUPPORTS_REMOVE)
42   public void testClear() {
43     collection.clear();
44     assertTrue("After clear(), a collection should be empty.", collection.isEmpty());
45     assertEquals(0, collection.size());
46     assertFalse(collection.iterator().hasNext());
47   }
48 
49   @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
50   @CollectionSize.Require(absent = ZERO)
51   public void testClear_unsupported() {
52     try {
53       collection.clear();
54       fail(
55           "clear() should throw UnsupportedOperation if a collection does "
56               + "not support it and is not empty.");
57     } catch (UnsupportedOperationException expected) {
58     }
59     expectUnchanged();
60   }
61 
62   @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
63   @CollectionSize.Require(ZERO)
64   public void testClear_unsupportedByEmptyCollection() {
65     try {
66       collection.clear();
67     } catch (UnsupportedOperationException tolerated) {
68     }
69     expectUnchanged();
70   }
71 
72   @CollectionFeature.Require({SUPPORTS_REMOVE, FAILS_FAST_ON_CONCURRENT_MODIFICATION})
73   @CollectionSize.Require(SEVERAL)
74   public void testClearConcurrentWithIteration() {
75     try {
76       Iterator<E> iterator = collection.iterator();
77       collection.clear();
78       iterator.next();
79       /*
80        * We prefer for iterators to fail immediately on hasNext, but ArrayList
81        * and LinkedList will notably return true on hasNext here!
82        */
83       fail("Expected ConcurrentModificationException");
84     } catch (ConcurrentModificationException expected) {
85       // success
86     }
87   }
88 }