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
17package com.google.common.collect.testing.testers;
18
19import static com.google.common.collect.testing.features.CollectionFeature.SUPPORTS_CLEAR;
20import static com.google.common.collect.testing.features.CollectionSize.ZERO;
21
22import com.google.common.collect.testing.AbstractCollectionTester;
23import com.google.common.collect.testing.features.CollectionFeature;
24import com.google.common.collect.testing.features.CollectionSize;
25
26/**
27 * A generic JUnit test which tests {@code clear()} operations on a collection.
28 * Can't be invoked directly; please see
29 * {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
30 *
31 * <p>This class is GWT compatible.
32 *
33 * @author George van den Driessche
34 */
35public class CollectionClearTester<E> extends AbstractCollectionTester<E> {
36  @CollectionFeature.Require(SUPPORTS_CLEAR)
37  public void testClear() {
38    collection.clear();
39    assertTrue("After clear(), a collection should be empty.",
40        collection.isEmpty());
41  }
42
43  @CollectionFeature.Require(absent = SUPPORTS_CLEAR)
44  @CollectionSize.Require(absent = ZERO)
45  public void testClear_unsupported() {
46    try {
47      collection.clear();
48      fail("clear() should throw UnsupportedOperation if a collection does "
49          + "not support it and is not empty.");
50    } catch (UnsupportedOperationException expected) {
51    }
52    expectUnchanged();
53  }
54
55  @CollectionFeature.Require(absent = SUPPORTS_CLEAR)
56  @CollectionSize.Require(ZERO)
57  public void testClear_unsupportedByEmptyCollection() {
58    try {
59      collection.clear();
60    } catch (UnsupportedOperationException tolerated) {
61    }
62    expectUnchanged();
63  }
64}
65