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.checkerframework.checker.nullness.qual.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  /** @see AbstractContainerTester#resetContainer() */
057  protected void resetCollection() {
058    resetContainer();
059  }
060
061  /** @return an array of the proper size with {@code null} inserted into the middle element. */
062  protected E[] createArrayWithNullElement() {
063    E[] array = createSamplesArray();
064    array[getNullLocation()] = null;
065    return array;
066  }
067
068  protected void initCollectionWithNullElement() {
069    E[] array = createArrayWithNullElement();
070    resetContainer(getSubjectGenerator().create(array));
071  }
072
073  /**
074   * Equivalent to {@link #expectMissing(Object[]) expectMissing}{@code (null)} except that the call
075   * to {@code contains(null)} is permitted to throw a {@code NullPointerException}.
076   *
077   * @param message message to use upon assertion failure
078   */
079  protected void expectNullMissingWhenNullUnsupported(String message) {
080    try {
081      assertFalse(message, actualContents().contains(null));
082    } catch (NullPointerException tolerated) {
083      // Tolerated
084    }
085  }
086}