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

import java.util.ArrayList;
import java.util.Arrays;
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.BlockingDeque;
import java.util.concurrent.BlockingQueue;
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);
    }

    Object bomb() {
        return new Object() {
                public boolean equals(Object x) { throw new AssertionError(); }
                public int hashCode() { throw new AssertionError(); }
            };
    }

    /** Checks properties of empty collections. */
    public void testEmptyMeansEmpty() throws InterruptedException {
        Collection c = impl.emptyCollection();
        emptyMeansEmpty(c);

        if (c instanceof java.io.Serializable)
            emptyMeansEmpty(serialClone(c));

        Collection clone = cloneableClone(c);
        if (clone != null)
            emptyMeansEmpty(clone);
    }

    void emptyMeansEmpty(Collection c) throws InterruptedException {
        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());
        assertFalse(c.contains(bomb()));
        assertFalse(c.remove(bomb()));
        if (c instanceof Queue) {
            Queue q = (Queue) c;
            assertNull(q.peek());
            assertNull(q.poll());
        }
        if (c instanceof Deque) {
            Deque d = (Deque) c;
            assertNull(d.peekFirst());
            assertNull(d.peekLast());
            assertNull(d.pollFirst());
            assertNull(d.pollLast());
            assertIteratorExhausted(d.descendingIterator());
            d.descendingIterator().forEachRemaining(alwaysThrows);
            assertFalse(d.removeFirstOccurrence(bomb()));
            assertFalse(d.removeLastOccurrence(bomb()));
        }
        if (c instanceof BlockingQueue) {
            BlockingQueue q = (BlockingQueue) c;
            assertNull(q.poll(0L, MILLISECONDS));
        }
        if (c instanceof BlockingDeque) {
            BlockingDeque q = (BlockingDeque) c;
            assertNull(q.pollFirst(0L, MILLISECONDS));
            assertNull(q.pollLast(0L, MILLISECONDS));
        }
    }

    public void testNullPointerExceptions() throws InterruptedException {
        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() && c instanceof Queue) {
            Queue q = (Queue) c;
            assertThrows(
                NullPointerException.class,
                () -> q.offer(null));
        }
        if (!impl.permitsNulls() && c instanceof Deque) {
            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));
        }
        if (c instanceof BlockingQueue) {
            BlockingQueue q = (BlockingQueue) c;
            assertThrows(
                NullPointerException.class,
                () -> {
                    try { q.offer(null, 1L, HOURS); }
                    catch (InterruptedException ex) {
                        throw new AssertionError(ex);
                    }},
                () -> {
                    try { q.put(null); }
                    catch (InterruptedException ex) {
                        throw new AssertionError(ex);
                    }});
        }
        if (c instanceof BlockingDeque) {
            BlockingDeque q = (BlockingDeque) c;
            assertThrows(
                NullPointerException.class,
                () -> {
                    try { q.offerFirst(null, 1L, HOURS); }
                    catch (InterruptedException ex) {
                        throw new AssertionError(ex);
                    }},
                () -> {
                    try { q.offerLast(null, 1L, HOURS); }
                    catch (InterruptedException ex) {
                        throw new AssertionError(ex);
                    }},
                () -> {
                    try { q.putFirst(null); }
                    catch (InterruptedException ex) {
                        throw new AssertionError(ex);
                    }},
                () -> {
                    try { q.putLast(null); }
                    catch (InterruptedException ex) {
                        throw new AssertionError(ex);
                    }});
        }
    }

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

        if (c instanceof Queue) {
            Queue q = (Queue) c;
            assertThrows(
                NoSuchElementException.class,
                () -> q.element(),
                () -> q.remove());
        }
        if (c instanceof Deque) {
            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);
        List orig = rnd.nextBoolean()
            ? new ArrayList(c)
            : Arrays.asList(c.toArray());

        // Merely creating an iterator can change ArrayBlockingQueue behavior
        Iterator it = rnd.nextBoolean() ? c.iterator() : null;

        ArrayList survivors = new ArrayList();
        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 {
            try {
                boolean modified = c.removeIf(randomPredicate);
                assertNull(threwAt.get());
                assertEquals(modified, accepts.size() > 0);
                assertEquals(modified, rejects.size() != n);
                assertEquals(accepts.size() + rejects.size(), n);
                assertEquals(rejects, Arrays.asList(c.toArray()));
            } catch (ArithmeticException ok) {
                assertNotNull(threwAt.get());
                assertTrue(c.contains(threwAt.get()));
            }
            if (it != null && impl.isConcurrent())
                // check for weakly consistent iterator
                while (it.hasNext()) assertTrue(orig.contains(it.next()));
            switch (rnd.nextInt(4)) {
            case 0: survivors.addAll(c); break;
            case 1: survivors.addAll(Arrays.asList(c.toArray())); break;
            case 2: c.forEach(e -> survivors.add(e)); break;
            case 3: for (Object e : c) survivors.add(e); break;
            }
            assertTrue(orig.containsAll(accepts));
            assertTrue(orig.containsAll(rejects));
            assertTrue(orig.containsAll(survivors));
            assertTrue(orig.containsAll(c));
            assertTrue(c.containsAll(rejects));
            assertTrue(c.containsAll(survivors));
            assertTrue(survivors.containsAll(rejects));
            assertEquals(n - accepts.size(), c.size());
            for (Object x : accepts) assertFalse(c.contains(x));
        } 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("orig=%s%n", orig);
            System.err.printf("accepts=%s%n", accepts);
            System.err.printf("rejects=%s%n", rejects);
            System.err.printf("survivors=%s%n", survivors);
            System.err.printf("threwAt=%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 tryAdvanced = new ArrayList();
        ArrayList spliterated = new ArrayList();
        ArrayList forEached = new ArrayList();
        ArrayList removeIfed = new ArrayList();
        for (Object x : c) iterated.add(x);
        c.iterator().forEachRemaining(e -> iteratedForEachRemaining.add(e));
        for (Spliterator s = c.spliterator();
             s.tryAdvance(e -> tryAdvanced.add(e)); ) {}
        c.spliterator().forEachRemaining(e -> spliterated.add(e));
        c.forEach(e -> forEached.add(e));
        c.removeIf(e -> { removeIfed.add(e); return false; });
        boolean ordered =
            c.spliterator().hasCharacteristics(Spliterator.ORDERED);
        if (c instanceof List || c instanceof Deque)
            assertTrue(ordered);
        if (ordered) {
            assertEquals(iterated, iteratedForEachRemaining);
            assertEquals(iterated, tryAdvanced);
            assertEquals(iterated, spliterated);
            assertEquals(iterated, forEached);
            assertEquals(iterated, removeIfed);
        } else {
            HashSet cset = new HashSet(c);
            assertEquals(cset, new HashSet(iterated));
            assertEquals(cset, new HashSet(iteratedForEachRemaining));
            assertEquals(cset, new HashSet(tryAdvanced));
            assertEquals(cset, new HashSet(spliterated));
            assertEquals(cset, new HashSet(forEached));
            assertEquals(cset, new HashSet(removeIfed));
        }
        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:	1.18
Committed:	Sun Nov 6 20:53:53 2016 UTC (7 years, 6 months ago) by jsr166
Branch:	MAIN
Changes since 1.17:	+36 -12 lines
Log Message:	improve testRemoveIf
#	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	jsr166	1.16	import static java.util.concurrent.TimeUnit.HOURS;
9	jsr166	1.1	import static java.util.concurrent.TimeUnit.MILLISECONDS;
10
11			import java.util.ArrayList;
12	jsr166	1.18	import java.util.Arrays;
13	jsr166	1.1	import java.util.Collection;
14			import java.util.Collections;
15	jsr166	1.5	import java.util.Deque;
16			import java.util.HashSet;
17			import java.util.Iterator;
18			import java.util.List;
19			import java.util.NoSuchElementException;
20			import java.util.Queue;
21			import java.util.Spliterator;
22	jsr166	1.14	import java.util.concurrent.BlockingDeque;
23			import java.util.concurrent.BlockingQueue;
24	jsr166	1.2	import java.util.concurrent.CountDownLatch;
25	jsr166	1.1	import java.util.concurrent.Executors;
26			import java.util.concurrent.ExecutorService;
27			import java.util.concurrent.Future;
28	jsr166	1.5	import java.util.concurrent.ThreadLocalRandom;
29	jsr166	1.1	import java.util.concurrent.atomic.AtomicBoolean;
30			import java.util.concurrent.atomic.AtomicLong;
31	jsr166	1.5	import java.util.concurrent.atomic.AtomicReference;
32	jsr166	1.1	import java.util.function.Consumer;
33	jsr166	1.5	import java.util.function.Predicate;
34	jsr166	1.1
35			import junit.framework.Test;
36
37			/**
38			* Contains tests applicable to all jdk8+ Collection implementations.
39			* An extension of CollectionTest.
40			*/
41			public class Collection8Test extends JSR166TestCase {
42			final CollectionImplementation impl;
43
44			/** Tests are parameterized by a Collection implementation. */
45			Collection8Test(CollectionImplementation impl, String methodName) {
46			super(methodName);
47			this.impl = impl;
48			}
49
50			public static Test testSuite(CollectionImplementation impl) {
51			return parameterizedTestSuite(Collection8Test.class,
52			CollectionImplementation.class,
53			impl);
54			}
55
56	jsr166	1.10	Object bomb() {
57			return new Object() {
58			public boolean equals(Object x) { throw new AssertionError(); }
59			public int hashCode() { throw new AssertionError(); }
60			};
61			}
62
63	jsr166	1.5	/** Checks properties of empty collections. */
64	jsr166	1.14	public void testEmptyMeansEmpty() throws InterruptedException {
65	jsr166	1.5	Collection c = impl.emptyCollection();
66	jsr166	1.12	emptyMeansEmpty(c);
67
68			if (c instanceof java.io.Serializable)
69			emptyMeansEmpty(serialClone(c));
70
71			Collection clone = cloneableClone(c);
72			if (clone != null)
73			emptyMeansEmpty(clone);
74			}
75
76	jsr166	1.14	void emptyMeansEmpty(Collection c) throws InterruptedException {
77	jsr166	1.5	assertTrue(c.isEmpty());
78			assertEquals(0, c.size());
79			assertEquals("[]", c.toString());
80			{
81			Object[] a = c.toArray();
82			assertEquals(0, a.length);
83			assertSame(Object[].class, a.getClass());
84			}
85			{
86			Object[] a = new Object[0];
87			assertSame(a, c.toArray(a));
88			}
89			{
90			Integer[] a = new Integer[0];
91			assertSame(a, c.toArray(a));
92			}
93			{
94			Integer[] a = { 1, 2, 3};
95			assertSame(a, c.toArray(a));
96			assertNull(a[0]);
97			assertSame(2, a[1]);
98			assertSame(3, a[2]);
99			}
100			assertIteratorExhausted(c.iterator());
101			Consumer alwaysThrows = (e) -> { throw new AssertionError(); };
102			c.forEach(alwaysThrows);
103			c.iterator().forEachRemaining(alwaysThrows);
104			c.spliterator().forEachRemaining(alwaysThrows);
105			assertFalse(c.spliterator().tryAdvance(alwaysThrows));
106	jsr166	1.9	if (c.spliterator().hasCharacteristics(Spliterator.SIZED))
107			assertEquals(0, c.spliterator().estimateSize());
108	jsr166	1.10	assertFalse(c.contains(bomb()));
109			assertFalse(c.remove(bomb()));
110	jsr166	1.11	if (c instanceof Queue) {
111	jsr166	1.5	Queue q = (Queue) c;
112			assertNull(q.peek());
113			assertNull(q.poll());
114			}
115	jsr166	1.11	if (c instanceof Deque) {
116	jsr166	1.5	Deque d = (Deque) c;
117			assertNull(d.peekFirst());
118			assertNull(d.peekLast());
119			assertNull(d.pollFirst());
120			assertNull(d.pollLast());
121			assertIteratorExhausted(d.descendingIterator());
122	jsr166	1.9	d.descendingIterator().forEachRemaining(alwaysThrows);
123	jsr166	1.10	assertFalse(d.removeFirstOccurrence(bomb()));
124			assertFalse(d.removeLastOccurrence(bomb()));
125	jsr166	1.5	}
126	jsr166	1.14	if (c instanceof BlockingQueue) {
127			BlockingQueue q = (BlockingQueue) c;
128			assertNull(q.poll(0L, MILLISECONDS));
129			}
130			if (c instanceof BlockingDeque) {
131			BlockingDeque q = (BlockingDeque) c;
132			assertNull(q.pollFirst(0L, MILLISECONDS));
133			assertNull(q.pollLast(0L, MILLISECONDS));
134			}
135	jsr166	1.5	}
136
137	jsr166	1.14	public void testNullPointerExceptions() throws InterruptedException {
138	jsr166	1.5	Collection c = impl.emptyCollection();
139			assertThrows(
140			NullPointerException.class,
141			() -> c.addAll(null),
142			() -> c.containsAll(null),
143			() -> c.retainAll(null),
144			() -> c.removeAll(null),
145			() -> c.removeIf(null),
146	jsr166	1.6	() -> c.forEach(null),
147			() -> c.iterator().forEachRemaining(null),
148			() -> c.spliterator().forEachRemaining(null),
149			() -> c.spliterator().tryAdvance(null),
150	jsr166	1.5	() -> c.toArray(null));
151
152			if (!impl.permitsNulls()) {
153			assertThrows(
154			NullPointerException.class,
155			() -> c.add(null));
156			}
157	jsr166	1.14	if (!impl.permitsNulls() && c instanceof Queue) {
158	jsr166	1.5	Queue q = (Queue) c;
159			assertThrows(
160			NullPointerException.class,
161			() -> q.offer(null));
162			}
163	jsr166	1.14	if (!impl.permitsNulls() && c instanceof Deque) {
164	jsr166	1.5	Deque d = (Deque) c;
165			assertThrows(
166			NullPointerException.class,
167			() -> d.addFirst(null),
168			() -> d.addLast(null),
169			() -> d.offerFirst(null),
170			() -> d.offerLast(null),
171	jsr166	1.6	() -> d.push(null),
172			() -> d.descendingIterator().forEachRemaining(null));
173	jsr166	1.5	}
174	jsr166	1.15	if (c instanceof BlockingQueue) {
175	jsr166	1.14	BlockingQueue q = (BlockingQueue) c;
176			assertThrows(
177			NullPointerException.class,
178			() -> {
179	jsr166	1.16	try { q.offer(null, 1L, HOURS); }
180	jsr166	1.14	catch (InterruptedException ex) {
181			throw new AssertionError(ex);
182	jsr166	1.15	}},
183			() -> {
184			try { q.put(null); }
185			catch (InterruptedException ex) {
186			throw new AssertionError(ex);
187	jsr166	1.14	}});
188			}
189	jsr166	1.15	if (c instanceof BlockingDeque) {
190	jsr166	1.14	BlockingDeque q = (BlockingDeque) c;
191			assertThrows(
192			NullPointerException.class,
193			() -> {
194	jsr166	1.16	try { q.offerFirst(null, 1L, HOURS); }
195	jsr166	1.14	catch (InterruptedException ex) {
196			throw new AssertionError(ex);
197			}},
198			() -> {
199	jsr166	1.16	try { q.offerLast(null, 1L, HOURS); }
200	jsr166	1.14	catch (InterruptedException ex) {
201			throw new AssertionError(ex);
202	jsr166	1.15	}},
203			() -> {
204			try { q.putFirst(null); }
205			catch (InterruptedException ex) {
206			throw new AssertionError(ex);
207			}},
208			() -> {
209			try { q.putLast(null); }
210			catch (InterruptedException ex) {
211			throw new AssertionError(ex);
212	jsr166	1.14	}});
213			}
214	jsr166	1.5	}
215
216			public void testNoSuchElementExceptions() {
217			Collection c = impl.emptyCollection();
218			assertThrows(
219			NoSuchElementException.class,
220			() -> c.iterator().next());
221
222	jsr166	1.14	if (c instanceof Queue) {
223	jsr166	1.5	Queue q = (Queue) c;
224			assertThrows(
225			NoSuchElementException.class,
226			() -> q.element(),
227			() -> q.remove());
228			}
229	jsr166	1.14	if (c instanceof Deque) {
230	jsr166	1.5	Deque d = (Deque) c;
231			assertThrows(
232			NoSuchElementException.class,
233			() -> d.getFirst(),
234			() -> d.getLast(),
235			() -> d.removeFirst(),
236			() -> d.removeLast(),
237			() -> d.pop(),
238			() -> d.descendingIterator().next());
239			}
240			}
241
242			public void testRemoveIf() {
243			Collection c = impl.emptyCollection();
244			ThreadLocalRandom rnd = ThreadLocalRandom.current();
245			int n = rnd.nextInt(6);
246			for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
247			AtomicReference threwAt = new AtomicReference(null);
248	jsr166	1.18	List orig = rnd.nextBoolean()
249			? new ArrayList(c)
250			: Arrays.asList(c.toArray());
251
252			// Merely creating an iterator can change ArrayBlockingQueue behavior
253			Iterator it = rnd.nextBoolean() ? c.iterator() : null;
254
255			ArrayList survivors = new ArrayList();
256	jsr166	1.5	ArrayList accepts = new ArrayList();
257			ArrayList rejects = new ArrayList();
258	jsr166	1.18
259	jsr166	1.5	Predicate randomPredicate = (e) -> {
260			assertNull(threwAt.get());
261			switch (rnd.nextInt(3)) {
262			case 0: accepts.add(e); return true;
263			case 1: rejects.add(e); return false;
264			case 2: threwAt.set(e); throw new ArithmeticException();
265			default: throw new AssertionError();
266			}
267			};
268			try {
269	jsr166	1.7	try {
270			boolean modified = c.removeIf(randomPredicate);
271	jsr166	1.18	assertNull(threwAt.get());
272			assertEquals(modified, accepts.size() > 0);
273			assertEquals(modified, rejects.size() != n);
274			assertEquals(accepts.size() + rejects.size(), n);
275			assertEquals(rejects, Arrays.asList(c.toArray()));
276			} catch (ArithmeticException ok) {
277			assertNotNull(threwAt.get());
278			assertTrue(c.contains(threwAt.get()));
279			}
280			if (it != null && impl.isConcurrent())
281			// check for weakly consistent iterator
282			while (it.hasNext()) assertTrue(orig.contains(it.next()));
283			switch (rnd.nextInt(4)) {
284			case 0: survivors.addAll(c); break;
285			case 1: survivors.addAll(Arrays.asList(c.toArray())); break;
286			case 2: c.forEach(e -> survivors.add(e)); break;
287			case 3: for (Object e : c) survivors.add(e); break;
288			}
289			assertTrue(orig.containsAll(accepts));
290			assertTrue(orig.containsAll(rejects));
291			assertTrue(orig.containsAll(survivors));
292			assertTrue(orig.containsAll(c));
293			assertTrue(c.containsAll(rejects));
294	jsr166	1.7	assertTrue(c.containsAll(survivors));
295			assertTrue(survivors.containsAll(rejects));
296	jsr166	1.18	assertEquals(n - accepts.size(), c.size());
297	jsr166	1.7	for (Object x : accepts) assertFalse(c.contains(x));
298			} catch (Throwable ex) {
299	jsr166	1.5	System.err.println(impl.klazz());
300	jsr166	1.7	System.err.printf("c=%s%n", c);
301			System.err.printf("n=%d%n", n);
302	jsr166	1.18	System.err.printf("orig=%s%n", orig);
303	jsr166	1.7	System.err.printf("accepts=%s%n", accepts);
304			System.err.printf("rejects=%s%n", rejects);
305	jsr166	1.8	System.err.printf("survivors=%s%n", survivors);
306	jsr166	1.18	System.err.printf("threwAt=%s%n", threwAt.get());
307	jsr166	1.7	throw ex;
308	jsr166	1.5	}
309			}
310
311			/**
312			* Various ways of traversing a collection yield same elements
313			*/
314			public void testIteratorEquivalence() {
315			Collection c = impl.emptyCollection();
316			ThreadLocalRandom rnd = ThreadLocalRandom.current();
317			int n = rnd.nextInt(6);
318			for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
319			ArrayList iterated = new ArrayList();
320			ArrayList iteratedForEachRemaining = new ArrayList();
321	jsr166	1.13	ArrayList tryAdvanced = new ArrayList();
322	jsr166	1.5	ArrayList spliterated = new ArrayList();
323	jsr166	1.13	ArrayList forEached = new ArrayList();
324			ArrayList removeIfed = new ArrayList();
325	jsr166	1.5	for (Object x : c) iterated.add(x);
326			c.iterator().forEachRemaining(e -> iteratedForEachRemaining.add(e));
327	jsr166	1.13	for (Spliterator s = c.spliterator();
328			s.tryAdvance(e -> tryAdvanced.add(e)); ) {}
329	jsr166	1.5	c.spliterator().forEachRemaining(e -> spliterated.add(e));
330	jsr166	1.13	c.forEach(e -> forEached.add(e));
331			c.removeIf(e -> { removeIfed.add(e); return false; });
332	jsr166	1.5	boolean ordered =
333			c.spliterator().hasCharacteristics(Spliterator.ORDERED);
334			if (c instanceof List \|\| c instanceof Deque)
335			assertTrue(ordered);
336			if (ordered) {
337			assertEquals(iterated, iteratedForEachRemaining);
338	jsr166	1.13	assertEquals(iterated, tryAdvanced);
339	jsr166	1.5	assertEquals(iterated, spliterated);
340	jsr166	1.13	assertEquals(iterated, forEached);
341			assertEquals(iterated, removeIfed);
342	jsr166	1.5	} else {
343			HashSet cset = new HashSet(c);
344			assertEquals(cset, new HashSet(iterated));
345			assertEquals(cset, new HashSet(iteratedForEachRemaining));
346	jsr166	1.13	assertEquals(cset, new HashSet(tryAdvanced));
347	jsr166	1.5	assertEquals(cset, new HashSet(spliterated));
348	jsr166	1.13	assertEquals(cset, new HashSet(forEached));
349			assertEquals(cset, new HashSet(removeIfed));
350	jsr166	1.5	}
351			if (c instanceof Deque) {
352			Deque d = (Deque) c;
353			ArrayList descending = new ArrayList();
354			ArrayList descendingForEachRemaining = new ArrayList();
355			for (Iterator it = d.descendingIterator(); it.hasNext(); )
356			descending.add(it.next());
357			d.descendingIterator().forEachRemaining(
358			e -> descendingForEachRemaining.add(e));
359			Collections.reverse(descending);
360			Collections.reverse(descendingForEachRemaining);
361			assertEquals(iterated, descending);
362			assertEquals(iterated, descendingForEachRemaining);
363			}
364			}
365
366			/**
367			* Calling Iterator#remove() after Iterator#forEachRemaining
368			* should remove last element
369			*/
370			public void testRemoveAfterForEachRemaining() {
371			Collection c = impl.emptyCollection();
372			ThreadLocalRandom rnd = ThreadLocalRandom.current();
373			{
374			int n = 3 + rnd.nextInt(2);
375			for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
376			Iterator it = c.iterator();
377			assertTrue(it.hasNext());
378			assertEquals(impl.makeElement(0), it.next());
379			assertTrue(it.hasNext());
380			assertEquals(impl.makeElement(1), it.next());
381			it.forEachRemaining((e) -> {});
382			it.remove();
383			assertEquals(n - 1, c.size());
384			for (int i = 0; i < n - 1; i++)
385			assertTrue(c.contains(impl.makeElement(i)));
386			assertFalse(c.contains(impl.makeElement(n - 1)));
387			}
388			if (c instanceof Deque) {
389			Deque d = (Deque) impl.emptyCollection();
390			int n = 3 + rnd.nextInt(2);
391			for (int i = 0; i < n; i++) d.add(impl.makeElement(i));
392			Iterator it = d.descendingIterator();
393			assertTrue(it.hasNext());
394			assertEquals(impl.makeElement(n - 1), it.next());
395			assertTrue(it.hasNext());
396			assertEquals(impl.makeElement(n - 2), it.next());
397			it.forEachRemaining((e) -> {});
398			it.remove();
399			assertEquals(n - 1, d.size());
400			for (int i = 1; i < n; i++)
401			assertTrue(d.contains(impl.makeElement(i)));
402			assertFalse(d.contains(impl.makeElement(0)));
403			}
404			}
405
406	jsr166	1.1	/**
407			* stream().forEach returns elements in the collection
408			*/
409	jsr166	1.3	public void testStreamForEach() throws Throwable {
410	jsr166	1.1	final Collection c = impl.emptyCollection();
411			final AtomicLong count = new AtomicLong(0L);
412			final Object x = impl.makeElement(1);
413			final Object y = impl.makeElement(2);
414			final ArrayList found = new ArrayList();
415			Consumer<Object> spy = (o) -> { found.add(o); };
416			c.stream().forEach(spy);
417			assertTrue(found.isEmpty());
418
419			assertTrue(c.add(x));
420			c.stream().forEach(spy);
421			assertEquals(Collections.singletonList(x), found);
422			found.clear();
423
424			assertTrue(c.add(y));
425			c.stream().forEach(spy);
426			assertEquals(2, found.size());
427			assertTrue(found.contains(x));
428			assertTrue(found.contains(y));
429			found.clear();
430
431			c.clear();
432			c.stream().forEach(spy);
433			assertTrue(found.isEmpty());
434			}
435
436	jsr166	1.3	public void testStreamForEachConcurrentStressTest() throws Throwable {
437			if (!impl.isConcurrent()) return;
438			final Collection c = impl.emptyCollection();
439			final long testDurationMillis = timeoutMillis();
440			final AtomicBoolean done = new AtomicBoolean(false);
441			final Object elt = impl.makeElement(1);
442			final Future<?> f1, f2;
443			final ExecutorService pool = Executors.newCachedThreadPool();
444			try (PoolCleaner cleaner = cleaner(pool, done)) {
445			final CountDownLatch threadsStarted = new CountDownLatch(2);
446			Runnable checkElt = () -> {
447			threadsStarted.countDown();
448			while (!done.get())
449			c.stream().forEach((x) -> { assertSame(x, elt); }); };
450			Runnable addRemove = () -> {
451			threadsStarted.countDown();
452			while (!done.get()) {
453			assertTrue(c.add(elt));
454			assertTrue(c.remove(elt));
455			}};
456			f1 = pool.submit(checkElt);
457			f2 = pool.submit(addRemove);
458			Thread.sleep(testDurationMillis);
459			}
460			assertNull(f1.get(0L, MILLISECONDS));
461			assertNull(f2.get(0L, MILLISECONDS));
462			}
463
464			/**
465			* collection.forEach returns elements in the collection
466			*/
467			public void testForEach() throws Throwable {
468			final Collection c = impl.emptyCollection();
469			final AtomicLong count = new AtomicLong(0L);
470			final Object x = impl.makeElement(1);
471			final Object y = impl.makeElement(2);
472			final ArrayList found = new ArrayList();
473			Consumer<Object> spy = (o) -> { found.add(o); };
474			c.forEach(spy);
475			assertTrue(found.isEmpty());
476
477			assertTrue(c.add(x));
478			c.forEach(spy);
479			assertEquals(Collections.singletonList(x), found);
480			found.clear();
481
482			assertTrue(c.add(y));
483			c.forEach(spy);
484			assertEquals(2, found.size());
485			assertTrue(found.contains(x));
486			assertTrue(found.contains(y));
487			found.clear();
488
489			c.clear();
490			c.forEach(spy);
491			assertTrue(found.isEmpty());
492			}
493
494	jsr166	1.1	public void testForEachConcurrentStressTest() throws Throwable {
495			if (!impl.isConcurrent()) return;
496			final Collection c = impl.emptyCollection();
497	jsr166	1.2	final long testDurationMillis = timeoutMillis();
498	jsr166	1.1	final AtomicBoolean done = new AtomicBoolean(false);
499			final Object elt = impl.makeElement(1);
500	jsr166	1.2	final Future<?> f1, f2;
501			final ExecutorService pool = Executors.newCachedThreadPool();
502			try (PoolCleaner cleaner = cleaner(pool, done)) {
503			final CountDownLatch threadsStarted = new CountDownLatch(2);
504			Runnable checkElt = () -> {
505			threadsStarted.countDown();
506			while (!done.get())
507	jsr166	1.3	c.forEach((x) -> { assertSame(x, elt); }); };
508	jsr166	1.2	Runnable addRemove = () -> {
509			threadsStarted.countDown();
510			while (!done.get()) {
511			assertTrue(c.add(elt));
512			assertTrue(c.remove(elt));
513			}};
514			f1 = pool.submit(checkElt);
515			f2 = pool.submit(addRemove);
516			Thread.sleep(testDurationMillis);
517			}
518			assertNull(f1.get(0L, MILLISECONDS));
519			assertNull(f2.get(0L, MILLISECONDS));
520	jsr166	1.1	}
521
522	jsr166	1.4	// public void testCollection8DebugFail() {
523			// fail(impl.klazz().getSimpleName());
524			// }
525	jsr166	1.1	}