Java

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/*
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 * Copyright (C) 2008 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.testers;
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import static com.google.common.collect.testing.Helpers.mapEntry;
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import static com.google.common.collect.testing.IteratorFeature.MODIFIABLE;
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import static com.google.common.collect.testing.IteratorFeature.UNMODIFIABLE;
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import static com.google.common.collect.testing.features.CollectionFeature.ALLOWS_NULL_VALUES;
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import static com.google.common.collect.testing.features.CollectionFeature.KNOWN_ORDER;
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import static com.google.common.collect.testing.features.CollectionFeature.SUPPORTS_ITERATOR_REMOVE;
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import static com.google.common.collect.testing.features.CollectionSize.ZERO;
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import static java.util.Arrays.asList;
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import com.google.common.annotations.GwtCompatible;
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import com.google.common.collect.testing.AbstractCollectionTester;
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import com.google.common.collect.testing.Helpers;
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import com.google.common.collect.testing.IteratorFeature;
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import com.google.common.collect.testing.IteratorTester;
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import com.google.common.collect.testing.features.CollectionFeature;
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import com.google.common.collect.testing.features.CollectionSize;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.Iterator;
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import java.util.List;
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import java.util.Map.Entry;
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import java.util.NoSuchElementException;
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import java.util.Set;
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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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 * A generic JUnit test which tests {@code iterator} operations on a collection. Can't be invoked
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 * directly; please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
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 *
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 * @author Chris Povirk
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 */
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@GwtCompatible(emulated = true)
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@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
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@SuppressWarnings("JUnit4ClassUsedInJUnit3")
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@ElementTypesAreNonnullByDefault
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public class CollectionIteratorTester<E extends @Nullable Object>
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    extends AbstractCollectionTester<E> {
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  public void testIterator() {
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    List<E> iteratorElements = new ArrayList<>();
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    for (E element : collection) { // uses iterator()
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      iteratorElements.add(element);
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    }
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    Helpers.assertEqualIgnoringOrder(Arrays.asList(createSamplesArray()), iteratorElements);
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  }
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  @CollectionFeature.Require(KNOWN_ORDER)
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  public void testIterationOrdering() {
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    List<E> iteratorElements = new ArrayList<>();
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    for (E element : collection) { // uses iterator()
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      iteratorElements.add(element);
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    }
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    List<E> expected = Helpers.copyToList(getOrderedElements());
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    assertEquals("Different ordered iteration", expected, iteratorElements);
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  }
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  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
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  @CollectionSize.Require(absent = ZERO)
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  public void testIterator_nullElement() {
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    initCollectionWithNullElement();
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    List<E> iteratorElements = new ArrayList<>();
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    for (E element : collection) { // uses iterator()
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      iteratorElements.add(element);
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    }
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    Helpers.assertEqualIgnoringOrder(asList(createArrayWithNullElement()), iteratorElements);
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  }
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  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)
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  @CollectionSize.Require(absent = ZERO)
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  public void testIterator_removeAffectsBackingCollection() {
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    int originalSize = collection.size();
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    Iterator<E> iterator = collection.iterator();
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    Object element = iterator.next();
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    // If it's an Entry, it may become invalid once it's removed from the Map. Copy it.
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    if (element instanceof Entry) {
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      Entry<?, ?> entry = (Entry<?, ?>) element;
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      element = mapEntry(entry.getKey(), entry.getValue());
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    }
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    assertTrue(collection.contains(element)); // sanity check
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    iterator.remove();
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    assertFalse(collection.contains(element));
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    assertEquals(originalSize - 1, collection.size());
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  }
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  @CollectionFeature.Require({KNOWN_ORDER, SUPPORTS_ITERATOR_REMOVE})
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  public void testIterator_knownOrderRemoveSupported() {
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    runIteratorTest(MODIFIABLE, IteratorTester.KnownOrder.KNOWN_ORDER, getOrderedElements());
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  }
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  @CollectionFeature.Require(value = KNOWN_ORDER, absent = SUPPORTS_ITERATOR_REMOVE)
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  public void testIterator_knownOrderRemoveUnsupported() {
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    runIteratorTest(UNMODIFIABLE, IteratorTester.KnownOrder.KNOWN_ORDER, getOrderedElements());
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  }
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  @CollectionFeature.Require(absent = KNOWN_ORDER, value = SUPPORTS_ITERATOR_REMOVE)
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  public void testIterator_unknownOrderRemoveSupported() {
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    runIteratorTest(MODIFIABLE, IteratorTester.KnownOrder.UNKNOWN_ORDER, getSampleElements());
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  }
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  @CollectionFeature.Require(absent = {KNOWN_ORDER, SUPPORTS_ITERATOR_REMOVE})
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  public void testIterator_unknownOrderRemoveUnsupported() {
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    runIteratorTest(UNMODIFIABLE, IteratorTester.KnownOrder.UNKNOWN_ORDER, getSampleElements());
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  }
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  private void runIteratorTest(
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      Set<IteratorFeature> features, IteratorTester.KnownOrder knownOrder, Iterable<E> elements) {
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    new IteratorTester<E>(
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        Platform.collectionIteratorTesterNumIterations(), features, elements, knownOrder) {
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      @Override
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      protected Iterator<E> newTargetIterator() {
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        resetCollection();
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        return collection.iterator();
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      }
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      @Override
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      protected void verify(List<E> elements) {
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        expectContents(elements);
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      }
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    }.test();
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  }
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  public void testIteratorNoSuchElementException() {
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    Iterator<E> iterator = collection.iterator();
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    while (iterator.hasNext()) {
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      iterator.next();
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    }
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    try {
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      iterator.next();
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      fail("iterator.next() should throw NoSuchElementException");
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    } catch (NoSuchElementException expected) {
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    }
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  }
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}
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