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;
018
019import com.google.common.annotations.GwtCompatible;
020import com.google.errorprone.annotations.CanIgnoreReturnValue;
021import java.util.Collection;
022import org.jspecify.annotations.NullMarked;
023import org.jspecify.annotations.Nullable;
024import org.junit.Ignore;
025
026/**
027 * Base class for collection testers.
028 *
029 * @param <E> the element type of the collection to be tested.
030 * @author Kevin Bourrillion
031 */
032@GwtCompatible
033@Ignore("test runners must not instantiate and run this directly, only via suites we build")
034// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
035@SuppressWarnings("JUnit4ClassUsedInJUnit3")
036@NullMarked
037public abstract class AbstractCollectionTester<E extends @Nullable Object>
038    extends AbstractContainerTester<Collection<E>, E> {
039
040  // TODO: replace this with an accessor.
041  protected Collection<E> collection;
042
043  @Override
044  protected Collection<E> actualContents() {
045    return collection;
046  }
047
048  // TODO: dispose of this once collection is encapsulated.
049  @Override
050  @CanIgnoreReturnValue
051  protected Collection<E> resetContainer(Collection<E> newContents) {
052    collection = super.resetContainer(newContents);
053    return collection;
054  }
055
056  /**
057   * @see AbstractContainerTester#resetContainer()
058   */
059  protected void resetCollection() {
060    resetContainer();
061  }
062
063  /**
064   * @return an array of the proper size with {@code null} inserted into the middle element.
065   */
066  protected E[] createArrayWithNullElement() {
067    E[] array = createSamplesArray();
068    array[getNullLocation()] = null;
069    return array;
070  }
071
072  protected void initCollectionWithNullElement() {
073    E[] array = createArrayWithNullElement();
074    resetContainer(getSubjectGenerator().create(array));
075  }
076
077  /**
078   * Equivalent to {@link #expectMissing(Object[]) expectMissing}{@code (null)} except that the call
079   * to {@code contains(null)} is permitted to throw a {@code NullPointerException}.
080   *
081   * @param message message to use upon assertion failure
082   */
083  protected void expectNullMissingWhenNullUnsupported(String message) {
084    try {
085      assertFalse(message, actualContents().contains(null));
086    } catch (NullPointerException tolerated) {
087      // Tolerated
088    }
089  }
090}