guava

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/*
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 * Copyright (C) 2007 The Guava Authors
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 *
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 * Licensed under the Apache License, Version 2.0 (the "License");
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 * you may not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 * http://www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
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package com.google.common.collect.testing;
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import com.google.common.annotations.GwtCompatible;
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import com.google.errorprone.annotations.CanIgnoreReturnValue;
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import java.util.Collection;
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import org.checkerframework.checker.nullness.qual.Nullable;
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import org.junit.Ignore;
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/**
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 * Base class for collection testers.
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 *
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 * @param <E> the element type of the collection to be tested.
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 * @author Kevin Bourrillion
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 */
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@GwtCompatible
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@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
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@ElementTypesAreNonnullByDefault
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public abstract class AbstractCollectionTester<E extends @Nullable Object>
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    extends AbstractContainerTester<Collection<E>, E> {
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  // TODO: replace this with an accessor.
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  protected Collection<E> collection;
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  @Override
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  protected Collection<E> actualContents() {
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    return collection;
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  }
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  // TODO: dispose of this once collection is encapsulated.
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  @Override
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  @CanIgnoreReturnValue
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  protected Collection<E> resetContainer(Collection<E> newContents) {
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    collection = super.resetContainer(newContents);
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    return collection;
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  }
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  /** @see AbstractContainerTester#resetContainer() */
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  protected void resetCollection() {
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    resetContainer();
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  }
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  /** @return an array of the proper size with {@code null} inserted into the middle element. */
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  protected E[] createArrayWithNullElement() {
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    E[] array = createSamplesArray();
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    array[getNullLocation()] = null;
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    return array;
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  }
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  protected void initCollectionWithNullElement() {
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    E[] array = createArrayWithNullElement();
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    resetContainer(getSubjectGenerator().create(array));
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  }
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  /**
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   * Equivalent to {@link #expectMissing(Object[]) expectMissing}{@code (null)} except that the call
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   * to {@code contains(null)} is permitted to throw a {@code NullPointerException}.
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   *
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   * @param message message to use upon assertion failure
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   */
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  protected void expectNullMissingWhenNullUnsupported(String message) {
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    try {
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      assertFalse(message, actualContents().contains(null));
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    } catch (NullPointerException tolerated) {
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      // Tolerated
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    }
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  }
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}
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