CollectionIteratorTester.java revision 0888a09821a98ac0680fad765217302858e70fa4 
1/*
2 * Copyright (C) 2008 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.common.collect.testing.testers;
18
19import static com.google.common.collect.testing.IteratorFeature.MODIFIABLE;
20import static com.google.common.collect.testing.IteratorFeature.UNMODIFIABLE;
21import static com.google.common.collect.testing.features.CollectionFeature.KNOWN_ORDER;
22import static com.google.common.collect.testing.features.CollectionFeature.SUPPORTS_ITERATOR_REMOVE;
23
24import com.google.common.annotations.GwtCompatible;
25import com.google.common.annotations.GwtIncompatible;
26import com.google.common.collect.testing.AbstractCollectionTester;
27import com.google.common.collect.testing.Helpers;
28import com.google.common.collect.testing.IteratorFeature;
29import com.google.common.collect.testing.IteratorTester;
30import com.google.common.collect.testing.features.CollectionFeature;
31
32import java.lang.reflect.Method;
33import java.util.ArrayList;
34import java.util.Arrays;
35import java.util.Iterator;
36import java.util.List;
37import java.util.NoSuchElementException;
38import java.util.Set;
39
40/**
41 * A generic JUnit test which tests {@code iterator} operations on a collection.
42 * Can't be invoked directly; please see
43 * {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
44 *
45 * @author Chris Povirk
46 */
47@GwtCompatible(emulated = true)
48public class CollectionIteratorTester<E> extends AbstractCollectionTester<E> {
49  public void testIterator() {
50    List<E> iteratorElements = new ArrayList<E>();
51    for (E element : collection) { // uses iterator()
52      iteratorElements.add(element);
53    }
54    Helpers.assertEqualIgnoringOrder(
55        Arrays.asList(createSamplesArray()), iteratorElements);
56  }
57
58  @CollectionFeature.Require(KNOWN_ORDER)
59  public void testIterationOrdering() {
60    List<E> iteratorElements = new ArrayList<E>();
61    for (E element : collection) { // uses iterator()
62      iteratorElements.add(element);
63    }
64    List<E> expected = Helpers.copyToList(getOrderedElements());
65    assertEquals("Different ordered iteration", expected, iteratorElements);
66  }
67
68  // TODO: switch to DerivedIteratorTestSuiteBuilder
69
70  @CollectionFeature.Require({KNOWN_ORDER, SUPPORTS_ITERATOR_REMOVE})
71  public void testIterator_knownOrderRemoveSupported() {
72    runIteratorTest(MODIFIABLE, IteratorTester.KnownOrder.KNOWN_ORDER,
73        getOrderedElements());
74  }
75
76  @CollectionFeature.Require(value = KNOWN_ORDER, absent = SUPPORTS_ITERATOR_REMOVE)
77  public void testIterator_knownOrderRemoveUnsupported() {
78    runIteratorTest(UNMODIFIABLE, IteratorTester.KnownOrder.KNOWN_ORDER,
79        getOrderedElements());
80  }
81
82  @CollectionFeature.Require(absent = KNOWN_ORDER, value = SUPPORTS_ITERATOR_REMOVE)
83  public void testIterator_unknownOrderRemoveSupported() {
84    runIteratorTest(MODIFIABLE, IteratorTester.KnownOrder.UNKNOWN_ORDER,
85        getSampleElements());
86  }
87
88  @CollectionFeature.Require(absent = {KNOWN_ORDER, SUPPORTS_ITERATOR_REMOVE})
89  public void testIterator_unknownOrderRemoveUnsupported() {
90    runIteratorTest(UNMODIFIABLE, IteratorTester.KnownOrder.UNKNOWN_ORDER,
91        getSampleElements());
92  }
93
94  private void runIteratorTest(Set<IteratorFeature> features,
95      IteratorTester.KnownOrder knownOrder, Iterable<E> elements) {
96    new IteratorTester<E>(Platform.collectionIteratorTesterNumIterations(), features, elements,
97        knownOrder) {
98      @Override protected Iterator<E> newTargetIterator() {
99        resetCollection();
100        return collection.iterator();
101      }
102
103      @Override protected void verify(List<E> elements) {
104        expectContents(elements);
105      }
106    }.test();
107  }
108
109  public void testIteratorNoSuchElementException() {
110    Iterator<E> iterator = collection.iterator();
111    while (iterator.hasNext()) {
112      iterator.next();
113    }
114
115    try {
116      iterator.next();
117      fail("iterator.next() should throw NoSuchElementException");
118    } catch (NoSuchElementException expected) {}
119  }
120
121  /**
122   * Returns the {@link Method} instance for
123   * {@link #testIterator_knownOrderRemoveUnsupported()} so that tests of
124   * {@code ArrayStack} can suppress it with
125   * {@code FeatureSpecificTestSuiteBuilder.suppressing()}. {@code ArrayStack}
126   * supports {@code remove()} on only the first element, and the iterator
127   * tester can't handle that.
128   */
129  @GwtIncompatible("reflection")
130  public static Method getIteratorKnownOrderRemoveUnsupportedMethod() {
131    return Helpers.getMethod(
132        CollectionIteratorTester.class, "testIterator_knownOrderRemoveUnsupported");
133  }
134
135  /**
136   * Returns the {@link Method} instance for
137   * {@link #testIterator_knownOrderRemoveSupported()} so that tests of
138   * {@code Sets.filter} can suppress it under JDK5.
139   */
140  @GwtIncompatible("reflection")
141  public static Method getIteratorKnownOrderRemoveSupportedMethod() {
142    return Helpers.getMethod(
143        CollectionIteratorTester.class, "testIterator_knownOrderRemoveSupported");
144  }
145}
146