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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  import java.lang.reflect.Method;
30  import java.util.Arrays;
31  import java.util.Collection;
32  import java.util.List;
33  
34  /**
35   * A generic JUnit test which tests {@code toArray()} operations on a
36   * collection. Can't be invoked directly; please see
37   * {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
38   *
39   * @author Kevin Bourrillion
40   * @author Chris Povirk
41   */
42  @GwtCompatible(emulated = true)
43  public class CollectionToArrayTester<E> extends AbstractCollectionTester<E> {
44    public void testToArray_noArgs() {
45      Object[] array = collection.toArray();
46      expectArrayContentsAnyOrder(createSamplesArray(), array);
47    }
48  
49    /**
50     * {@link Collection#toArray(Object[])} says: "Note that
51     * <tt>toArray(new Object[0])</tt> is identical in function to
52     * <tt>toArray()</tt>."
53     *
54     * <p>For maximum effect, the collection under test should be created from an
55     * element array of a type other than {@code Object[]}.
56     */
57    public void testToArray_isPlainObjectArray() {
58      Object[] array = collection.toArray();
59      assertEquals(Object[].class, array.getClass());
60    }
61  
62    public void testToArray_emptyArray() {
63      E[] empty = getSubjectGenerator().createArray(0);
64      E[] array = collection.toArray(empty);
65      assertEquals(
66          "toArray(emptyT[]) should return an array of type T", empty.getClass(), array.getClass());
67      assertEquals("toArray(emptyT[]).length:", getNumElements(), array.length);
68      expectArrayContentsAnyOrder(createSamplesArray(), array);
69    }
70  
71    @CollectionFeature.Require(KNOWN_ORDER)
72    public void testToArray_emptyArray_ordered() {
73      E[] empty = getSubjectGenerator().createArray(0);
74      E[] array = collection.toArray(empty);
75      assertEquals(
76          "toArray(emptyT[]) should return an array of type T", empty.getClass(), array.getClass());
77      assertEquals("toArray(emptyT[]).length:", getNumElements(), array.length);
78      expectArrayContentsInOrder(getOrderedElements(), array);
79    }
80  
81    public void testToArray_emptyArrayOfObject() {
82      Object[] in = new Object[0];
83      Object[] array = collection.toArray(in);
84      assertEquals(
85          "toArray(emptyObject[]) should return an array of type Object",
86          Object[].class,
87          array.getClass());
88      assertEquals("toArray(emptyObject[]).length", getNumElements(), array.length);
89      expectArrayContentsAnyOrder(createSamplesArray(), array);
90    }
91  
92    public void testToArray_rightSizedArray() {
93      E[] array = getSubjectGenerator().createArray(getNumElements());
94      assertSame(
95          "toArray(sameSizeE[]) should return the given array", array, collection.toArray(array));
96      expectArrayContentsAnyOrder(createSamplesArray(), array);
97    }
98  
99    @CollectionFeature.Require(KNOWN_ORDER)
100   public void testToArray_rightSizedArray_ordered() {
101     E[] array = getSubjectGenerator().createArray(getNumElements());
102     assertSame(
103         "toArray(sameSizeE[]) should return the given array", array, collection.toArray(array));
104     expectArrayContentsInOrder(getOrderedElements(), array);
105   }
106 
107   public void testToArray_rightSizedArrayOfObject() {
108     Object[] array = new Object[getNumElements()];
109     assertSame(
110         "toArray(sameSizeObject[]) should return the given array",
111         array,
112         collection.toArray(array));
113     expectArrayContentsAnyOrder(createSamplesArray(), array);
114   }
115 
116   @CollectionFeature.Require(KNOWN_ORDER)
117   public void testToArray_rightSizedArrayOfObject_ordered() {
118     Object[] array = new Object[getNumElements()];
119     assertSame(
120         "toArray(sameSizeObject[]) should return the given array",
121         array,
122         collection.toArray(array));
123     expectArrayContentsInOrder(getOrderedElements(), array);
124   }
125 
126   public void testToArray_oversizedArray() {
127     E[] array = getSubjectGenerator().createArray(getNumElements() + 2);
128     array[getNumElements()] = e3();
129     array[getNumElements() + 1] = e3();
130     assertSame(
131         "toArray(overSizedE[]) should return the given array", array, collection.toArray(array));
132 
133     List<E> subArray = Arrays.asList(array).subList(0, getNumElements());
134     E[] expectedSubArray = createSamplesArray();
135     for (int i = 0; i < getNumElements(); i++) {
136       assertTrue(
137           "toArray(overSizedE[]) should contain element " + expectedSubArray[i],
138           subArray.contains(expectedSubArray[i]));
139     }
140     assertNull(
141         "The array element immediately following the end of the collection should be nulled",
142         array[getNumElements()]);
143     // array[getNumElements() + 1] might or might not have been nulled
144   }
145 
146   @CollectionFeature.Require(KNOWN_ORDER)
147   public void testToArray_oversizedArray_ordered() {
148     E[] array = getSubjectGenerator().createArray(getNumElements() + 2);
149     array[getNumElements()] = e3();
150     array[getNumElements() + 1] = e3();
151     assertSame(
152         "toArray(overSizedE[]) should return the given array", array, collection.toArray(array));
153 
154     List<E> expected = getOrderedElements();
155     for (int i = 0; i < getNumElements(); i++) {
156       assertEquals(expected.get(i), array[i]);
157     }
158     assertNull(
159         "The array element immediately following the end of the collection should be nulled",
160         array[getNumElements()]);
161     // array[getNumElements() + 1] might or might not have been nulled
162   }
163 
164   @CollectionSize.Require(absent = ZERO)
165   public void testToArray_emptyArrayOfWrongTypeForNonEmptyCollection() {
166     try {
167       WrongType[] array = new WrongType[0];
168       collection.toArray(array);
169       fail("toArray(notAssignableTo[]) should throw");
170     } catch (ArrayStoreException expected) {
171     }
172   }
173 
174   @CollectionSize.Require(ZERO)
175   public void testToArray_emptyArrayOfWrongTypeForEmptyCollection() {
176     WrongType[] array = new WrongType[0];
177     assertSame(
178         "toArray(sameSizeNotAssignableTo[]) should return the given array",
179         array,
180         collection.toArray(array));
181   }
182 
183   private void expectArrayContentsAnyOrder(Object[] expected, Object[] actual) {
184     Helpers.assertEqualIgnoringOrder(Arrays.asList(expected), Arrays.asList(actual));
185   }
186 
187   private void expectArrayContentsInOrder(List<E> expected, Object[] actual) {
188     assertEquals("toArray() ordered contents: ", expected, Arrays.asList(actual));
189   }
190 
191   /**
192    * Returns the {@link Method} instance for
193    * {@link #testToArray_isPlainObjectArray()} so that tests of
194    * {@link Arrays#asList(Object[])} can suppress it with {@code
195    * FeatureSpecificTestSuiteBuilder.suppressing()} until <a
196    * href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6260652">Sun bug
197    * 6260652</a> is fixed.
198    */
199   @GwtIncompatible // reflection
200   public static Method getToArrayIsPlainObjectArrayMethod() {
201     return Helpers.getMethod(CollectionToArrayTester.class, "testToArray_isPlainObjectArray");
202   }
203 }