1 /*
2  * Copyright (C) 2007 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.KNOWN_ORDER;
20 import static com.google.common.collect.testing.features.CollectionSize.ZERO;
21 
22 import com.google.common.annotations.GwtCompatible;
23 import com.google.common.annotations.GwtIncompatible;
24 import com.google.common.collect.testing.AbstractCollectionTester;
25 import com.google.common.collect.testing.Helpers;
26 import com.google.common.collect.testing.WrongType;
27 import com.google.common.collect.testing.features.CollectionFeature;
28 import com.google.common.collect.testing.features.CollectionSize;
29 
30 import java.lang.reflect.Method;
31 import java.util.Arrays;
32 import java.util.Collection;
33 import java.util.List;
34 
35 /**
36  * A generic JUnit test which tests {@code toArray()} operations on a
37  * collection. Can't be invoked directly; please see
38  * {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
39  *
40  * @author Kevin Bourrillion
41  * @author Chris Povirk
42  */
43 @GwtCompatible(emulated = true)
44 public class CollectionToArrayTester<E> extends AbstractCollectionTester<E> {
testToArray_noArgs()45   public void testToArray_noArgs() {
46     Object[] array = collection.toArray();
47     expectArrayContentsAnyOrder(createSamplesArray(), array);
48   }
49 
50   /**
51    * {@link Collection#toArray(Object[])} says: "Note that
52    * <tt>toArray(new Object[0])</tt> is identical in function to
53    * <tt>toArray()</tt>."
54    *
55    * <p>For maximum effect, the collection under test should be created from an
56    * element array of a type other than {@code Object[]}.
57    */
testToArray_isPlainObjectArray()58   public void testToArray_isPlainObjectArray() {
59     Object[] array = collection.toArray();
60     assertEquals(Object[].class, array.getClass());
61   }
62 
testToArray_emptyArray()63   public void testToArray_emptyArray() {
64     E[] empty = getSubjectGenerator().createArray(0);
65     E[] array = collection.toArray(empty);
66     assertEquals("toArray(emptyT[]) should return an array of type T",
67         empty.getClass(), array.getClass());
68     assertEquals("toArray(emptyT[]).length:", getNumElements(), array.length);
69     expectArrayContentsAnyOrder(createSamplesArray(), array);
70   }
71 
72   @CollectionFeature.Require(KNOWN_ORDER)
testToArray_emptyArray_ordered()73   public void testToArray_emptyArray_ordered() {
74     E[] empty = getSubjectGenerator().createArray(0);
75     E[] array = collection.toArray(empty);
76     assertEquals("toArray(emptyT[]) should return an array of type T",
77         empty.getClass(), array.getClass());
78     assertEquals("toArray(emptyT[]).length:", getNumElements(), array.length);
79     expectArrayContentsInOrder(getOrderedElements(), array);
80   }
81 
testToArray_emptyArrayOfObject()82   public void testToArray_emptyArrayOfObject() {
83     Object[] in = new Object[0];
84     Object[] array = collection.toArray(in);
85     assertEquals("toArray(emptyObject[]) should return an array of type Object",
86         Object[].class, array.getClass());
87     assertEquals("toArray(emptyObject[]).length",
88         getNumElements(), array.length);
89     expectArrayContentsAnyOrder(createSamplesArray(), array);
90   }
91 
testToArray_rightSizedArray()92   public void testToArray_rightSizedArray() {
93     E[] array = getSubjectGenerator().createArray(getNumElements());
94     assertSame("toArray(sameSizeE[]) should return the given array",
95         array, collection.toArray(array));
96     expectArrayContentsAnyOrder(createSamplesArray(), array);
97   }
98 
99   @CollectionFeature.Require(KNOWN_ORDER)
testToArray_rightSizedArray_ordered()100   public void testToArray_rightSizedArray_ordered() {
101     E[] array = getSubjectGenerator().createArray(getNumElements());
102     assertSame("toArray(sameSizeE[]) should return the given array",
103         array, collection.toArray(array));
104     expectArrayContentsInOrder(getOrderedElements(), array);
105   }
106 
testToArray_rightSizedArrayOfObject()107   public void testToArray_rightSizedArrayOfObject() {
108     Object[] array = new Object[getNumElements()];
109     assertSame("toArray(sameSizeObject[]) should return the given array",
110         array, collection.toArray(array));
111     expectArrayContentsAnyOrder(createSamplesArray(), array);
112   }
113 
114   @CollectionFeature.Require(KNOWN_ORDER)
testToArray_rightSizedArrayOfObject_ordered()115   public void testToArray_rightSizedArrayOfObject_ordered() {
116     Object[] array = new Object[getNumElements()];
117     assertSame("toArray(sameSizeObject[]) should return the given array",
118         array, collection.toArray(array));
119     expectArrayContentsInOrder(getOrderedElements(), array);
120   }
121 
testToArray_oversizedArray()122   public void testToArray_oversizedArray() {
123     E[] array = getSubjectGenerator().createArray(getNumElements() + 2);
124     array[getNumElements()] = samples.e3;
125     array[getNumElements() + 1] = samples.e3;
126     assertSame("toArray(overSizedE[]) should return the given array",
127         array, collection.toArray(array));
128 
129     List<E> subArray = Arrays.asList(array).subList(0, getNumElements());
130     E[] expectedSubArray = createSamplesArray();
131     for (int i = 0; i < getNumElements(); i++) {
132       assertTrue(
133           "toArray(overSizedE[]) should contain element " + expectedSubArray[i],
134           subArray.contains(expectedSubArray[i]));
135     }
136     assertNull("The array element "
137         + "immediately following the end of the collection should be nulled",
138         array[getNumElements()]);
139     // array[getNumElements() + 1] might or might not have been nulled
140   }
141 
142   @CollectionFeature.Require(KNOWN_ORDER)
testToArray_oversizedArray_ordered()143   public void testToArray_oversizedArray_ordered() {
144     E[] array = getSubjectGenerator().createArray(getNumElements() + 2);
145     array[getNumElements()] = samples.e3;
146     array[getNumElements() + 1] = samples.e3;
147     assertSame("toArray(overSizedE[]) should return the given array",
148         array, collection.toArray(array));
149 
150     List<E> expected = getOrderedElements();
151     for (int i = 0; i < getNumElements(); i++) {
152       assertEquals(expected.get(i), array[i]);
153     }
154     assertNull("The array element "
155         + "immediately following the end of the collection should be nulled",
156         array[getNumElements()]);
157     // array[getNumElements() + 1] might or might not have been nulled
158   }
159 
160   @CollectionSize.Require(absent = ZERO)
testToArray_emptyArrayOfWrongTypeForNonEmptyCollection()161   public void testToArray_emptyArrayOfWrongTypeForNonEmptyCollection() {
162     try {
163       WrongType[] array = new WrongType[0];
164       collection.toArray(array);
165       fail("toArray(notAssignableTo[]) should throw");
166     } catch (ArrayStoreException expected) {
167     }
168   }
169 
170   @CollectionSize.Require(ZERO)
testToArray_emptyArrayOfWrongTypeForEmptyCollection()171   public void testToArray_emptyArrayOfWrongTypeForEmptyCollection() {
172     WrongType[] array = new WrongType[0];
173     assertSame(
174         "toArray(sameSizeNotAssignableTo[]) should return the given array",
175         array, collection.toArray(array));
176   }
177 
expectArrayContentsAnyOrder(Object[] expected, Object[] actual)178   private void expectArrayContentsAnyOrder(Object[] expected, Object[] actual) {
179     Helpers.assertEqualIgnoringOrder(
180         Arrays.asList(expected), Arrays.asList(actual));
181   }
182 
expectArrayContentsInOrder(List<E> expected, Object[] actual)183   private void expectArrayContentsInOrder(List<E> expected, Object[] actual) {
184     assertEquals("toArray() ordered contents: ",
185         expected, Arrays.asList(actual));
186   }
187 
188   /**
189    * Returns the {@link Method} instance for
190    * {@link #testToArray_isPlainObjectArray()} so that tests of
191    * {@link Arrays#asList(Object[])} can suppress it with {@code
192    * FeatureSpecificTestSuiteBuilder.suppressing()} until <a
193    * href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6260652">Sun bug
194    * 6260652</a> is fixed.
195    */
196   @GwtIncompatible("reflection")
getToArrayIsPlainObjectArrayMethod()197   public static Method getToArrayIsPlainObjectArrayMethod() {
198     return Helpers.getMethod(CollectionToArrayTester.class, "testToArray_isPlainObjectArray");
199   }
200 }
201