test/tck/Collection8Test.java

/*
 * Written by Doug Lea and Martin Buchholz with assistance from
 * members of JCP JSR-166 Expert Group and released to the public
 * domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 */

import static java.util.concurrent.TimeUnit.MILLISECONDS;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Deque;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.Queue;
import java.util.Spliterator;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executors;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Consumer;
import java.util.function.Predicate;

import junit.framework.Test;

/**
 * Contains tests applicable to all jdk8+ Collection implementations.
 * An extension of CollectionTest.
 */
public class Collection8Test extends JSR166TestCase {
    final CollectionImplementation impl;

    /** Tests are parameterized by a Collection implementation. */
    Collection8Test(CollectionImplementation impl, String methodName) {
        super(methodName);
        this.impl = impl;
    }

    public static Test testSuite(CollectionImplementation impl) {
        return parameterizedTestSuite(Collection8Test.class,
                                      CollectionImplementation.class,
                                      impl);
    }

    /** Checks properties of empty collections. */
    public void testEmptyMeansEmpty() {
        Collection c = impl.emptyCollection();
        assertTrue(c.isEmpty());
        assertEquals(0, c.size());
        assertEquals("[]", c.toString());
        {
            Object[] a = c.toArray();
            assertEquals(0, a.length);
            assertSame(Object[].class, a.getClass());
        }
        {
            Object[] a = new Object[0];
            assertSame(a, c.toArray(a));
        }
        {
            Integer[] a = new Integer[0];
            assertSame(a, c.toArray(a));
        }
        {
            Integer[] a = { 1, 2, 3};
            assertSame(a, c.toArray(a));
            assertNull(a[0]);
            assertSame(2, a[1]);
            assertSame(3, a[2]);
        }
        assertIteratorExhausted(c.iterator());
        Consumer alwaysThrows = (e) -> { throw new AssertionError(); };
        c.forEach(alwaysThrows);
        c.iterator().forEachRemaining(alwaysThrows);
        c.spliterator().forEachRemaining(alwaysThrows);
        assertFalse(c.spliterator().tryAdvance(alwaysThrows));
        if (c.spliterator().hasCharacteristics(Spliterator.SIZED))
            assertEquals(0, c.spliterator().estimateSize());
        if (Queue.class.isAssignableFrom(impl.klazz())) {
            Queue q = (Queue) c;
            assertNull(q.peek());
            assertNull(q.poll());
        }
        if (Deque.class.isAssignableFrom(impl.klazz())) {
            Deque d = (Deque) c;
            assertNull(d.peekFirst());
            assertNull(d.peekLast());
            assertNull(d.pollFirst());
            assertNull(d.pollLast());
            assertIteratorExhausted(d.descendingIterator());
            d.descendingIterator().forEachRemaining(alwaysThrows);
        }
    }

    public void testNullPointerExceptions() {
        Collection c = impl.emptyCollection();
        assertThrows(
            NullPointerException.class,
            () -> c.addAll(null),
            () -> c.containsAll(null),
            () -> c.retainAll(null),
            () -> c.removeAll(null),
            () -> c.removeIf(null),
            () -> c.forEach(null),
            () -> c.iterator().forEachRemaining(null),
            () -> c.spliterator().forEachRemaining(null),
            () -> c.spliterator().tryAdvance(null),
            () -> c.toArray(null));

        if (!impl.permitsNulls()) {
            assertThrows(
                NullPointerException.class,
                () -> c.add(null));
        }
        if (!impl.permitsNulls()
            && Queue.class.isAssignableFrom(impl.klazz())) {
            Queue q = (Queue) c;
            assertThrows(
                NullPointerException.class,
                () -> q.offer(null));
        }
        if (!impl.permitsNulls()
            && Deque.class.isAssignableFrom(impl.klazz())) {
            Deque d = (Deque) c;
            assertThrows(
                NullPointerException.class,
                () -> d.addFirst(null),
                () -> d.addLast(null),
                () -> d.offerFirst(null),
                () -> d.offerLast(null),
                () -> d.push(null),
                () -> d.descendingIterator().forEachRemaining(null));
        }
    }

    public void testNoSuchElementExceptions() {
        Collection c = impl.emptyCollection();
        assertThrows(
            NoSuchElementException.class,
            () -> c.iterator().next());

        if (Queue.class.isAssignableFrom(impl.klazz())) {
            Queue q = (Queue) c;
            assertThrows(
                NoSuchElementException.class,
                () -> q.element(),
                () -> q.remove());
        }
        if (Deque.class.isAssignableFrom(impl.klazz())) {
            Deque d = (Deque) c;
            assertThrows(
                NoSuchElementException.class,
                () -> d.getFirst(),
                () -> d.getLast(),
                () -> d.removeFirst(),
                () -> d.removeLast(),
                () -> d.pop(),
                () -> d.descendingIterator().next());
        }
    }

    public void testRemoveIf() {
        Collection c = impl.emptyCollection();
        ThreadLocalRandom rnd = ThreadLocalRandom.current();
        int n = rnd.nextInt(6);
        for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
        AtomicReference threwAt = new AtomicReference(null);
        ArrayList survivors = new ArrayList(c);
        ArrayList accepts = new ArrayList();
        ArrayList rejects = new ArrayList();
        Predicate randomPredicate = (e) -> {
            assertNull(threwAt.get());
            switch (rnd.nextInt(3)) {
            case 0: accepts.add(e); return true;
            case 1: rejects.add(e); return false;
            case 2: threwAt.set(e); throw new ArithmeticException();
            default: throw new AssertionError();
            }
        };
        try {
            assertFalse(survivors.contains(null));
            try {
                boolean modified = c.removeIf(randomPredicate);
                if (!modified) {
                    assertNull(threwAt.get());
                    assertEquals(n, rejects.size());
                    assertEquals(0, accepts.size());
                }
            } catch (ArithmeticException ok) {}
            survivors.removeAll(accepts);
            assertEquals(n - accepts.size(), c.size());
            assertTrue(c.containsAll(survivors));
            assertTrue(survivors.containsAll(rejects));
            for (Object x : accepts) assertFalse(c.contains(x));
            if (threwAt.get() == null)
                assertEquals(accepts.size() + rejects.size(), n);
        } catch (Throwable ex) {
            System.err.println(impl.klazz());
            System.err.printf("c=%s%n", c);
            System.err.printf("n=%d%n", n);
            System.err.printf("accepts=%s%n", accepts);
            System.err.printf("rejects=%s%n", rejects);
            System.err.printf("survivors=%s%n", survivors);
            System.err.printf("threw=%s%n", threwAt.get());
            throw ex;
        }
    }

    /**
     * Various ways of traversing a collection yield same elements
     */
    public void testIteratorEquivalence() {
        Collection c = impl.emptyCollection();
        ThreadLocalRandom rnd = ThreadLocalRandom.current();
        int n = rnd.nextInt(6);
        for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
        ArrayList iterated = new ArrayList();
        ArrayList iteratedForEachRemaining = new ArrayList();
        ArrayList spliterated = new ArrayList();
        ArrayList foreached = new ArrayList();
        for (Object x : c) iterated.add(x);
        c.iterator().forEachRemaining(e -> iteratedForEachRemaining.add(e));
        c.spliterator().forEachRemaining(e -> spliterated.add(e));
        c.forEach(e -> foreached.add(e));
        boolean ordered =
            c.spliterator().hasCharacteristics(Spliterator.ORDERED);
        if (c instanceof List || c instanceof Deque)
            assertTrue(ordered);
        if (ordered) {
            assertEquals(iterated, iteratedForEachRemaining);
            assertEquals(iterated, spliterated);
            assertEquals(iterated, foreached);
        } else {
            HashSet cset = new HashSet(c);
            assertEquals(cset, new HashSet(iterated));
            assertEquals(cset, new HashSet(iteratedForEachRemaining));
            assertEquals(cset, new HashSet(spliterated));
            assertEquals(cset, new HashSet(foreached));
        }
        if (c instanceof Deque) {
            Deque d = (Deque) c;
            ArrayList descending = new ArrayList();
            ArrayList descendingForEachRemaining = new ArrayList();
            for (Iterator it = d.descendingIterator(); it.hasNext(); )
                descending.add(it.next());
            d.descendingIterator().forEachRemaining(
                e -> descendingForEachRemaining.add(e));
            Collections.reverse(descending);
            Collections.reverse(descendingForEachRemaining);
            assertEquals(iterated, descending);
            assertEquals(iterated, descendingForEachRemaining);
        }
    }

    /**
     * Calling Iterator#remove() after Iterator#forEachRemaining
     * should remove last element
     */
    public void testRemoveAfterForEachRemaining() {
        Collection c = impl.emptyCollection();
        ThreadLocalRandom rnd = ThreadLocalRandom.current();
        {
            int n = 3 + rnd.nextInt(2);
            for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
            Iterator it = c.iterator();
            assertTrue(it.hasNext());
            assertEquals(impl.makeElement(0), it.next());
            assertTrue(it.hasNext());
            assertEquals(impl.makeElement(1), it.next());
            it.forEachRemaining((e) -> {});
            it.remove();
            assertEquals(n - 1, c.size());
            for (int i = 0; i < n - 1; i++)
                assertTrue(c.contains(impl.makeElement(i)));
            assertFalse(c.contains(impl.makeElement(n - 1)));
        }
        if (c instanceof Deque) {
            Deque d = (Deque) impl.emptyCollection();
            int n = 3 + rnd.nextInt(2);
            for (int i = 0; i < n; i++) d.add(impl.makeElement(i));
            Iterator it = d.descendingIterator();
            assertTrue(it.hasNext());
            assertEquals(impl.makeElement(n - 1), it.next());
            assertTrue(it.hasNext());
            assertEquals(impl.makeElement(n - 2), it.next());
            it.forEachRemaining((e) -> {});
            it.remove();
            assertEquals(n - 1, d.size());
            for (int i = 1; i < n; i++)
                assertTrue(d.contains(impl.makeElement(i)));
            assertFalse(d.contains(impl.makeElement(0)));
        }
    }

    /**
     * stream().forEach returns elements in the collection
     */
    public void testStreamForEach() throws Throwable {
        final Collection c = impl.emptyCollection();
        final AtomicLong count = new AtomicLong(0L);
        final Object x = impl.makeElement(1);
        final Object y = impl.makeElement(2);
        final ArrayList found = new ArrayList();
        Consumer<Object> spy = (o) -> { found.add(o); };
        c.stream().forEach(spy);
        assertTrue(found.isEmpty());

        assertTrue(c.add(x));
        c.stream().forEach(spy);
        assertEquals(Collections.singletonList(x), found);
        found.clear();

        assertTrue(c.add(y));
        c.stream().forEach(spy);
        assertEquals(2, found.size());
        assertTrue(found.contains(x));
        assertTrue(found.contains(y));
        found.clear();

        c.clear();
        c.stream().forEach(spy);
        assertTrue(found.isEmpty());
    }

    public void testStreamForEachConcurrentStressTest() throws Throwable {
        if (!impl.isConcurrent()) return;
        final Collection c = impl.emptyCollection();
        final long testDurationMillis = timeoutMillis();
        final AtomicBoolean done = new AtomicBoolean(false);
        final Object elt = impl.makeElement(1);
        final Future<?> f1, f2;
        final ExecutorService pool = Executors.newCachedThreadPool();
        try (PoolCleaner cleaner = cleaner(pool, done)) {
            final CountDownLatch threadsStarted = new CountDownLatch(2);
            Runnable checkElt = () -> {
                threadsStarted.countDown();
                while (!done.get())
                    c.stream().forEach((x) -> { assertSame(x, elt); }); };
            Runnable addRemove = () -> {
                threadsStarted.countDown();
                while (!done.get()) {
                    assertTrue(c.add(elt));
                    assertTrue(c.remove(elt));
                }};
            f1 = pool.submit(checkElt);
            f2 = pool.submit(addRemove);
            Thread.sleep(testDurationMillis);
        }
        assertNull(f1.get(0L, MILLISECONDS));
        assertNull(f2.get(0L, MILLISECONDS));
    }

    /**
     * collection.forEach returns elements in the collection
     */
    public void testForEach() throws Throwable {
        final Collection c = impl.emptyCollection();
        final AtomicLong count = new AtomicLong(0L);
        final Object x = impl.makeElement(1);
        final Object y = impl.makeElement(2);
        final ArrayList found = new ArrayList();
        Consumer<Object> spy = (o) -> { found.add(o); };
        c.forEach(spy);
        assertTrue(found.isEmpty());

        assertTrue(c.add(x));
        c.forEach(spy);
        assertEquals(Collections.singletonList(x), found);
        found.clear();

        assertTrue(c.add(y));
        c.forEach(spy);
        assertEquals(2, found.size());
        assertTrue(found.contains(x));
        assertTrue(found.contains(y));
        found.clear();

        c.clear();
        c.forEach(spy);
        assertTrue(found.isEmpty());
    }

    public void testForEachConcurrentStressTest() throws Throwable {
        if (!impl.isConcurrent()) return;
        final Collection c = impl.emptyCollection();
        final long testDurationMillis = timeoutMillis();
        final AtomicBoolean done = new AtomicBoolean(false);
        final Object elt = impl.makeElement(1);
        final Future<?> f1, f2;
        final ExecutorService pool = Executors.newCachedThreadPool();
        try (PoolCleaner cleaner = cleaner(pool, done)) {
            final CountDownLatch threadsStarted = new CountDownLatch(2);
            Runnable checkElt = () -> {
                threadsStarted.countDown();
                while (!done.get())
                    c.forEach((x) -> { assertSame(x, elt); }); };
            Runnable addRemove = () -> {
                threadsStarted.countDown();
                while (!done.get()) {
                    assertTrue(c.add(elt));
                    assertTrue(c.remove(elt));
                }};
            f1 = pool.submit(checkElt);
            f2 = pool.submit(addRemove);
            Thread.sleep(testDurationMillis);
        }
        assertNull(f1.get(0L, MILLISECONDS));
        assertNull(f2.get(0L, MILLISECONDS));
    }

//     public void testCollection8DebugFail() {
//         fail(impl.klazz().getSimpleName());
//     }
}
Revision:	1.9
Committed:	Thu Nov 3 16:53:13 2016 UTC (7 years, 6 months ago) by jsr166
Branch:	MAIN
Changes since 1.8:	+3 -0 lines
Log Message:	more assertions
#	User	Rev	Content
1	jsr166	1.1	/*
2			* Written by Doug Lea and Martin Buchholz with assistance from
3			* members of JCP JSR-166 Expert Group and released to the public
4			* domain, as explained at
5			* http://creativecommons.org/publicdomain/zero/1.0/
6			*/
7
8			import static java.util.concurrent.TimeUnit.MILLISECONDS;
9
10			import java.util.ArrayList;
11			import java.util.Collection;
12			import java.util.Collections;
13	jsr166	1.5	import java.util.Deque;
14			import java.util.HashSet;
15			import java.util.Iterator;
16			import java.util.List;
17			import java.util.NoSuchElementException;
18			import java.util.Queue;
19			import java.util.Spliterator;
20	jsr166	1.2	import java.util.concurrent.CountDownLatch;
21	jsr166	1.1	import java.util.concurrent.Executors;
22			import java.util.concurrent.ExecutorService;
23			import java.util.concurrent.Future;
24	jsr166	1.5	import java.util.concurrent.ThreadLocalRandom;
25	jsr166	1.1	import java.util.concurrent.atomic.AtomicBoolean;
26			import java.util.concurrent.atomic.AtomicLong;
27	jsr166	1.5	import java.util.concurrent.atomic.AtomicReference;
28	jsr166	1.1	import java.util.function.Consumer;
29	jsr166	1.5	import java.util.function.Predicate;
30	jsr166	1.1
31			import junit.framework.Test;
32
33			/**
34			* Contains tests applicable to all jdk8+ Collection implementations.
35			* An extension of CollectionTest.
36			*/
37			public class Collection8Test extends JSR166TestCase {
38			final CollectionImplementation impl;
39
40			/** Tests are parameterized by a Collection implementation. */
41			Collection8Test(CollectionImplementation impl, String methodName) {
42			super(methodName);
43			this.impl = impl;
44			}
45
46			public static Test testSuite(CollectionImplementation impl) {
47			return parameterizedTestSuite(Collection8Test.class,
48			CollectionImplementation.class,
49			impl);
50			}
51
52	jsr166	1.5	/** Checks properties of empty collections. */
53			public void testEmptyMeansEmpty() {
54			Collection c = impl.emptyCollection();
55			assertTrue(c.isEmpty());
56			assertEquals(0, c.size());
57			assertEquals("[]", c.toString());
58			{
59			Object[] a = c.toArray();
60			assertEquals(0, a.length);
61			assertSame(Object[].class, a.getClass());
62			}
63			{
64			Object[] a = new Object[0];
65			assertSame(a, c.toArray(a));
66			}
67			{
68			Integer[] a = new Integer[0];
69			assertSame(a, c.toArray(a));
70			}
71			{
72			Integer[] a = { 1, 2, 3};
73			assertSame(a, c.toArray(a));
74			assertNull(a[0]);
75			assertSame(2, a[1]);
76			assertSame(3, a[2]);
77			}
78			assertIteratorExhausted(c.iterator());
79			Consumer alwaysThrows = (e) -> { throw new AssertionError(); };
80			c.forEach(alwaysThrows);
81			c.iterator().forEachRemaining(alwaysThrows);
82			c.spliterator().forEachRemaining(alwaysThrows);
83			assertFalse(c.spliterator().tryAdvance(alwaysThrows));
84	jsr166	1.9	if (c.spliterator().hasCharacteristics(Spliterator.SIZED))
85			assertEquals(0, c.spliterator().estimateSize());
86	jsr166	1.5	if (Queue.class.isAssignableFrom(impl.klazz())) {
87			Queue q = (Queue) c;
88			assertNull(q.peek());
89			assertNull(q.poll());
90			}
91			if (Deque.class.isAssignableFrom(impl.klazz())) {
92			Deque d = (Deque) c;
93			assertNull(d.peekFirst());
94			assertNull(d.peekLast());
95			assertNull(d.pollFirst());
96			assertNull(d.pollLast());
97			assertIteratorExhausted(d.descendingIterator());
98	jsr166	1.9	d.descendingIterator().forEachRemaining(alwaysThrows);
99	jsr166	1.5	}
100			}
101
102			public void testNullPointerExceptions() {
103			Collection c = impl.emptyCollection();
104			assertThrows(
105			NullPointerException.class,
106			() -> c.addAll(null),
107			() -> c.containsAll(null),
108			() -> c.retainAll(null),
109			() -> c.removeAll(null),
110			() -> c.removeIf(null),
111	jsr166	1.6	() -> c.forEach(null),
112			() -> c.iterator().forEachRemaining(null),
113			() -> c.spliterator().forEachRemaining(null),
114			() -> c.spliterator().tryAdvance(null),
115	jsr166	1.5	() -> c.toArray(null));
116
117			if (!impl.permitsNulls()) {
118			assertThrows(
119			NullPointerException.class,
120			() -> c.add(null));
121			}
122			if (!impl.permitsNulls()
123			&& Queue.class.isAssignableFrom(impl.klazz())) {
124			Queue q = (Queue) c;
125			assertThrows(
126			NullPointerException.class,
127			() -> q.offer(null));
128			}
129			if (!impl.permitsNulls()
130			&& Deque.class.isAssignableFrom(impl.klazz())) {
131			Deque d = (Deque) c;
132			assertThrows(
133			NullPointerException.class,
134			() -> d.addFirst(null),
135			() -> d.addLast(null),
136			() -> d.offerFirst(null),
137			() -> d.offerLast(null),
138	jsr166	1.6	() -> d.push(null),
139			() -> d.descendingIterator().forEachRemaining(null));
140	jsr166	1.5	}
141			}
142
143			public void testNoSuchElementExceptions() {
144			Collection c = impl.emptyCollection();
145			assertThrows(
146			NoSuchElementException.class,
147			() -> c.iterator().next());
148
149			if (Queue.class.isAssignableFrom(impl.klazz())) {
150			Queue q = (Queue) c;
151			assertThrows(
152			NoSuchElementException.class,
153			() -> q.element(),
154			() -> q.remove());
155			}
156			if (Deque.class.isAssignableFrom(impl.klazz())) {
157			Deque d = (Deque) c;
158			assertThrows(
159			NoSuchElementException.class,
160			() -> d.getFirst(),
161			() -> d.getLast(),
162			() -> d.removeFirst(),
163			() -> d.removeLast(),
164			() -> d.pop(),
165			() -> d.descendingIterator().next());
166			}
167			}
168
169			public void testRemoveIf() {
170			Collection c = impl.emptyCollection();
171			ThreadLocalRandom rnd = ThreadLocalRandom.current();
172			int n = rnd.nextInt(6);
173			for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
174			AtomicReference threwAt = new AtomicReference(null);
175			ArrayList survivors = new ArrayList(c);
176			ArrayList accepts = new ArrayList();
177			ArrayList rejects = new ArrayList();
178			Predicate randomPredicate = (e) -> {
179			assertNull(threwAt.get());
180			switch (rnd.nextInt(3)) {
181			case 0: accepts.add(e); return true;
182			case 1: rejects.add(e); return false;
183			case 2: threwAt.set(e); throw new ArithmeticException();
184			default: throw new AssertionError();
185			}
186			};
187			try {
188	jsr166	1.8	assertFalse(survivors.contains(null));
189	jsr166	1.7	try {
190			boolean modified = c.removeIf(randomPredicate);
191			if (!modified) {
192			assertNull(threwAt.get());
193			assertEquals(n, rejects.size());
194			assertEquals(0, accepts.size());
195			}
196			} catch (ArithmeticException ok) {}
197			survivors.removeAll(accepts);
198			assertEquals(n - accepts.size(), c.size());
199			assertTrue(c.containsAll(survivors));
200			assertTrue(survivors.containsAll(rejects));
201			for (Object x : accepts) assertFalse(c.contains(x));
202			if (threwAt.get() == null)
203			assertEquals(accepts.size() + rejects.size(), n);
204			} catch (Throwable ex) {
205	jsr166	1.5	System.err.println(impl.klazz());
206	jsr166	1.7	System.err.printf("c=%s%n", c);
207			System.err.printf("n=%d%n", n);
208			System.err.printf("accepts=%s%n", accepts);
209			System.err.printf("rejects=%s%n", rejects);
210	jsr166	1.8	System.err.printf("survivors=%s%n", survivors);
211	jsr166	1.7	System.err.printf("threw=%s%n", threwAt.get());
212			throw ex;
213	jsr166	1.5	}
214			}
215
216			/**
217			* Various ways of traversing a collection yield same elements
218			*/
219			public void testIteratorEquivalence() {
220			Collection c = impl.emptyCollection();
221			ThreadLocalRandom rnd = ThreadLocalRandom.current();
222			int n = rnd.nextInt(6);
223			for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
224			ArrayList iterated = new ArrayList();
225			ArrayList iteratedForEachRemaining = new ArrayList();
226			ArrayList spliterated = new ArrayList();
227			ArrayList foreached = new ArrayList();
228			for (Object x : c) iterated.add(x);
229			c.iterator().forEachRemaining(e -> iteratedForEachRemaining.add(e));
230			c.spliterator().forEachRemaining(e -> spliterated.add(e));
231			c.forEach(e -> foreached.add(e));
232			boolean ordered =
233			c.spliterator().hasCharacteristics(Spliterator.ORDERED);
234			if (c instanceof List \|\| c instanceof Deque)
235			assertTrue(ordered);
236			if (ordered) {
237			assertEquals(iterated, iteratedForEachRemaining);
238			assertEquals(iterated, spliterated);
239			assertEquals(iterated, foreached);
240			} else {
241			HashSet cset = new HashSet(c);
242			assertEquals(cset, new HashSet(iterated));
243			assertEquals(cset, new HashSet(iteratedForEachRemaining));
244			assertEquals(cset, new HashSet(spliterated));
245			assertEquals(cset, new HashSet(foreached));
246			}
247			if (c instanceof Deque) {
248			Deque d = (Deque) c;
249			ArrayList descending = new ArrayList();
250			ArrayList descendingForEachRemaining = new ArrayList();
251			for (Iterator it = d.descendingIterator(); it.hasNext(); )
252			descending.add(it.next());
253			d.descendingIterator().forEachRemaining(
254			e -> descendingForEachRemaining.add(e));
255			Collections.reverse(descending);
256			Collections.reverse(descendingForEachRemaining);
257			assertEquals(iterated, descending);
258			assertEquals(iterated, descendingForEachRemaining);
259			}
260			}
261
262			/**
263			* Calling Iterator#remove() after Iterator#forEachRemaining
264			* should remove last element
265			*/
266			public void testRemoveAfterForEachRemaining() {
267			Collection c = impl.emptyCollection();
268			ThreadLocalRandom rnd = ThreadLocalRandom.current();
269			{
270			int n = 3 + rnd.nextInt(2);
271			for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
272			Iterator it = c.iterator();
273			assertTrue(it.hasNext());
274			assertEquals(impl.makeElement(0), it.next());
275			assertTrue(it.hasNext());
276			assertEquals(impl.makeElement(1), it.next());
277			it.forEachRemaining((e) -> {});
278			it.remove();
279			assertEquals(n - 1, c.size());
280			for (int i = 0; i < n - 1; i++)
281			assertTrue(c.contains(impl.makeElement(i)));
282			assertFalse(c.contains(impl.makeElement(n - 1)));
283			}
284			if (c instanceof Deque) {
285			Deque d = (Deque) impl.emptyCollection();
286			int n = 3 + rnd.nextInt(2);
287			for (int i = 0; i < n; i++) d.add(impl.makeElement(i));
288			Iterator it = d.descendingIterator();
289			assertTrue(it.hasNext());
290			assertEquals(impl.makeElement(n - 1), it.next());
291			assertTrue(it.hasNext());
292			assertEquals(impl.makeElement(n - 2), it.next());
293			it.forEachRemaining((e) -> {});
294			it.remove();
295			assertEquals(n - 1, d.size());
296			for (int i = 1; i < n; i++)
297			assertTrue(d.contains(impl.makeElement(i)));
298			assertFalse(d.contains(impl.makeElement(0)));
299			}
300			}
301
302	jsr166	1.1	/**
303			* stream().forEach returns elements in the collection
304			*/
305	jsr166	1.3	public void testStreamForEach() throws Throwable {
306	jsr166	1.1	final Collection c = impl.emptyCollection();
307			final AtomicLong count = new AtomicLong(0L);
308			final Object x = impl.makeElement(1);
309			final Object y = impl.makeElement(2);
310			final ArrayList found = new ArrayList();
311			Consumer<Object> spy = (o) -> { found.add(o); };
312			c.stream().forEach(spy);
313			assertTrue(found.isEmpty());
314
315			assertTrue(c.add(x));
316			c.stream().forEach(spy);
317			assertEquals(Collections.singletonList(x), found);
318			found.clear();
319
320			assertTrue(c.add(y));
321			c.stream().forEach(spy);
322			assertEquals(2, found.size());
323			assertTrue(found.contains(x));
324			assertTrue(found.contains(y));
325			found.clear();
326
327			c.clear();
328			c.stream().forEach(spy);
329			assertTrue(found.isEmpty());
330			}
331
332	jsr166	1.3	public void testStreamForEachConcurrentStressTest() throws Throwable {
333			if (!impl.isConcurrent()) return;
334			final Collection c = impl.emptyCollection();
335			final long testDurationMillis = timeoutMillis();
336			final AtomicBoolean done = new AtomicBoolean(false);
337			final Object elt = impl.makeElement(1);
338			final Future<?> f1, f2;
339			final ExecutorService pool = Executors.newCachedThreadPool();
340			try (PoolCleaner cleaner = cleaner(pool, done)) {
341			final CountDownLatch threadsStarted = new CountDownLatch(2);
342			Runnable checkElt = () -> {
343			threadsStarted.countDown();
344			while (!done.get())
345			c.stream().forEach((x) -> { assertSame(x, elt); }); };
346			Runnable addRemove = () -> {
347			threadsStarted.countDown();
348			while (!done.get()) {
349			assertTrue(c.add(elt));
350			assertTrue(c.remove(elt));
351			}};
352			f1 = pool.submit(checkElt);
353			f2 = pool.submit(addRemove);
354			Thread.sleep(testDurationMillis);
355			}
356			assertNull(f1.get(0L, MILLISECONDS));
357			assertNull(f2.get(0L, MILLISECONDS));
358			}
359
360			/**
361			* collection.forEach returns elements in the collection
362			*/
363			public void testForEach() throws Throwable {
364			final Collection c = impl.emptyCollection();
365			final AtomicLong count = new AtomicLong(0L);
366			final Object x = impl.makeElement(1);
367			final Object y = impl.makeElement(2);
368			final ArrayList found = new ArrayList();
369			Consumer<Object> spy = (o) -> { found.add(o); };
370			c.forEach(spy);
371			assertTrue(found.isEmpty());
372
373			assertTrue(c.add(x));
374			c.forEach(spy);
375			assertEquals(Collections.singletonList(x), found);
376			found.clear();
377
378			assertTrue(c.add(y));
379			c.forEach(spy);
380			assertEquals(2, found.size());
381			assertTrue(found.contains(x));
382			assertTrue(found.contains(y));
383			found.clear();
384
385			c.clear();
386			c.forEach(spy);
387			assertTrue(found.isEmpty());
388			}
389
390	jsr166	1.1	public void testForEachConcurrentStressTest() throws Throwable {
391			if (!impl.isConcurrent()) return;
392			final Collection c = impl.emptyCollection();
393	jsr166	1.2	final long testDurationMillis = timeoutMillis();
394	jsr166	1.1	final AtomicBoolean done = new AtomicBoolean(false);
395			final Object elt = impl.makeElement(1);
396	jsr166	1.2	final Future<?> f1, f2;
397			final ExecutorService pool = Executors.newCachedThreadPool();
398			try (PoolCleaner cleaner = cleaner(pool, done)) {
399			final CountDownLatch threadsStarted = new CountDownLatch(2);
400			Runnable checkElt = () -> {
401			threadsStarted.countDown();
402			while (!done.get())
403	jsr166	1.3	c.forEach((x) -> { assertSame(x, elt); }); };
404	jsr166	1.2	Runnable addRemove = () -> {
405			threadsStarted.countDown();
406			while (!done.get()) {
407			assertTrue(c.add(elt));
408			assertTrue(c.remove(elt));
409			}};
410			f1 = pool.submit(checkElt);
411			f2 = pool.submit(addRemove);
412			Thread.sleep(testDurationMillis);
413			}
414			assertNull(f1.get(0L, MILLISECONDS));
415			assertNull(f2.get(0L, MILLISECONDS));
416	jsr166	1.1	}
417
418	jsr166	1.4	// public void testCollection8DebugFail() {
419			// fail(impl.klazz().getSimpleName());
420			// }
421	jsr166	1.1	}