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 Throwable {
        Collection c = impl.emptyCollection();
        emptyMeansEmpty(c);

        if (c instanceof java.io.Serializable) {
            try {
                emptyMeansEmpty(serialClonePossiblyFailing(c));
            } catch (java.io.NotSerializableException ex) {
                // excusable when we have a serializable wrapper around
                // a non-serializable collection, as can happen with:
                // Vector.subList() => wrapped AbstractList$RandomAccessSubList
                if (testImplementationDetails
                    && (! c.getClass().getName().matches(
                                "java.util.Collections.*")))
                    throw ex;
            }
        }

        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();
        boolean ordered =
            c.spliterator().hasCharacteristics(Spliterator.ORDERED);
        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);
                if (ordered) {
                    assertEquals(rejects,
                                 Arrays.asList(c.toArray()));
                } else {
                    assertEquals(new HashSet(rejects),
                                 new HashSet(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));
            if (threwAt.get() == null) {
                assertEquals(n - accepts.size(), c.size());
                for (Object x : accepts) assertFalse(c.contains(x));
            } else {
                // Two acceptable behaviors: entire removeIf call is one
                // transaction, or each element processed is one transaction.
                assertTrue(n == c.size() || n == c.size() + accepts.size());
                int k = 0;
                for (Object x : accepts) if (c.contains(x)) k++;
                assertTrue(k == accepts.size() || k == 0);
            }
        } catch (Throwable ex) {
            System.err.println(impl.klazz());
            // c is at risk of corruption if we got here, so be lenient
            try { System.err.printf("c=%s%n", c); }
            catch (Throwable t) { t.printStackTrace(); }
            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 (maybe) remove last element
     */
    public void testRemoveAfterForEachRemaining() {
        Collection c = impl.emptyCollection();
        ThreadLocalRandom rnd = ThreadLocalRandom.current();
        testCollection: {
            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 -> assertTrue(c.contains(e)));
            if (testImplementationDetails) {
                if (c instanceof java.util.concurrent.ArrayBlockingQueue) {
                    assertIteratorExhausted(it);
                } else {
                    try { it.remove(); }
                    catch (UnsupportedOperationException ok) {
                        break testCollection;
                    }
                    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 -> assertTrue(c.contains(e)));
            if (testImplementationDetails) {
                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:	1.25
Committed:	Tue Nov 15 00:08:25 2016 UTC (7 years, 5 months ago) by jsr166
Branch:	MAIN
Changes since 1.24:	+5 -2 lines
Log Message:	add CopyOnWriteArrayList generic Collection tests
#	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	1.24	public void testEmptyMeansEmpty() throws Throwable {
65	jsr166	1.5	Collection c = impl.emptyCollection();
66	jsr166	1.12	emptyMeansEmpty(c);
67
68	jsr166	1.24	if (c instanceof java.io.Serializable) {
69			try {
70			emptyMeansEmpty(serialClonePossiblyFailing(c));
71			} catch (java.io.NotSerializableException ex) {
72			// excusable when we have a serializable wrapper around
73			// a non-serializable collection, as can happen with:
74			// Vector.subList() => wrapped AbstractList$RandomAccessSubList
75			if (testImplementationDetails
76			&& (! c.getClass().getName().matches(
77			"java.util.Collections.*")))
78			throw ex;
79			}
80			}
81	jsr166	1.12
82			Collection clone = cloneableClone(c);
83			if (clone != null)
84			emptyMeansEmpty(clone);
85			}
86
87	jsr166	1.14	void emptyMeansEmpty(Collection c) throws InterruptedException {
88	jsr166	1.5	assertTrue(c.isEmpty());
89			assertEquals(0, c.size());
90			assertEquals("[]", c.toString());
91			{
92			Object[] a = c.toArray();
93			assertEquals(0, a.length);
94			assertSame(Object[].class, a.getClass());
95			}
96			{
97			Object[] a = new Object[0];
98			assertSame(a, c.toArray(a));
99			}
100			{
101			Integer[] a = new Integer[0];
102			assertSame(a, c.toArray(a));
103			}
104			{
105			Integer[] a = { 1, 2, 3};
106			assertSame(a, c.toArray(a));
107			assertNull(a[0]);
108			assertSame(2, a[1]);
109			assertSame(3, a[2]);
110			}
111			assertIteratorExhausted(c.iterator());
112	jsr166	1.19	Consumer alwaysThrows = e -> { throw new AssertionError(); };
113	jsr166	1.5	c.forEach(alwaysThrows);
114			c.iterator().forEachRemaining(alwaysThrows);
115			c.spliterator().forEachRemaining(alwaysThrows);
116			assertFalse(c.spliterator().tryAdvance(alwaysThrows));
117	jsr166	1.9	if (c.spliterator().hasCharacteristics(Spliterator.SIZED))
118			assertEquals(0, c.spliterator().estimateSize());
119	jsr166	1.10	assertFalse(c.contains(bomb()));
120			assertFalse(c.remove(bomb()));
121	jsr166	1.11	if (c instanceof Queue) {
122	jsr166	1.5	Queue q = (Queue) c;
123			assertNull(q.peek());
124			assertNull(q.poll());
125			}
126	jsr166	1.11	if (c instanceof Deque) {
127	jsr166	1.5	Deque d = (Deque) c;
128			assertNull(d.peekFirst());
129			assertNull(d.peekLast());
130			assertNull(d.pollFirst());
131			assertNull(d.pollLast());
132			assertIteratorExhausted(d.descendingIterator());
133	jsr166	1.9	d.descendingIterator().forEachRemaining(alwaysThrows);
134	jsr166	1.10	assertFalse(d.removeFirstOccurrence(bomb()));
135			assertFalse(d.removeLastOccurrence(bomb()));
136	jsr166	1.5	}
137	jsr166	1.14	if (c instanceof BlockingQueue) {
138			BlockingQueue q = (BlockingQueue) c;
139			assertNull(q.poll(0L, MILLISECONDS));
140			}
141			if (c instanceof BlockingDeque) {
142			BlockingDeque q = (BlockingDeque) c;
143			assertNull(q.pollFirst(0L, MILLISECONDS));
144			assertNull(q.pollLast(0L, MILLISECONDS));
145			}
146	jsr166	1.5	}
147
148	jsr166	1.14	public void testNullPointerExceptions() throws InterruptedException {
149	jsr166	1.5	Collection c = impl.emptyCollection();
150			assertThrows(
151			NullPointerException.class,
152			() -> c.addAll(null),
153			() -> c.containsAll(null),
154			() -> c.retainAll(null),
155			() -> c.removeAll(null),
156			() -> c.removeIf(null),
157	jsr166	1.6	() -> c.forEach(null),
158			() -> c.iterator().forEachRemaining(null),
159			() -> c.spliterator().forEachRemaining(null),
160			() -> c.spliterator().tryAdvance(null),
161	jsr166	1.5	() -> c.toArray(null));
162
163			if (!impl.permitsNulls()) {
164			assertThrows(
165			NullPointerException.class,
166			() -> c.add(null));
167			}
168	jsr166	1.14	if (!impl.permitsNulls() && c instanceof Queue) {
169	jsr166	1.5	Queue q = (Queue) c;
170			assertThrows(
171			NullPointerException.class,
172			() -> q.offer(null));
173			}
174	jsr166	1.14	if (!impl.permitsNulls() && c instanceof Deque) {
175	jsr166	1.5	Deque d = (Deque) c;
176			assertThrows(
177			NullPointerException.class,
178			() -> d.addFirst(null),
179			() -> d.addLast(null),
180			() -> d.offerFirst(null),
181			() -> d.offerLast(null),
182	jsr166	1.6	() -> d.push(null),
183			() -> d.descendingIterator().forEachRemaining(null));
184	jsr166	1.5	}
185	jsr166	1.15	if (c instanceof BlockingQueue) {
186	jsr166	1.14	BlockingQueue q = (BlockingQueue) c;
187			assertThrows(
188			NullPointerException.class,
189			() -> {
190	jsr166	1.16	try { q.offer(null, 1L, HOURS); }
191	jsr166	1.14	catch (InterruptedException ex) {
192			throw new AssertionError(ex);
193	jsr166	1.15	}},
194			() -> {
195			try { q.put(null); }
196			catch (InterruptedException ex) {
197			throw new AssertionError(ex);
198	jsr166	1.14	}});
199			}
200	jsr166	1.15	if (c instanceof BlockingDeque) {
201	jsr166	1.14	BlockingDeque q = (BlockingDeque) c;
202			assertThrows(
203			NullPointerException.class,
204			() -> {
205	jsr166	1.16	try { q.offerFirst(null, 1L, HOURS); }
206	jsr166	1.14	catch (InterruptedException ex) {
207			throw new AssertionError(ex);
208			}},
209			() -> {
210	jsr166	1.16	try { q.offerLast(null, 1L, HOURS); }
211	jsr166	1.14	catch (InterruptedException ex) {
212			throw new AssertionError(ex);
213	jsr166	1.15	}},
214			() -> {
215			try { q.putFirst(null); }
216			catch (InterruptedException ex) {
217			throw new AssertionError(ex);
218			}},
219			() -> {
220			try { q.putLast(null); }
221			catch (InterruptedException ex) {
222			throw new AssertionError(ex);
223	jsr166	1.14	}});
224			}
225	jsr166	1.5	}
226
227			public void testNoSuchElementExceptions() {
228			Collection c = impl.emptyCollection();
229			assertThrows(
230			NoSuchElementException.class,
231			() -> c.iterator().next());
232
233	jsr166	1.14	if (c instanceof Queue) {
234	jsr166	1.5	Queue q = (Queue) c;
235			assertThrows(
236			NoSuchElementException.class,
237			() -> q.element(),
238			() -> q.remove());
239			}
240	jsr166	1.14	if (c instanceof Deque) {
241	jsr166	1.5	Deque d = (Deque) c;
242			assertThrows(
243			NoSuchElementException.class,
244			() -> d.getFirst(),
245			() -> d.getLast(),
246			() -> d.removeFirst(),
247			() -> d.removeLast(),
248			() -> d.pop(),
249			() -> d.descendingIterator().next());
250			}
251			}
252
253			public void testRemoveIf() {
254			Collection c = impl.emptyCollection();
255	jsr166	1.22	boolean ordered =
256			c.spliterator().hasCharacteristics(Spliterator.ORDERED);
257	jsr166	1.5	ThreadLocalRandom rnd = ThreadLocalRandom.current();
258			int n = rnd.nextInt(6);
259			for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
260			AtomicReference threwAt = new AtomicReference(null);
261	jsr166	1.18	List orig = rnd.nextBoolean()
262			? new ArrayList(c)
263			: Arrays.asList(c.toArray());
264
265			// Merely creating an iterator can change ArrayBlockingQueue behavior
266			Iterator it = rnd.nextBoolean() ? c.iterator() : null;
267
268			ArrayList survivors = new ArrayList();
269	jsr166	1.5	ArrayList accepts = new ArrayList();
270			ArrayList rejects = new ArrayList();
271	jsr166	1.18
272	jsr166	1.19	Predicate randomPredicate = e -> {
273	jsr166	1.5	assertNull(threwAt.get());
274			switch (rnd.nextInt(3)) {
275			case 0: accepts.add(e); return true;
276			case 1: rejects.add(e); return false;
277			case 2: threwAt.set(e); throw new ArithmeticException();
278			default: throw new AssertionError();
279			}
280			};
281			try {
282	jsr166	1.7	try {
283			boolean modified = c.removeIf(randomPredicate);
284	jsr166	1.18	assertNull(threwAt.get());
285			assertEquals(modified, accepts.size() > 0);
286			assertEquals(modified, rejects.size() != n);
287			assertEquals(accepts.size() + rejects.size(), n);
288	jsr166	1.22	if (ordered) {
289			assertEquals(rejects,
290			Arrays.asList(c.toArray()));
291			} else {
292			assertEquals(new HashSet(rejects),
293			new HashSet(Arrays.asList(c.toArray())));
294			}
295	jsr166	1.18	} catch (ArithmeticException ok) {
296			assertNotNull(threwAt.get());
297			assertTrue(c.contains(threwAt.get()));
298			}
299			if (it != null && impl.isConcurrent())
300			// check for weakly consistent iterator
301			while (it.hasNext()) assertTrue(orig.contains(it.next()));
302			switch (rnd.nextInt(4)) {
303			case 0: survivors.addAll(c); break;
304			case 1: survivors.addAll(Arrays.asList(c.toArray())); break;
305			case 2: c.forEach(e -> survivors.add(e)); break;
306			case 3: for (Object e : c) survivors.add(e); break;
307			}
308			assertTrue(orig.containsAll(accepts));
309			assertTrue(orig.containsAll(rejects));
310			assertTrue(orig.containsAll(survivors));
311			assertTrue(orig.containsAll(c));
312			assertTrue(c.containsAll(rejects));
313	jsr166	1.7	assertTrue(c.containsAll(survivors));
314			assertTrue(survivors.containsAll(rejects));
315	jsr166	1.22	if (threwAt.get() == null) {
316			assertEquals(n - accepts.size(), c.size());
317			for (Object x : accepts) assertFalse(c.contains(x));
318			} else {
319			// Two acceptable behaviors: entire removeIf call is one
320			// transaction, or each element processed is one transaction.
321			assertTrue(n == c.size() \|\| n == c.size() + accepts.size());
322			int k = 0;
323			for (Object x : accepts) if (c.contains(x)) k++;
324			assertTrue(k == accepts.size() \|\| k == 0);
325			}
326	jsr166	1.7	} catch (Throwable ex) {
327	jsr166	1.5	System.err.println(impl.klazz());
328	jsr166	1.23	// c is at risk of corruption if we got here, so be lenient
329			try { System.err.printf("c=%s%n", c); }
330			catch (Throwable t) { t.printStackTrace(); }
331	jsr166	1.7	System.err.printf("n=%d%n", n);
332	jsr166	1.18	System.err.printf("orig=%s%n", orig);
333	jsr166	1.7	System.err.printf("accepts=%s%n", accepts);
334			System.err.printf("rejects=%s%n", rejects);
335	jsr166	1.8	System.err.printf("survivors=%s%n", survivors);
336	jsr166	1.18	System.err.printf("threwAt=%s%n", threwAt.get());
337	jsr166	1.7	throw ex;
338	jsr166	1.5	}
339			}
340
341			/**
342			* Various ways of traversing a collection yield same elements
343			*/
344			public void testIteratorEquivalence() {
345			Collection c = impl.emptyCollection();
346			ThreadLocalRandom rnd = ThreadLocalRandom.current();
347			int n = rnd.nextInt(6);
348			for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
349			ArrayList iterated = new ArrayList();
350			ArrayList iteratedForEachRemaining = new ArrayList();
351	jsr166	1.13	ArrayList tryAdvanced = new ArrayList();
352	jsr166	1.5	ArrayList spliterated = new ArrayList();
353	jsr166	1.13	ArrayList forEached = new ArrayList();
354			ArrayList removeIfed = new ArrayList();
355	jsr166	1.5	for (Object x : c) iterated.add(x);
356			c.iterator().forEachRemaining(e -> iteratedForEachRemaining.add(e));
357	jsr166	1.13	for (Spliterator s = c.spliterator();
358			s.tryAdvance(e -> tryAdvanced.add(e)); ) {}
359	jsr166	1.5	c.spliterator().forEachRemaining(e -> spliterated.add(e));
360	jsr166	1.13	c.forEach(e -> forEached.add(e));
361			c.removeIf(e -> { removeIfed.add(e); return false; });
362	jsr166	1.5	boolean ordered =
363			c.spliterator().hasCharacteristics(Spliterator.ORDERED);
364			if (c instanceof List \|\| c instanceof Deque)
365			assertTrue(ordered);
366			if (ordered) {
367			assertEquals(iterated, iteratedForEachRemaining);
368	jsr166	1.13	assertEquals(iterated, tryAdvanced);
369	jsr166	1.5	assertEquals(iterated, spliterated);
370	jsr166	1.13	assertEquals(iterated, forEached);
371			assertEquals(iterated, removeIfed);
372	jsr166	1.5	} else {
373			HashSet cset = new HashSet(c);
374			assertEquals(cset, new HashSet(iterated));
375			assertEquals(cset, new HashSet(iteratedForEachRemaining));
376	jsr166	1.13	assertEquals(cset, new HashSet(tryAdvanced));
377	jsr166	1.5	assertEquals(cset, new HashSet(spliterated));
378	jsr166	1.13	assertEquals(cset, new HashSet(forEached));
379			assertEquals(cset, new HashSet(removeIfed));
380	jsr166	1.5	}
381			if (c instanceof Deque) {
382			Deque d = (Deque) c;
383			ArrayList descending = new ArrayList();
384			ArrayList descendingForEachRemaining = new ArrayList();
385			for (Iterator it = d.descendingIterator(); it.hasNext(); )
386			descending.add(it.next());
387			d.descendingIterator().forEachRemaining(
388			e -> descendingForEachRemaining.add(e));
389			Collections.reverse(descending);
390			Collections.reverse(descendingForEachRemaining);
391			assertEquals(iterated, descending);
392			assertEquals(iterated, descendingForEachRemaining);
393			}
394			}
395
396			/**
397			* Calling Iterator#remove() after Iterator#forEachRemaining
398	jsr166	1.21	* should (maybe) remove last element
399	jsr166	1.5	*/
400			public void testRemoveAfterForEachRemaining() {
401			Collection c = impl.emptyCollection();
402			ThreadLocalRandom rnd = ThreadLocalRandom.current();
403	jsr166	1.25	testCollection: {
404	jsr166	1.5	int n = 3 + rnd.nextInt(2);
405			for (int i = 0; i < n; i++) c.add(impl.makeElement(i));
406			Iterator it = c.iterator();
407			assertTrue(it.hasNext());
408			assertEquals(impl.makeElement(0), it.next());
409			assertTrue(it.hasNext());
410			assertEquals(impl.makeElement(1), it.next());
411	jsr166	1.21	it.forEachRemaining(e -> assertTrue(c.contains(e)));
412			if (testImplementationDetails) {
413			if (c instanceof java.util.concurrent.ArrayBlockingQueue) {
414			assertIteratorExhausted(it);
415			} else {
416	jsr166	1.25	try { it.remove(); }
417			catch (UnsupportedOperationException ok) {
418			break testCollection;
419			}
420	jsr166	1.21	assertEquals(n - 1, c.size());
421			for (int i = 0; i < n - 1; i++)
422			assertTrue(c.contains(impl.makeElement(i)));
423			assertFalse(c.contains(impl.makeElement(n - 1)));
424			}
425			}
426	jsr166	1.5	}
427			if (c instanceof Deque) {
428			Deque d = (Deque) impl.emptyCollection();
429			int n = 3 + rnd.nextInt(2);
430			for (int i = 0; i < n; i++) d.add(impl.makeElement(i));
431			Iterator it = d.descendingIterator();
432			assertTrue(it.hasNext());
433			assertEquals(impl.makeElement(n - 1), it.next());
434			assertTrue(it.hasNext());
435			assertEquals(impl.makeElement(n - 2), it.next());
436	jsr166	1.21	it.forEachRemaining(e -> assertTrue(c.contains(e)));
437			if (testImplementationDetails) {
438			it.remove();
439			assertEquals(n - 1, d.size());
440			for (int i = 1; i < n; i++)
441			assertTrue(d.contains(impl.makeElement(i)));
442			assertFalse(d.contains(impl.makeElement(0)));
443			}
444	jsr166	1.5	}
445			}
446
447	jsr166	1.1	/**
448			* stream().forEach returns elements in the collection
449			*/
450	jsr166	1.3	public void testStreamForEach() throws Throwable {
451	jsr166	1.1	final Collection c = impl.emptyCollection();
452			final AtomicLong count = new AtomicLong(0L);
453			final Object x = impl.makeElement(1);
454			final Object y = impl.makeElement(2);
455			final ArrayList found = new ArrayList();
456	jsr166	1.20	Consumer<Object> spy = o -> found.add(o);
457	jsr166	1.1	c.stream().forEach(spy);
458			assertTrue(found.isEmpty());
459
460			assertTrue(c.add(x));
461			c.stream().forEach(spy);
462			assertEquals(Collections.singletonList(x), found);
463			found.clear();
464
465			assertTrue(c.add(y));
466			c.stream().forEach(spy);
467			assertEquals(2, found.size());
468			assertTrue(found.contains(x));
469			assertTrue(found.contains(y));
470			found.clear();
471
472			c.clear();
473			c.stream().forEach(spy);
474			assertTrue(found.isEmpty());
475			}
476
477	jsr166	1.3	public void testStreamForEachConcurrentStressTest() throws Throwable {
478			if (!impl.isConcurrent()) return;
479			final Collection c = impl.emptyCollection();
480			final long testDurationMillis = timeoutMillis();
481			final AtomicBoolean done = new AtomicBoolean(false);
482			final Object elt = impl.makeElement(1);
483			final Future<?> f1, f2;
484			final ExecutorService pool = Executors.newCachedThreadPool();
485			try (PoolCleaner cleaner = cleaner(pool, done)) {
486			final CountDownLatch threadsStarted = new CountDownLatch(2);
487			Runnable checkElt = () -> {
488			threadsStarted.countDown();
489			while (!done.get())
490	jsr166	1.20	c.stream().forEach(x -> assertSame(x, elt)); };
491	jsr166	1.3	Runnable addRemove = () -> {
492			threadsStarted.countDown();
493			while (!done.get()) {
494			assertTrue(c.add(elt));
495			assertTrue(c.remove(elt));
496			}};
497			f1 = pool.submit(checkElt);
498			f2 = pool.submit(addRemove);
499			Thread.sleep(testDurationMillis);
500			}
501			assertNull(f1.get(0L, MILLISECONDS));
502			assertNull(f2.get(0L, MILLISECONDS));
503			}
504
505			/**
506			* collection.forEach returns elements in the collection
507			*/
508			public void testForEach() throws Throwable {
509			final Collection c = impl.emptyCollection();
510			final AtomicLong count = new AtomicLong(0L);
511			final Object x = impl.makeElement(1);
512			final Object y = impl.makeElement(2);
513			final ArrayList found = new ArrayList();
514	jsr166	1.20	Consumer<Object> spy = o -> found.add(o);
515	jsr166	1.3	c.forEach(spy);
516			assertTrue(found.isEmpty());
517
518			assertTrue(c.add(x));
519			c.forEach(spy);
520			assertEquals(Collections.singletonList(x), found);
521			found.clear();
522
523			assertTrue(c.add(y));
524			c.forEach(spy);
525			assertEquals(2, found.size());
526			assertTrue(found.contains(x));
527			assertTrue(found.contains(y));
528			found.clear();
529
530			c.clear();
531			c.forEach(spy);
532			assertTrue(found.isEmpty());
533			}
534
535	jsr166	1.1	public void testForEachConcurrentStressTest() throws Throwable {
536			if (!impl.isConcurrent()) return;
537			final Collection c = impl.emptyCollection();
538	jsr166	1.2	final long testDurationMillis = timeoutMillis();
539	jsr166	1.1	final AtomicBoolean done = new AtomicBoolean(false);
540			final Object elt = impl.makeElement(1);
541	jsr166	1.2	final Future<?> f1, f2;
542			final ExecutorService pool = Executors.newCachedThreadPool();
543			try (PoolCleaner cleaner = cleaner(pool, done)) {
544			final CountDownLatch threadsStarted = new CountDownLatch(2);
545			Runnable checkElt = () -> {
546			threadsStarted.countDown();
547			while (!done.get())
548	jsr166	1.20	c.forEach(x -> assertSame(x, elt)); };
549	jsr166	1.2	Runnable addRemove = () -> {
550			threadsStarted.countDown();
551			while (!done.get()) {
552			assertTrue(c.add(elt));
553			assertTrue(c.remove(elt));
554			}};
555			f1 = pool.submit(checkElt);
556			f2 = pool.submit(addRemove);
557			Thread.sleep(testDurationMillis);
558			}
559			assertNull(f1.get(0L, MILLISECONDS));
560			assertNull(f2.get(0L, MILLISECONDS));
561	jsr166	1.1	}
562
563	jsr166	1.4	// public void testCollection8DebugFail() {
564			// fail(impl.klazz().getSimpleName());
565			// }
566	jsr166	1.1	}