001/*
002 * Copyright (C) 2007 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.common.collect.testing.testers;
018
019import static com.google.common.collect.testing.Helpers.assertEqualIgnoringOrder;
020import static com.google.common.collect.testing.Helpers.getMethod;
021import static com.google.common.collect.testing.features.CollectionFeature.KNOWN_ORDER;
022import static com.google.common.collect.testing.features.CollectionSize.ZERO;
023import static java.util.Arrays.asList;
024import static org.junit.Assert.assertThrows;
025
026import com.google.common.annotations.GwtCompatible;
027import com.google.common.annotations.GwtIncompatible;
028import com.google.common.annotations.J2ktIncompatible;
029import com.google.common.collect.testing.AbstractCollectionTester;
030import com.google.common.collect.testing.WrongType;
031import com.google.common.collect.testing.features.CollectionFeature;
032import com.google.common.collect.testing.features.CollectionSize;
033import java.lang.reflect.Method;
034import java.util.Arrays;
035import java.util.Collection;
036import java.util.List;
037
038/**
039 * A generic JUnit test which tests {@code toArray()} operations on a collection. Can't be invoked
040 * directly; please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
041 *
042 * @author Kevin Bourrillion
043 * @author Chris Povirk
044 */
045@GwtCompatible
046public class CollectionToArrayTester<E> extends AbstractCollectionTester<E> {
047  public void testToArray_noArgs() {
048    Object[] array = collection.toArray();
049    expectArrayContentsAnyOrder(createSamplesArray(), array);
050  }
051
052  /**
053   * {@link Collection#toArray(Object[])} says: "Note that {@code toArray(new Object[0])} is
054   * identical in function to {@code toArray()}."
055   *
056   * <p>For maximum effect, the collection under test should be created from an element array of a
057   * type other than {@code Object[]}.
058   */
059  public void testToArray_isPlainObjectArray() {
060    Object[] array = collection.toArray();
061    assertEquals(Object[].class, array.getClass());
062  }
063
064  public void testToArray_emptyArray() {
065    E[] empty = getSubjectGenerator().createArray(0);
066    E[] array = collection.toArray(empty);
067    assertEquals(
068        "toArray(emptyT[]) should return an array of type T", empty.getClass(), array.getClass());
069    assertEquals("toArray(emptyT[]).length:", getNumElements(), array.length);
070    expectArrayContentsAnyOrder(createSamplesArray(), array);
071  }
072
073  @CollectionFeature.Require(KNOWN_ORDER)
074  public void testToArray_emptyArray_ordered() {
075    E[] empty = getSubjectGenerator().createArray(0);
076    E[] array = collection.toArray(empty);
077    assertEquals(
078        "toArray(emptyT[]) should return an array of type T", empty.getClass(), array.getClass());
079    assertEquals("toArray(emptyT[]).length:", getNumElements(), array.length);
080    expectArrayContentsInOrder(getOrderedElements(), array);
081  }
082
083  public void testToArray_emptyArrayOfObject() {
084    Object[] in = new Object[0];
085    Object[] array = collection.toArray(in);
086    assertEquals(
087        "toArray(emptyObject[]) should return an array of type Object",
088        Object[].class,
089        array.getClass());
090    assertEquals("toArray(emptyObject[]).length", getNumElements(), array.length);
091    expectArrayContentsAnyOrder(createSamplesArray(), array);
092  }
093
094  public void testToArray_rightSizedArray() {
095    E[] array = getSubjectGenerator().createArray(getNumElements());
096    assertSame(
097        "toArray(sameSizeE[]) should return the given array", array, collection.toArray(array));
098    expectArrayContentsAnyOrder(createSamplesArray(), array);
099  }
100
101  @CollectionFeature.Require(KNOWN_ORDER)
102  public void testToArray_rightSizedArray_ordered() {
103    E[] array = getSubjectGenerator().createArray(getNumElements());
104    assertSame(
105        "toArray(sameSizeE[]) should return the given array", array, collection.toArray(array));
106    expectArrayContentsInOrder(getOrderedElements(), array);
107  }
108
109  public void testToArray_rightSizedArrayOfObject() {
110    Object[] array = new Object[getNumElements()];
111    assertSame(
112        "toArray(sameSizeObject[]) should return the given array",
113        array,
114        collection.toArray(array));
115    expectArrayContentsAnyOrder(createSamplesArray(), array);
116  }
117
118  @CollectionFeature.Require(KNOWN_ORDER)
119  public void testToArray_rightSizedArrayOfObject_ordered() {
120    Object[] array = new Object[getNumElements()];
121    assertSame(
122        "toArray(sameSizeObject[]) should return the given array",
123        array,
124        collection.toArray(array));
125    expectArrayContentsInOrder(getOrderedElements(), array);
126  }
127
128  public void testToArray_oversizedArray() {
129    E[] array = getSubjectGenerator().createArray(getNumElements() + 2);
130    array[getNumElements()] = e3();
131    array[getNumElements() + 1] = e3();
132    assertSame(
133        "toArray(overSizedE[]) should return the given array", array, collection.toArray(array));
134
135    List<E> subArray = asList(array).subList(0, getNumElements());
136    E[] expectedSubArray = createSamplesArray();
137    for (int i = 0; i < getNumElements(); i++) {
138      assertTrue(
139          "toArray(overSizedE[]) should contain element " + expectedSubArray[i],
140          subArray.contains(expectedSubArray[i]));
141    }
142    assertNull(
143        "The array element immediately following the end of the collection should be nulled",
144        array[getNumElements()]);
145    // array[getNumElements() + 1] might or might not have been nulled
146  }
147
148  @CollectionFeature.Require(KNOWN_ORDER)
149  public void testToArray_oversizedArray_ordered() {
150    E[] array = getSubjectGenerator().createArray(getNumElements() + 2);
151    array[getNumElements()] = e3();
152    array[getNumElements() + 1] = e3();
153    assertSame(
154        "toArray(overSizedE[]) should return the given array", array, collection.toArray(array));
155
156    List<E> expected = getOrderedElements();
157    for (int i = 0; i < getNumElements(); i++) {
158      assertEquals(expected.get(i), array[i]);
159    }
160    assertNull(
161        "The array element immediately following the end of the collection should be nulled",
162        array[getNumElements()]);
163    // array[getNumElements() + 1] might or might not have been nulled
164  }
165
166  @CollectionSize.Require(absent = ZERO)
167  public void testToArray_emptyArrayOfWrongTypeForNonEmptyCollection() {
168    WrongType[] array = new WrongType[0];
169    assertThrows(ArrayStoreException.class, () -> collection.toArray(array));
170  }
171
172  @CollectionSize.Require(ZERO)
173  public void testToArray_emptyArrayOfWrongTypeForEmptyCollection() {
174    WrongType[] array = new WrongType[0];
175    assertSame(
176        "toArray(sameSizeNotAssignableTo[]) should return the given array",
177        array,
178        collection.toArray(array));
179  }
180
181  private static void expectArrayContentsAnyOrder(Object[] expected, Object[] actual) {
182    assertEqualIgnoringOrder(asList(expected), asList(actual));
183  }
184
185  private void expectArrayContentsInOrder(List<E> expected, Object[] actual) {
186    assertEquals("toArray() ordered contents: ", expected, asList(actual));
187  }
188
189  /**
190   * Returns the {@link Method} instance for {@link #testToArray_isPlainObjectArray()} so that tests
191   * of {@link Arrays#asList(Object[])} can suppress it with {@code
192   * FeatureSpecificTestSuiteBuilder.suppressing()} until <a
193   * href="https://bugs.openjdk.org/browse/JDK-6260652">JDK-6260652</a> is fixed.
194   */
195  @J2ktIncompatible
196  @GwtIncompatible // reflection
197  public static Method getToArrayIsPlainObjectArrayMethod() {
198    return getMethod(CollectionToArrayTester.class, "testToArray_isPlainObjectArray");
199  }
200}