CollectionAbstractTest.java
/*
* Copyright (c) 2008, Harald Kuhr
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copyright 2001-2004 The Apache Software Foundation
*
* 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.twelvemonkeys.util;
import java.lang.reflect.Array;
import java.util.*;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.*;
/**
* Abstract test class for {@link java.util.Collection} methods and contracts.
* <p>
* You should create a concrete subclass of this class to test any custom
* {@link Collection} implementation. At minimum, you'll have to
* implement the {@link #makeCollection()} method. You might want to
* override some of the additional public methods as well:
* <p>
* <b>Element Population Methods</b>
* <p>
* Override these if your collection restricts what kind of elements are
* allowed (for instance, if {@code null} is not permitted):
* <ul>
* <li>{@link #getFullElements()}
* <li>{@link #getOtherElements()}
* </ul>
* <p>
* <b>Supported Operation Methods</b>
* <p>
* Override these if your collection doesn't support certain operations:
* <ul>
* <li>{@link #isAddSupported()}
* <li>{@link #isRemoveSupported()}
* <li>{@link #areEqualElementsDistinguishable()}
* <li>{@link #isNullSupported()}
* <li>{@link #isFailFastSupported()}
* </ul>
* <p>
* <b>Fixture Methods</b>
* <p>
* Fixtures are used to verify that the the operation results in correct state
* for the collection. Basically, the operation is performed against your
* collection implementation, and an identical operation is performed against a
* <i>confirmed</i> collection implementation. A confirmed collection
* implementation is something like {@code java.util.ArrayList}, which is
* known to conform exactly to its collection interface's contract. After the
* operation takes place on both your collection implementation and the
* confirmed collection implementation, the two collections are compared to see
* if their state is identical. The comparison is usually much more involved
* than a simple {@code equals} test. This verification is used to ensure
* proper modifications are made along with ensuring that the collection does
* not change when read-only modifications are made.
* <p>
* The {@link #collection} field holds an instance of your collection
* implementation; the {@link #confirmed} field holds an instance of the
* confirmed collection implementation. The {@link #resetEmpty()} and
* {@link #resetFull()} methods set these fields to empty or full collections,
* so that tests can proceed from a known state.
* <p>
* After a modification operation to both {@link #collection} and
* {@link #confirmed}, the {@link #verifyAll()} method is invoked to compare
* the results. You may want to override {@link # verifyAll ()} to perform
* additional verifications. For instance, when testing the collection
* views of a map, {@link AbstractTestMap} would override {@link # verifyAll ()} to make
* sure the map is changed after the collection view is changed.
* <p>
* If you're extending this class directly, you will have to provide
* implementations for the following:
* <ul>
* <li>{@link #makeConfirmedCollection()}
* <li>{@link #makeConfirmedFullCollection()}
* </ul>
* <p>
* Those methods should provide a confirmed collection implementation
* that's compatible with your collection implementation.
* <p>
* If you're extending {@link AbstractTestList}, {@link SetAbstractTest},
* or {@link AbstractTestBag}, you probably don't have to worry about the
* above methods, because those three classes already override the methods
* to provide standard JDK confirmed collections.<P>
* <p>
* <b>Other notes</b>
* <p>
* If your {@link Collection} fails one of these tests by design,
* you may still use this base set of cases. Simply override the
* test case (method) your {@link Collection} fails.
*
* @version $Revision: #2 $ $Date: 2008/07/15 $
*
* @author Rodney Waldhoff
* @author Paul Jack
* @author Michael A. Smith
* @author Neil O'Toole
* @author Stephen Colebourne
*/
public abstract class CollectionAbstractTest extends ObjectAbstractTest {
//
// NOTE:
//
// Collection doesn't define any semantics for equals, and recommends you
// use reference-based default behavior of Object.equals. (And a test for
// that already exists in ObjectAbstractTestCase). Tests for equality of lists, sets
// and bags will have to be written in test subclasses. Thus, there is no
// tests on Collection.equals nor any for Collection.hashCode.
//
// These fields are used by reset() and verifyAll(), and any test
// method that tests a modification.
/**
* A collection instance that will be used for testing.
*/
public Collection collection;
/**
* Confirmed collection. This is an instance of a collection that is
* confirmed to conform exactly to the java.util.Collection contract.
* Modification operations are tested by performing a mod on your
* collection, performing the exact same mod on an equivalent confirmed
* collection, and then calling verifyAll() to make sure your collection
* still matches the confirmed collection.
*/
public Collection confirmed;
//-----------------------------------------------------------------------
/**
* Specifies whether equal elements in the collection are, in fact,
* distinguishable with information not readily available. That is, if a
* particular value is to be removed from the collection, then there is
* one and only one value that can be removed, even if there are other
* elements which are equal to it.
*
* <P>In most collection cases, elements are not distinguishable (equal is
* equal), thus this method defaults to return false. In some cases,
* however, they are. For example, the collection returned from the map's
* values() collection view are backed by the map, so while there may be
* two values that are equal, their associated keys are not. Since the
* keys are distinguishable, the values are.
*
* <P>This flag is used to skip some verifications for iterator.remove()
* where it is impossible to perform an equivalent modification on the
* confirmed collection because it is not possible to determine which
* value in the confirmed collection to actually remove. Tests that
* override the default (i.e. where equal elements are distinguishable),
* should provide additional tests on iterator.remove() to make sure the
* proper elements are removed when remove() is called on the iterator.
**/
public boolean areEqualElementsDistinguishable() {
return false;
}
/**
* Returns true if the collections produced by
* {@link #makeCollection()} and {@link #makeFullCollection()}
* support the {@code add} and {@code addAll}
* operations.<P>
* Default implementation returns true. Override if your collection
* class does not support add or addAll.
*/
public boolean isAddSupported() {
return true;
}
/**
* Returns true if the collections produced by
* {@link #makeCollection()} and {@link #makeFullCollection()}
* support the {@code remove}, {@code removeAll},
* {@code retainAll}, {@code clear} and
* {@code iterator().remove()} methods.
* Default implementation returns true. Override if your collection
* class does not support removal operations.
*/
public boolean isRemoveSupported() {
return true;
}
/**
* Returns true to indicate that the collection supports holding null.
* The default implementation returns true;
*/
public boolean isNullSupported() {
return true;
}
/**
* Returns true to indicate that the collection supports fail fast iterators.
* The default implementation returns true;
*/
public boolean isFailFastSupported() {
return false;
}
/**
* Returns true to indicate that the collection supports equals() comparisons.
* This implementation returns false;
*/
public boolean isEqualsCheckable() {
return false;
}
//-----------------------------------------------------------------------
/**
* Verifies that {@link #collection} and {@link #confirmed} have
* identical state.
*/
public void verifyAll() {
int confirmedSize = confirmed.size();
assertEquals(confirmedSize, collection.size(), "Collection size should match confirmed collection's");
assertEquals(confirmed.isEmpty(), collection.isEmpty(), "Collection isEmpty() result should match confirmed collection's");
// verify the collections are the same by attempting to match each
// object in the collection and confirmed collection. To account for
// duplicates and differing orders, each confirmed element is copied
// into an array and a flag is maintained for each element to determine
// whether it has been matched once and only once. If all elements in
// the confirmed collection are matched once and only once and there
// aren't any elements left to be matched in the collection,
// verification is a success.
// copy each collection value into an array
Object[] confirmedValues = new Object[confirmedSize];
Iterator iter;
iter = confirmed.iterator();
int pos = 0;
while(iter.hasNext()) {
confirmedValues[pos++] = iter.next();
}
// allocate an array of boolean flags for tracking values that have
// been matched once and only once.
boolean[] matched = new boolean[confirmedSize];
// now iterate through the values of the collection and try to match
// the value with one in the confirmed array.
iter = collection.iterator();
while(iter.hasNext()) {
Object o = iter.next();
boolean match = false;
for(int i = 0; i < confirmedSize; i++) {
if(matched[i]) {
// skip values already matched
continue;
}
if(o == confirmedValues[i] ||
(o != null && o.equals(confirmedValues[i]))) {
// values matched
matched[i] = true;
match = true;
break;
}
}
// no match found!
if(!match) {
fail("Collection should not contain a value that the " +
"confirmed collection does not have: " + o +
"\nTest: " + collection + "\nReal: " + confirmed);
}
}
// make sure there aren't any unmatched values
for(int i = 0; i < confirmedSize; i++) {
if(!matched[i]) {
// the collection didn't match all the confirmed values
fail("Collection should contain all values that are in the confirmed collection" +
"\nTest: " + collection + "\nReal: " + confirmed);
}
}
}
//-----------------------------------------------------------------------
/**
* Resets the {@link #collection} and {@link #confirmed} fields to empty
* collections. Invoke this method before performing a modification
* test.
*/
public void resetEmpty() {
this.collection = makeCollection();
this.confirmed = makeConfirmedCollection();
}
/**
* Resets the {@link #collection} and {@link #confirmed} fields to full
* collections. Invoke this method before performing a modification
* test.
*/
public void resetFull() {
this.collection = makeFullCollection();
this.confirmed = makeConfirmedFullCollection();
}
//-----------------------------------------------------------------------
/**
* Returns a confirmed empty collection.
* For instance, an {@link java.util.ArrayList} for lists or a
* {@link java.util.HashSet} for sets.
*
* @return a confirmed empty collection
*/
public abstract Collection makeConfirmedCollection();
/**
* Returns a confirmed full collection.
* For instance, an {@link java.util.ArrayList} for lists or a
* {@link java.util.HashSet} for sets. The returned collection
* should contain the elements returned by {@link #getFullElements()}.
*
* @return a confirmed full collection
*/
public abstract Collection makeConfirmedFullCollection();
/**
* Return a new, empty {@link Collection} to be used for testing.
*/
public abstract Collection makeCollection();
/**
* Returns a full collection to be used for testing. The collection
* returned by this method should contain every element returned by
* {@link #getFullElements()}. The default implementation, in fact,
* simply invokes {@code addAll} on an empty collection with
* the results of {@link #getFullElements()}. Override this default
* if your collection doesn't support addAll.
*/
public Collection makeFullCollection() {
Collection c = makeCollection();
c.addAll(Arrays.asList(getFullElements()));
return c;
}
/**
* Returns an empty collection for Object tests.
*/
public Object makeObject() {
return makeCollection();
}
/**
* Creates a new Map Entry that is independent of the first and the map.
*/
public Map.Entry cloneMapEntry(Map.Entry entry) {
HashMap map = new HashMap();
map.put(entry.getKey(), entry.getValue());
return (Map.Entry) map.entrySet().iterator().next();
}
//-----------------------------------------------------------------------
/**
* Returns an array of objects that are contained in a collection
* produced by {@link #makeFullCollection()}. Every element in the
* returned array <I>must</I> be an element in a full collection.<P>
* The default implementation returns a heterogenous array of
* objects with some duplicates. null is added if allowed.
* Override if you require specific testing elements. Note that if you
* override {@link #makeFullCollection()}, you <I>must</I> override
* this method to reflect the contents of a full collection.
*/
public Object[] getFullElements() {
if (isNullSupported()) {
ArrayList list = new ArrayList();
list.addAll(Arrays.asList(getFullNonNullElements()));
list.add(4, null);
return list.toArray();
} else {
return (Object[]) getFullNonNullElements().clone();
}
}
/**
* Returns an array of elements that are <I>not</I> contained in a
* full collection. Every element in the returned array must
* not exist in a collection returned by {@link #makeFullCollection()}.
* The default implementation returns a heterogenous array of elements
* without null. Note that some of the tests add these elements
* to an empty or full collection, so if your collection restricts
* certain kinds of elements, you should override this method.
*/
public Object[] getOtherElements() {
return getOtherNonNullElements();
}
//-----------------------------------------------------------------------
/**
* Returns a list of elements suitable for return by
* {@link #getFullElements()}. The array returned by this method
* does not include null, but does include a variety of objects
* of different types. Override getFullElements to return
* the results of this method if your collection does not support
* the null element.
*/
public Object[] getFullNonNullElements() {
return new Object[] {
new String(""),
new String("One"),
new Integer(2),
"Three",
new Integer(4),
"One",
new Double(5),
new Float(6),
"Seven",
"Eight",
new String("Nine"),
new Integer(10),
new Short((short)11),
new Long(12),
"Thirteen",
"14",
"15",
new Byte((byte)16)
};
}
/**
* Returns the default list of objects returned by
* {@link #getOtherElements()}. Includes many objects
* of different types.
*/
public Object[] getOtherNonNullElements() {
return new Object[] {
new Integer(0),
new Float(0),
new Double(0),
"Zero",
new Short((short)0),
new Byte((byte)0),
new Long(0),
new Character('\u0000'),
"0"
};
}
/**
* Returns a list of string elements suitable for return by
* {@link #getFullElements()}. Override getFullElements to return
* the results of this method if your collection does not support
* heterogenous elements or the null element.
*/
public Object[] getFullNonNullStringElements() {
return new Object[] {
"If","the","dull","substance","of","my","flesh","were","thought",
"Injurious","distance","could","not","stop","my","way",
};
}
/**
* Returns a list of string elements suitable for return by
* {@link #getOtherElements()}. Override getOtherElements to return
* the results of this method if your collection does not support
* heterogenous elements or the null element.
*/
public Object[] getOtherNonNullStringElements() {
return new Object[] {
"For","then","despite",/* of */"space","I","would","be","brought",
"From","limits","far","remote","where","thou","dost","stay"
};
}
// Tests
//-----------------------------------------------------------------------
/**
* Tests {@link Collection#add(Object)}.
*/
@Test
public void testCollectionAdd() {
if (!isAddSupported()) return;
Object[] elements = getFullElements();
for (int i = 0; i < elements.length; i++) {
resetEmpty();
boolean r = collection.add(elements[i]);
confirmed.add(elements[i]);
verifyAll();
assertTrue(r, "Empty collection changed after add");
assertEquals(1, collection.size(), "Collection size is 1 after first add");
}
resetEmpty();
int size = 0;
for (int i = 0; i < elements.length; i++) {
boolean r = collection.add(elements[i]);
confirmed.add(elements[i]);
verifyAll();
if (r) size++;
assertEquals(size, collection.size(), "Collection size should grow after add");
assertTrue(collection.contains(elements[i]), "Collection should contain added element");
}
}
/**
* Tests {@link Collection#addAll(Collection)}.
*/
@Test
public void testCollectionAddAll() {
if (!isAddSupported()) return;
resetEmpty();
Object[] elements = getFullElements();
boolean r = collection.addAll(Arrays.asList(elements));
confirmed.addAll(Arrays.asList(elements));
verifyAll();
assertTrue(r, "Empty collection should change after addAll");
for (int i = 0; i < elements.length; i++) {
assertTrue(collection.contains(elements[i]), "Collection should contain added element");
}
resetFull();
int size = collection.size();
elements = getOtherElements();
r = collection.addAll(Arrays.asList(elements));
confirmed.addAll(Arrays.asList(elements));
verifyAll();
assertTrue(r, "Full collection should change after addAll");
for (int i = 0; i < elements.length; i++) {
assertTrue(collection.contains(elements[i]), "Full collection should contain added element");
}
assertEquals(size + elements.length, collection.size(), "Size should increase after addAll");
resetFull();
size = collection.size();
r = collection.addAll(Arrays.asList(getFullElements()));
confirmed.addAll(Arrays.asList(getFullElements()));
verifyAll();
if (r) {
assertTrue(size < collection.size(), "Size should increase if addAll returns true");
} else {
assertEquals(size, collection.size(), "Size should not change if addAll returns false");
}
}
/**
* If {@link #isAddSupported()} returns false, tests that add operations
* raise <code>UnsupportedOperationException.
*/
@Test
public void testUnsupportedAdd() {
if (isAddSupported()) return;
resetEmpty();
try {
collection.add(new Object());
fail("Emtpy collection should not support add.");
} catch (UnsupportedOperationException e) {
// expected
}
// make sure things didn't change even if the expected exception was
// thrown.
verifyAll();
try {
collection.addAll(Arrays.asList(getFullElements()));
fail("Emtpy collection should not support addAll.");
} catch (UnsupportedOperationException e) {
// expected
}
// make sure things didn't change even if the expected exception was
// thrown.
verifyAll();
resetFull();
try {
collection.add(new Object());
fail("Full collection should not support add.");
} catch (UnsupportedOperationException e) {
// expected
}
// make sure things didn't change even if the expected exception was
// thrown.
verifyAll();
try {
collection.addAll(Arrays.asList(getOtherElements()));
fail("Full collection should not support addAll.");
} catch (UnsupportedOperationException e) {
// expected
}
// make sure things didn't change even if the expected exception was
// thrown.
verifyAll();
}
/**
* Test {@link Collection#clear()}.
*/
@Test
public void testCollectionClear() {
if (!isRemoveSupported()) return;
resetEmpty();
collection.clear(); // just to make sure it doesn't raise anything
verifyAll();
resetFull();
collection.clear();
confirmed.clear();
verifyAll();
}
/**
* Tests {@link Collection#contains(Object)}.
*/
public void testCollectionContains() {
Object[] elements;
resetEmpty();
elements = getFullElements();
for(int i = 0; i < elements.length; i++) {
assertTrue(!collection.contains(elements[i]), "Empty collection shouldn't contain element[" + i + "]");
}
// make sure calls to "contains" don't change anything
verifyAll();
elements = getOtherElements();
for(int i = 0; i < elements.length; i++) {
assertTrue(!collection.contains(elements[i]), "Empty collection shouldn't contain element[" + i + "]");
}
// make sure calls to "contains" don't change anything
verifyAll();
resetFull();
elements = getFullElements();
for(int i = 0; i < elements.length; i++) {
assertTrue(collection.contains(elements[i]), "Full collection should contain element[" + i + "]");
}
// make sure calls to "contains" don't change anything
verifyAll();
resetFull();
elements = getOtherElements();
for(int i = 0; i < elements.length; i++) {
assertTrue(!collection.contains(elements[i]), "Full collection shouldn't contain element");
}
}
/**
* Tests {@link Collection#containsAll(Collection)}.
*/
@Test
public void testCollectionContainsAll() {
resetEmpty();
Collection col = new HashSet();
assertTrue(collection.containsAll(col),
"Every Collection should contain all elements of an " +
"empty Collection.");
col.addAll(Arrays.asList(getOtherElements()));
assertTrue(!collection.containsAll(col),
"Empty Collection shouldn't contain all elements of " +
"a non-empty Collection.");
// make sure calls to "containsAll" don't change anything
verifyAll();
resetFull();
assertTrue(!collection.containsAll(col), "Full collection shouldn't contain other elements");
col.clear();
col.addAll(Arrays.asList(getFullElements()));
assertTrue(collection.containsAll(col), "Full collection should containAll full elements");
// make sure calls to "containsAll" don't change anything
verifyAll();
int min = (getFullElements().length < 2 ? 0 : 2);
int max = (getFullElements().length == 1 ? 1 :
(getFullElements().length <= 5 ? getFullElements().length - 1 : 5));
col = Arrays.asList(getFullElements()).subList(min, max);
assertTrue(collection.containsAll(col), "Full collection should containAll partial full " +
"elements");
assertTrue(collection.containsAll(collection), "Full collection should containAll itself");
// make sure calls to "containsAll" don't change anything
verifyAll();
col = new ArrayList();
col.addAll(Arrays.asList(getFullElements()));
col.addAll(Arrays.asList(getFullElements()));
assertTrue(collection.containsAll(col), "Full collection should containAll duplicate full " +
"elements");
// make sure calls to "containsAll" don't change anything
verifyAll();
}
/**
* Tests {@link Collection#isEmpty()}.
*/
@Test
public void testCollectionIsEmpty() {
resetEmpty();
assertEquals(true, collection.isEmpty(), "New Collection should be empty.");
// make sure calls to "isEmpty() don't change anything
verifyAll();
resetFull();
assertEquals(false, collection.isEmpty(), "Full collection shouldn't be empty");
// make sure calls to "isEmpty() don't change anything
verifyAll();
}
/**
* Tests the read-only functionality of {@link Collection#iterator()}.
*/
@Test
public void testCollectionIterator() {
resetEmpty();
Iterator it1 = collection.iterator();
assertEquals(false, it1.hasNext(), "Iterator for empty Collection shouldn't have next.");
try {
it1.next();
fail("Iterator at end of Collection should throw " +
"NoSuchElementException when next is called.");
} catch(NoSuchElementException e) {
// expected
}
// make sure nothing has changed after non-modification
verifyAll();
resetFull();
it1 = collection.iterator();
for (int i = 0; i < collection.size(); i++) {
assertTrue(it1.hasNext(), "Iterator for full collection should haveNext");
it1.next();
}
assertTrue(!it1.hasNext(), "Iterator should be finished");
ArrayList list = new ArrayList();
it1 = collection.iterator();
for (int i = 0; i < collection.size(); i++) {
Object next = it1.next();
assertTrue(collection.contains(next), "Collection should contain element returned by " +
"its iterator");
list.add(next);
}
try {
it1.next();
fail("iterator.next() should raise NoSuchElementException " +
"after it finishes");
} catch (NoSuchElementException e) {
// expected
}
// make sure nothing has changed after non-modification
verifyAll();
}
/**
* Tests removals from {@link Collection#iterator()}.
*/
@Test
public void testCollectionIteratorRemove() {
if (!isRemoveSupported()) return;
resetEmpty();
try {
collection.iterator().remove();
fail("New iterator.remove should raise IllegalState");
} catch (IllegalStateException e) {
// expected
}
verifyAll();
try {
Iterator iter = collection.iterator();
iter.hasNext();
iter.remove();
fail("New iterator.remove should raise IllegalState " +
"even after hasNext");
} catch (IllegalStateException e) {
// expected
}
verifyAll();
resetFull();
int size = collection.size();
Iterator iter = collection.iterator();
while (iter.hasNext()) {
Object o = iter.next();
// TreeMap reuses the Map Entry, so the verify below fails
// Clone it here if necessary
if (o instanceof Map.Entry) {
o = cloneMapEntry((Map.Entry) o);
}
iter.remove();
// if the elements aren't distinguishable, we can just remove a
// matching element from the confirmed collection and verify
// contents are still the same. Otherwise, we don't have the
// ability to distinguish the elements and determine which to
// remove from the confirmed collection (in which case, we don't
// verify because we don't know how).
//
// see areEqualElementsDistinguishable()
if(!areEqualElementsDistinguishable()) {
confirmed.remove(o);
verifyAll();
}
size--;
assertEquals(size, collection.size(), "Collection should shrink by one after " +
"iterator.remove");
}
assertTrue(collection.isEmpty(), "Collection should be empty after iterator purge");
resetFull();
iter = collection.iterator();
iter.next();
iter.remove();
try {
iter.remove();
fail("Second iter.remove should raise IllegalState");
} catch (IllegalStateException e) {
// expected
}
}
/**
* Tests {@link Collection#remove(Object)}.
*/
@Test
public void testCollectionRemove() {
if (!isRemoveSupported()) return;
resetEmpty();
Object[] elements = getFullElements();
for (int i = 0; i < elements.length; i++) {
assertTrue(!collection.remove(elements[i]), "Shouldn't remove nonexistent element");
verifyAll();
}
Object[] other = getOtherElements();
resetFull();
for (int i = 0; i < other.length; i++) {
assertTrue(!collection.remove(other[i]), "Shouldn't remove nonexistent other element");
verifyAll();
}
int size = collection.size();
for (int i = 0; i < elements.length; i++) {
resetFull();
assertTrue(collection.remove(elements[i]), "Collection should remove extant element: " + elements[i]);
// if the elements aren't distinguishable, we can just remove a
// matching element from the confirmed collection and verify
// contents are still the same. Otherwise, we don't have the
// ability to distinguish the elements and determine which to
// remove from the confirmed collection (in which case, we don't
// verify because we don't know how).
//
// see areEqualElementsDistinguishable()
if(!areEqualElementsDistinguishable()) {
confirmed.remove(elements[i]);
verifyAll();
}
assertEquals(size - 1, collection.size(), "Collection should shrink after remove");
}
}
/**
* Tests {@link Collection#removeAll(Collection)}.
*/
@Test
public void testCollectionRemoveAll() {
if (!isRemoveSupported()) return;
resetEmpty();
assertTrue(!collection.removeAll(Collections.EMPTY_SET),
"Emtpy collection removeAll should return false for " +
"empty input");
verifyAll();
assertTrue(!collection.removeAll(new ArrayList(collection)),
"Emtpy collection removeAll should return false for " +
"nonempty input");
verifyAll();
resetFull();
assertTrue(!collection.removeAll(Collections.EMPTY_SET),
"Full collection removeAll should return false for " +
"empty input");
verifyAll();
assertTrue(!collection.removeAll(Arrays.asList(getOtherElements())),
"Full collection removeAll should return false for other elements");
verifyAll();
assertTrue(collection.removeAll(new HashSet(collection)),
"Full collection removeAll should return true for full elements");
confirmed.removeAll(new HashSet(confirmed));
verifyAll();
resetFull();
int size = collection.size();
int min = (getFullElements().length < 2 ? 0 : 2);
int max = (getFullElements().length == 1 ? 1 :
(getFullElements().length <= 5 ? getFullElements().length - 1 : 5));
Collection all = Arrays.asList(getFullElements()).subList(min, max);
assertTrue(collection.removeAll(all), "Full collection removeAll should work");
confirmed.removeAll(all);
verifyAll();
assertTrue(collection.size() < size, "Collection should shrink after removeAll");
Iterator iter = all.iterator();
while (iter.hasNext()) {
assertTrue(!collection.contains(iter.next()), "Collection shouldn't contain removed element");
}
}
/**
* Tests {@link Collection#retainAll(Collection)}.
*/
@Test
public void testCollectionRetainAll() {
if (!isRemoveSupported()) return;
resetEmpty();
List elements = Arrays.asList(getFullElements());
List other = Arrays.asList(getOtherElements());
assertTrue(!collection.retainAll(Collections.EMPTY_SET), "Empty retainAll() should return false");
verifyAll();
assertTrue(!collection.retainAll(elements), "Empty retainAll() should return false");
verifyAll();
resetFull();
assertTrue(collection.retainAll(Collections.EMPTY_SET), "Collection should change from retainAll empty");
confirmed.retainAll(Collections.EMPTY_SET);
verifyAll();
resetFull();
assertTrue(collection.retainAll(other), "Collection changed from retainAll other");
confirmed.retainAll(other);
verifyAll();
resetFull();
int size = collection.size();
assertTrue(!collection.retainAll(elements), "Collection shouldn't change from retainAll elements");
verifyAll();
assertEquals(size, collection.size(), "Collection size shouldn't change");
if (getFullElements().length > 1) {
resetFull();
size = collection.size();
int min = (getFullElements().length < 2 ? 0 : 2);
int max = (getFullElements().length <= 5 ? getFullElements().length - 1 : 5);
assertTrue(collection.retainAll(elements.subList(min, max)), "Collection should changed by partial retainAll");
confirmed.retainAll(elements.subList(min, max));
verifyAll();
Iterator iter = collection.iterator();
while (iter.hasNext()) {
assertTrue(elements.subList(min, max).contains(iter.next()), "Collection only contains retained element");
}
}
resetFull();
HashSet set = new HashSet(elements);
size = collection.size();
assertTrue(!collection.retainAll(set),
"Collection shouldn't change from retainAll without duplicate elements");
verifyAll();
assertEquals( size, collection.size(),
"Collection size didn't change from nonduplicate retainAll");
}
/**
* Tests {@link Collection#size()}.
*/
@Test
public void testCollectionSize() {
resetEmpty();
assertEquals(0, collection.size(), "Size of new Collection is 0.");
resetFull();
assertTrue(collection.size() > 0, "Size of full collection should be greater than zero");
}
/**
* Tests {@link Collection#toArray()}.
*/
public void testCollectionToArray() {
resetEmpty();
assertEquals(0, collection.toArray().length, "Empty Collection should return empty array for toArray");
resetFull();
Object[] array = collection.toArray();
assertEquals(array.length, collection.size(), "Full collection toArray should be same size as collection");
Object[] confirmedArray = confirmed.toArray();
assertEquals(confirmedArray.length, array.length,
"length of array from confirmed collection should match the length of the collection's array");
boolean[] matched = new boolean[array.length];
for (int i = 0; i < array.length; i++) {
assertTrue(collection.contains(array[i]), "Collection should contain element in toArray");
boolean match = false;
// find a match in the confirmed array
for(int j = 0; j < array.length; j++) {
// skip already matched
if(matched[j]) continue;
if(array[i] == confirmedArray[j] ||
(array[i] != null && array[i].equals(confirmedArray[j]))) {
matched[j] = true;
match = true;
break;
}
}
if(!match) {
fail("element " + i + " in returned array should be found " +
"in the confirmed collection's array");
}
}
for(int i = 0; i < matched.length; i++) {
assertEquals(true, matched[i], "Collection should return all its elements in toArray");
}
}
/**
* Tests {@link Collection#toArray(Object[])}.
*/
@SuppressWarnings({"SuspiciousToArrayCall", "RedundantCast"})
@Test
public void testCollectionToArray2() {
resetEmpty();
Object[] a = new Object[] { new Object(), null, null };
Object[] array = collection.toArray(a);
assertArrayEquals(array, a, "Given array shouldn't shrink");
assertNull(a[0], "Last element should be set to null");
verifyAll();
resetFull();
try {
collection.toArray(new Void[0]);
fail("toArray(new Void[0]) should raise ArrayStore");
} catch (ArrayStoreException e) {
// expected
}
verifyAll();
try {
collection.toArray((Object[]) null);
fail("toArray(null) should raise NPE");
} catch (NullPointerException e) {
// expected
}
verifyAll();
array = collection.toArray(new Object[0]);
a = collection.toArray();
assertEquals(Arrays.asList(array), Arrays.asList(a), "toArrays should be equal");
// Figure out if they're all the same class
// TODO: It'd be nicer to detect a common superclass
HashSet<Class<?>> classes = new HashSet<>();
for (int i = 0; i < array.length; i++) {
classes.add((array[i] == null) ? null : array[i].getClass());
}
if (classes.size() > 1) return;
Class<?> cl = (Class<?>)classes.iterator().next();
if (Map.Entry.class.isAssignableFrom(cl)) { // check needed for protective cases like Predicated/Unmod map entrySet
cl = Map.Entry.class;
}
a = (Object[])Array.newInstance(cl, 0);
array = collection.toArray(a);
assertEquals(a.getClass(), array.getClass(), "toArray(Object[]) should return correct array type");
assertEquals(Arrays.asList(array),
Arrays.asList(collection.toArray()),
"type-specific toArrays should be equal");
verifyAll();
}
/**
* Tests {@code toString} on a collection.
*/
@Test
public void testCollectionToString() {
resetEmpty();
assertTrue(collection.toString() != null, "toString shouldn't return null");
resetFull();
assertTrue(collection.toString() != null, "toString shouldn't return null");
}
/**
* If isRemoveSupported() returns false, tests to see that remove
* operations raise an UnsupportedOperationException.
*/
@Test
public void testUnsupportedRemove() {
if (isRemoveSupported()) return;
resetEmpty();
try {
collection.clear();
fail("clear should raise UnsupportedOperationException");
} catch (UnsupportedOperationException e) {
// expected
}
verifyAll();
try {
collection.remove(null);
fail("remove should raise UnsupportedOperationException");
} catch (UnsupportedOperationException e) {
// expected
}
verifyAll();
try {
collection.removeAll(null);
fail("removeAll should raise UnsupportedOperationException");
} catch (UnsupportedOperationException e) {
// expected
}
verifyAll();
try {
collection.retainAll(null);
fail("removeAll should raise UnsupportedOperationException");
} catch (UnsupportedOperationException e) {
// expected
}
verifyAll();
resetFull();
try {
Iterator iterator = collection.iterator();
iterator.next();
iterator.remove();
fail("iterator.remove should raise UnsupportedOperationException");
} catch (UnsupportedOperationException e) {
// expected
}
verifyAll();
}
/**
* Tests that the collection's iterator is fail-fast.
*/
@Test
public void testCollectionIteratorFailFast() {
if (!isFailFastSupported()) return;
if (isAddSupported()) {
resetFull();
try {
Iterator iter = collection.iterator();
Object o = getOtherElements()[0];
collection.add(o);
confirmed.add(o);
iter.next();
fail("next after add should raise ConcurrentModification");
} catch (ConcurrentModificationException e) {
// expected
}
verifyAll();
resetFull();
try {
Iterator iter = collection.iterator();
collection.addAll(Arrays.asList(getOtherElements()));
confirmed.addAll(Arrays.asList(getOtherElements()));
iter.next();
fail("next after addAll should raise ConcurrentModification");
} catch (ConcurrentModificationException e) {
// expected
}
verifyAll();
}
if (!isRemoveSupported()) return;
resetFull();
try {
Iterator iter = collection.iterator();
collection.clear();
iter.next();
fail("next after clear should raise ConcurrentModification");
} catch (ConcurrentModificationException e) {
// expected
} catch (NoSuchElementException e) {
// (also legal given spec)
}
resetFull();
try {
Iterator iter = collection.iterator();
collection.remove(getFullElements()[0]);
iter.next();
fail("next after remove should raise ConcurrentModification");
} catch (ConcurrentModificationException e) {
// expected
}
resetFull();
try {
Iterator iter = collection.iterator();
List sublist = Arrays.asList(getFullElements()).subList(2,5);
collection.removeAll(sublist);
iter.next();
fail("next after removeAll should raise ConcurrentModification");
} catch (ConcurrentModificationException e) {
// expected
}
resetFull();
try {
Iterator iter = collection.iterator();
List sublist = Arrays.asList(getFullElements()).subList(2,5);
collection.retainAll(sublist);
iter.next();
fail("next after retainAll should raise ConcurrentModification");
} catch (ConcurrentModificationException e) {
// expected
}
}
/*
@Test
public void testSerializeDeserializeThenCompare() throws Exception {
Object obj = makeCollection();
if (obj instanceof Serializable && isTestSerialization()) {
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(buffer);
out.writeObject(obj);
out.close();
ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(buffer.toByteArray()));
Object dest = in.readObject();
in.close();
if (isEqualsCheckable()) {
assertEquals("obj != deserialize(serialize(obj)) - EMPTY Collection", obj, dest);
}
}
obj = makeFullCollection();
if (obj instanceof Serializable && isTestSerialization()) {
ByteArrayOutputStream buffer = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(buffer);
out.writeObject(obj);
out.close();
ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(buffer.toByteArray()));
Object dest = in.readObject();
in.close();
if (isEqualsCheckable()) {
assertEquals("obj != deserialize(serialize(obj)) - FULL Collection", obj, dest);
}
}
}
*/
}