001/*
002 * Copyright (C) 2008 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.mapEntry;
020import static com.google.common.collect.testing.IteratorFeature.MODIFIABLE;
021import static com.google.common.collect.testing.IteratorFeature.UNMODIFIABLE;
022import static com.google.common.collect.testing.features.CollectionFeature.ALLOWS_NULL_VALUES;
023import static com.google.common.collect.testing.features.CollectionFeature.KNOWN_ORDER;
024import static com.google.common.collect.testing.features.CollectionFeature.SUPPORTS_ITERATOR_REMOVE;
025import static com.google.common.collect.testing.features.CollectionSize.ZERO;
026import static java.util.Arrays.asList;
027
028import com.google.common.annotations.GwtCompatible;
029import com.google.common.collect.testing.AbstractCollectionTester;
030import com.google.common.collect.testing.Helpers;
031import com.google.common.collect.testing.IteratorFeature;
032import com.google.common.collect.testing.IteratorTester;
033import com.google.common.collect.testing.features.CollectionFeature;
034import com.google.common.collect.testing.features.CollectionSize;
035import java.util.ArrayList;
036import java.util.Arrays;
037import java.util.Iterator;
038import java.util.List;
039import java.util.Map.Entry;
040import java.util.NoSuchElementException;
041import java.util.Set;
042import org.checkerframework.checker.nullness.qual.Nullable;
043import org.junit.Ignore;
044
045/**
046 * A generic JUnit test which tests {@code iterator} operations on a collection. Can't be invoked
047 * directly; please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
048 *
049 * @author Chris Povirk
050 */
051@GwtCompatible(emulated = true)
052@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
053@ElementTypesAreNonnullByDefault
054public class CollectionIteratorTester<E extends @Nullable Object>
055    extends AbstractCollectionTester<E> {
056  public void testIterator() {
057    List<E> iteratorElements = new ArrayList<>();
058    for (E element : collection) { // uses iterator()
059      iteratorElements.add(element);
060    }
061    Helpers.assertEqualIgnoringOrder(Arrays.asList(createSamplesArray()), iteratorElements);
062  }
063
064  @CollectionFeature.Require(KNOWN_ORDER)
065  public void testIterationOrdering() {
066    List<E> iteratorElements = new ArrayList<>();
067    for (E element : collection) { // uses iterator()
068      iteratorElements.add(element);
069    }
070    List<E> expected = Helpers.copyToList(getOrderedElements());
071    assertEquals("Different ordered iteration", expected, iteratorElements);
072  }
073
074  @CollectionFeature.Require(ALLOWS_NULL_VALUES)
075  @CollectionSize.Require(absent = ZERO)
076  public void testIterator_nullElement() {
077    initCollectionWithNullElement();
078    List<E> iteratorElements = new ArrayList<>();
079    for (E element : collection) { // uses iterator()
080      iteratorElements.add(element);
081    }
082    Helpers.assertEqualIgnoringOrder(asList(createArrayWithNullElement()), iteratorElements);
083  }
084
085  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)
086  @CollectionSize.Require(absent = ZERO)
087  public void testIterator_removeAffectsBackingCollection() {
088    int originalSize = collection.size();
089    Iterator<E> iterator = collection.iterator();
090    Object element = iterator.next();
091    // If it's an Entry, it may become invalid once it's removed from the Map. Copy it.
092    if (element instanceof Entry) {
093      Entry<?, ?> entry = (Entry<?, ?>) element;
094      element = mapEntry(entry.getKey(), entry.getValue());
095    }
096    assertTrue(collection.contains(element)); // sanity check
097    iterator.remove();
098    assertFalse(collection.contains(element));
099    assertEquals(originalSize - 1, collection.size());
100  }
101
102  @CollectionFeature.Require({KNOWN_ORDER, SUPPORTS_ITERATOR_REMOVE})
103  public void testIterator_knownOrderRemoveSupported() {
104    runIteratorTest(MODIFIABLE, IteratorTester.KnownOrder.KNOWN_ORDER, getOrderedElements());
105  }
106
107  @CollectionFeature.Require(value = KNOWN_ORDER, absent = SUPPORTS_ITERATOR_REMOVE)
108  public void testIterator_knownOrderRemoveUnsupported() {
109    runIteratorTest(UNMODIFIABLE, IteratorTester.KnownOrder.KNOWN_ORDER, getOrderedElements());
110  }
111
112  @CollectionFeature.Require(absent = KNOWN_ORDER, value = SUPPORTS_ITERATOR_REMOVE)
113  public void testIterator_unknownOrderRemoveSupported() {
114    runIteratorTest(MODIFIABLE, IteratorTester.KnownOrder.UNKNOWN_ORDER, getSampleElements());
115  }
116
117  @CollectionFeature.Require(absent = {KNOWN_ORDER, SUPPORTS_ITERATOR_REMOVE})
118  public void testIterator_unknownOrderRemoveUnsupported() {
119    runIteratorTest(UNMODIFIABLE, IteratorTester.KnownOrder.UNKNOWN_ORDER, getSampleElements());
120  }
121
122  private void runIteratorTest(
123      Set<IteratorFeature> features, IteratorTester.KnownOrder knownOrder, Iterable<E> elements) {
124    new IteratorTester<E>(
125        Platform.collectionIteratorTesterNumIterations(), features, elements, knownOrder) {
126      @Override
127      protected Iterator<E> newTargetIterator() {
128        resetCollection();
129        return collection.iterator();
130      }
131
132      @Override
133      protected void verify(List<E> elements) {
134        expectContents(elements);
135      }
136    }.test();
137  }
138
139  public void testIteratorNoSuchElementException() {
140    Iterator<E> iterator = collection.iterator();
141    while (iterator.hasNext()) {
142      iterator.next();
143    }
144
145    try {
146      iterator.next();
147      fail("iterator.next() should throw NoSuchElementException");
148    } catch (NoSuchElementException expected) {
149    }
150  }
151}