/*
* Copyright (C) 2008 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.common.collect.testing;
import com.google.common.annotations.GwtCompatible;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
/**
* Base class for testers of classes (including {@link Collection}
* and {@link java.util.Map Map}) that contain elements.
*
* @param <C> the type of the container
* @param <E> the type of the container's contents
*
* @author George van den Driessche
*/
@GwtCompatible
public abstract class AbstractContainerTester<C, E>
extends AbstractTester<OneSizeTestContainerGenerator<C, E>> {
protected SampleElements<E> samples;
protected C container;
@Override public void setUp() throws Exception {
super.setUp();
samples = this.getSubjectGenerator().samples();
resetContainer();
}
/**
* @return the contents of the container under test, for use by
* {@link #expectContents(Object[]) expectContents(E...)} and its friends.
*/
protected abstract Collection<E> actualContents();
/**
* Replaces the existing container under test with a new container created
* by the subject generator.
*
* @see #resetContainer(Object) resetContainer(C)
*
* @return the new container instance.
*/
protected C resetContainer() {
return resetContainer(getSubjectGenerator().createTestSubject());
}
/**
* Replaces the existing container under test with a new container.
* This is useful when a single test method needs to create multiple
* containers while retaining the ability to use
* {@link #expectContents(Object[]) expectContents(E...)} and other
* convenience methods. The creation of multiple containers in a single
* method is discouraged in most cases, but it is vital to the iterator tests.
*
* @return the new container instance
* @param newValue the new container instance
*/
protected C resetContainer(C newValue) {
container = newValue;
return container;
}
/**
* @see #expectContents(java.util.Collection)
*
* @param elements expected contents of {@link #container}
*/
protected final void expectContents(E... elements) {
expectContents(Arrays.asList(elements));
}
/**
* Asserts that the collection under test contains exactly the given elements,
* respecting cardinality but not order. Subclasses may override this method
* to provide stronger assertions, e.g., to check ordering in lists, but
* realize that <strong>unless a test extends
* {@link com.google.common.collect.testing.testers.AbstractListTester
* AbstractListTester}, a call to {@code expectContents()} invokes this
* version</strong>.
*
* @param expected expected value of {@link #container}
*/
/*
* TODO: improve this and other implementations and move out of this framework
* for wider use
*
* TODO: could we incorporate the overriding logic from AbstractListTester, by
* examining whether the features include KNOWN_ORDER?
*/
protected void expectContents(Collection<E> expected) {
Helpers.assertEqualIgnoringOrder(expected, actualContents());
}
protected void expectUnchanged() {
expectContents(getOrderedElements());
}
/**
* Asserts that the collection under test contains exactly the elements it was
* initialized with plus the given elements, according to
* {@link #expectContents(java.util.Collection)}. In other words, for the
* default {@code expectContents()} implementation, the number of occurrences
* of each given element has increased by one since the test collection was
* created, and the number of occurrences of all other elements has not
* changed.
*
* <p>Note: This means that a test like the following will fail if
* {@code collection} is a {@code Set}:
*
* <pre>
* collection.add(existingElement);
* expectAdded(existingElement);</pre>
*
* <p>In this case, {@code collection} was not modified as a result of the
* {@code add()} call, and the test will fail because the number of
* occurrences of {@code existingElement} is unchanged.
*
* @param elements expected additional contents of {@link #container}
*/
protected final void expectAdded(E... elements) {
List<E> expected = Helpers.copyToList(getSampleElements());
expected.addAll(Arrays.asList(elements));
expectContents(expected);
}
protected final void expectAdded(int index, E... elements) {
expectAdded(index, Arrays.asList(elements));
}
protected final void expectAdded(int index, Collection<E> elements) {
List<E> expected = Helpers.copyToList(getSampleElements());
expected.addAll(index, elements);
expectContents(expected);
}
/*
* TODO: if we're testing a list, we could check indexOf(). (Doing it in
* AbstractListTester isn't enough because many tests that run on lists don't
* extends AbstractListTester.) We could also iterate over all elements to
* verify absence
*/
protected void expectMissing(E... elements) {
for (E element : elements) {
assertFalse("Should not contain " + element,
actualContents().contains(element));
}
}
protected E[] createSamplesArray() {
E[] array = getSubjectGenerator().createArray(getNumElements());
getSampleElements().toArray(array);
return array;
}
protected E[] createOrderedArray() {
E[] array = getSubjectGenerator().createArray(getNumElements());
getOrderedElements().toArray(array);
return array;
}
public static class ArrayWithDuplicate<E> {
public final E[] elements;
public final E duplicate;
private ArrayWithDuplicate(E[] elements, E duplicate) {
this.elements = elements;
this.duplicate = duplicate;
}
}
/**
* @return an array of the proper size with a duplicate element.
* The size must be at least three.
*/
protected ArrayWithDuplicate<E> createArrayWithDuplicateElement() {
E[] elements = createSamplesArray();
E duplicate = elements[(elements.length / 2) - 1];
elements[(elements.length / 2) + 1] = duplicate;
return new ArrayWithDuplicate<E>(elements, duplicate);
}
// Helper methods to improve readability of derived classes
protected int getNumElements() {
return getSubjectGenerator().getCollectionSize().getNumElements();
}
protected Collection<E> getSampleElements(int howMany) {
return getSubjectGenerator().getSampleElements(howMany);
}
protected Collection<E> getSampleElements() {
return getSampleElements(getNumElements());
}
/**
* Returns the {@linkplain #getSampleElements() sample elements} as ordered by
* {@link TestContainerGenerator#order(List)}. Tests should used this method
* only if they declare requirement {@link
* com.google.common.collect.testing.features.CollectionFeature#KNOWN_ORDER}.
*/
protected List<E> getOrderedElements() {
List<E> list = new ArrayList<E>();
for (E e : getSubjectGenerator().order(
new ArrayList<E>(getSampleElements()))) {
list.add(e);
}
return Collections.unmodifiableList(list);
}
/**
* @return a suitable location for a null element, to use when initializing
* containers for tests that involve a null element being present.
*/
protected int getNullLocation() {
return getNumElements() / 2;
}
@SuppressWarnings("unchecked")
protected MinimalCollection<E> createDisjointCollection() {
return MinimalCollection.of(samples.e3, samples.e4);
}
@SuppressWarnings("unchecked")
protected MinimalCollection<E> emptyCollection() {
return MinimalCollection.<E>of();
}
}