ListSetTester.java revision 0888a09821a98ac0680fad765217302858e70fa4 
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.ALLOWS_NULL_VALUES;
20import static com.google.common.collect.testing.features.CollectionSize.ZERO;
21import static com.google.common.collect.testing.features.ListFeature.SUPPORTS_SET;
22
23import com.google.common.annotations.GwtCompatible;
24import com.google.common.annotations.GwtIncompatible;
25import com.google.common.collect.testing.Helpers;
26import com.google.common.collect.testing.features.CollectionFeature;
27import com.google.common.collect.testing.features.CollectionSize;
28import com.google.common.collect.testing.features.ListFeature;
29
30import java.lang.reflect.Method;
31
32/**
33 * A generic JUnit test which tests {@code set()} operations on a list. Can't be
34 * invoked directly; please see
35 * {@link com.google.common.collect.testing.ListTestSuiteBuilder}.
36 *
37 * @author George van den Driessche
38 */
39@GwtCompatible(emulated = true)
40public class ListSetTester<E> extends AbstractListTester<E> {
41  @ListFeature.Require(SUPPORTS_SET)
42  @CollectionSize.Require(absent = ZERO)
43  public void testSet() {
44    doTestSet(samples.e3);
45  }
46
47  @CollectionSize.Require(absent = ZERO)
48  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
49  @ListFeature.Require(SUPPORTS_SET)
50  public void testSet_null() {
51    doTestSet(null);
52  }
53
54  @CollectionSize.Require(absent = ZERO)
55  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
56  @ListFeature.Require(SUPPORTS_SET)
57  public void testSet_replacingNull() {
58    E[] elements = createSamplesArray();
59    int i = aValidIndex();
60    elements[i] = null;
61    collection = getSubjectGenerator().create(elements);
62
63    doTestSet(samples.e3);
64  }
65
66  private void doTestSet(E newValue) {
67    int index = aValidIndex();
68    E initialValue = getList().get(index);
69    assertEquals("set(i, x) should return the old element at position i.",
70        initialValue, getList().set(index, newValue));
71    assertEquals("After set(i, x), get(i) should return x",
72        newValue, getList().get(index));
73    assertEquals("set() should not change the size of a list.",
74        getNumElements(), getList().size());
75  }
76
77  @ListFeature.Require(SUPPORTS_SET)
78  public void testSet_indexTooLow() {
79    try {
80      getList().set(-1, samples.e3);
81      fail("set(-1) should throw IndexOutOfBoundsException");
82    } catch (IndexOutOfBoundsException expected) {
83    }
84    expectUnchanged();
85  }
86
87  @ListFeature.Require(SUPPORTS_SET)
88  public void testSet_indexTooHigh() {
89    int index = getNumElements();
90    try {
91      getList().set(index, samples.e3);
92      fail("set(size) should throw IndexOutOfBoundsException");
93    } catch (IndexOutOfBoundsException expected) {
94    }
95    expectUnchanged();
96  }
97
98  @CollectionSize.Require(absent = ZERO)
99  @ListFeature.Require(absent = SUPPORTS_SET)
100  public void testSet_unsupported() {
101    try {
102      getList().set(aValidIndex(), samples.e3);
103      fail("set() should throw UnsupportedOperationException");
104    } catch (UnsupportedOperationException expected) {
105    }
106    expectUnchanged();
107  }
108
109  @CollectionSize.Require(ZERO)
110  @ListFeature.Require(absent = SUPPORTS_SET)
111  public void testSet_unsupportedByEmptyList() {
112    try {
113      getList().set(0, samples.e3);
114      fail("set() should throw UnsupportedOperationException "
115          + "or IndexOutOfBoundsException");
116    } catch (UnsupportedOperationException tolerated) {
117    } catch (IndexOutOfBoundsException tolerated) {
118    }
119    expectUnchanged();
120  }
121
122  @CollectionSize.Require(absent = ZERO)
123  @ListFeature.Require(SUPPORTS_SET)
124  @CollectionFeature.Require(absent = ALLOWS_NULL_VALUES)
125  public void testSet_nullUnsupported() {
126    try {
127      getList().set(aValidIndex(), null);
128      fail("set(null) should throw NullPointerException");
129    } catch (NullPointerException expected) {
130    }
131    expectUnchanged();
132  }
133
134  private int aValidIndex() {
135    return getList().size() / 2;
136  }
137
138  /**
139   * Returns the {@link java.lang.reflect.Method} instance for
140   * {@link #testSet_null()} so that tests of {@link
141   * java.util.Collections#checkedCollection(java.util.Collection, Class)} can
142   * suppress it with {@code FeatureSpecificTestSuiteBuilder.suppressing()}
143   * until <a
144   * href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6409434">Sun bug
145   * 6409434</a> is fixed. It's unclear whether nulls were to be permitted or
146   * forbidden, but presumably the eventual fix will be to permit them, as it
147   * seems more likely that code would depend on that behavior than on the
148   * other. Thus, we say the bug is in set(), which fails to support null.
149   */
150  @GwtIncompatible("reflection")
151  public static Method getSetNullSupportedMethod() {
152    return Helpers.getMethod(ListSetTester.class, "testSet_null");
153  }
154}
155