--- jsr166/src/test/tck/SynchronousQueueTest.java	2003/09/07 20:39:11	1.2
+++ jsr166/src/test/tck/SynchronousQueueTest.java	2015/10/04 18:28:51	1.49
@@ -1,463 +1,615 @@
 /*
- * Written by members of JCP JSR-166 Expert Group and released to the
- * public domain. Use, modify, and redistribute this code in any way
- * without acknowledgement. Other contributors include Andrew Wright,
- * Jeffrey Hayes, Pat Fischer, Mike Judd.
+ * Written by Doug Lea 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/
+ * Other contributors include Andrew Wright, Jeffrey Hayes,
+ * Pat Fisher, Mike Judd.
  */
 
-import junit.framework.*;
-import java.util.*;
-import java.util.concurrent.*;
-import java.io.*;
-
-public class SynchronousQueueTest extends TestCase {
-
-    private final static int N = 1;
-    private static long SHORT_DELAY_MS = 100; 
-    private static long MEDIUM_DELAY_MS = 1000;
-    private static long LONG_DELAY_MS = 10000; 
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
 
-    public static void main(String[] args) {
-	junit.textui.TestRunner.run (suite());	
-    }
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.SynchronousQueue;
 
-    public static Test suite() {
-	return new TestSuite(SynchronousQueueTest.class);
-    }
+import junit.framework.Test;
 
-    public void testEmptyFull() {
-        SynchronousQueue q = new SynchronousQueue();
-        assertTrue(q.isEmpty());
-	assertEquals(0, q.size());
-        assertEquals(0, q.remainingCapacity());
-        assertFalse(q.offer(new Integer(3)));
-    }
-
-    public void testOfferNull(){
-	try {
-            SynchronousQueue q = new SynchronousQueue();
-            q.offer(null);
-            fail("should throw NPE");
-        } catch (NullPointerException success) { }   
-    }
-
-    public void testOffer(){
-        SynchronousQueue q = new SynchronousQueue();
-        assertFalse(q.offer(new Integer(1)));
-    }
-
-    public void testAdd(){
-	try {
-            SynchronousQueue q = new SynchronousQueue();
-            assertEquals(0, q.remainingCapacity());
-            q.add(new Integer(0));
-        } catch (IllegalStateException success){
-	}   
-    }
-
-    public void testAddAll1(){
-        try {
-            SynchronousQueue q = new SynchronousQueue();
-            q.addAll(null);
-            fail("Cannot add null collection");
-        }
-        catch (NullPointerException success) {}
-    }
-    public void testAddAll2(){
-        try {
-            SynchronousQueue q = new SynchronousQueue();
-            Integer[] ints = new Integer[N];
-            q.addAll(Arrays.asList(ints));
-            fail("Cannot add null elements");
-        }
-        catch (NullPointerException success) {}
-    }
-    public void testAddAll4(){
-        try {
-            SynchronousQueue q = new SynchronousQueue();
-            Integer[] ints = new Integer[N];
-            for (int i = 0; i < N; ++i)
-                ints[i] = new Integer(i);
-            q.addAll(Arrays.asList(ints));
-            fail("Cannot add with insufficient capacity");
-        }
-        catch (IllegalStateException success) {}
-    }
-
-    public void testPutNull() {
-	try {
-            SynchronousQueue q = new SynchronousQueue();
-            q.put(null);
-            fail("put should throw NPE");
-        } 
-        catch (NullPointerException success){
-	}   
-        catch (InterruptedException ie) {
-	    fail("Unexpected exception");
-        }
-     }
+public class SynchronousQueueTest extends JSR166TestCase {
 
-    public void testBlockingPut(){
-        Thread t = new Thread(new Runnable() {
-                public void run() {
-                    try {
-                        SynchronousQueue q = new SynchronousQueue();
-                        q.put(new Integer(0));
-                        fail("put should block");
-                    } catch (InterruptedException ie){
-                    }   
-                }});
-        t.start();
-        try { 
-           Thread.sleep(SHORT_DELAY_MS); 
-           t.interrupt();
-           t.join();
-        }
-        catch (InterruptedException ie) {
-	    fail("Unexpected exception");
+    public static class Fair extends BlockingQueueTest {
+        protected BlockingQueue emptyCollection() {
+            return new SynchronousQueue(true);
         }
     }
 
-    public void testPutWithTake() {
-        final SynchronousQueue q = new SynchronousQueue();
-        Thread t = new Thread(new Runnable() {
-                public void run(){
-                    int added = 0;
-                    try {
-                        q.put(new Object());
-                        ++added;
-                        q.put(new Object());
-                        ++added;
-                        q.put(new Object());
-                        ++added;
-                        q.put(new Object());
-                        ++added;
-			fail("Should block");
-                    } catch (InterruptedException e){
-                        assertTrue(added >= 1);
-                    }
-                }
-            });
-        try {
-            t.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            q.take();
-            Thread.sleep(SHORT_DELAY_MS);
-            t.interrupt();
-            t.join();
-        } catch (Exception e){
-            fail("Unexpected exception");
+    public static class NonFair extends BlockingQueueTest {
+        protected BlockingQueue emptyCollection() {
+            return new SynchronousQueue(false);
         }
     }
 
-    public void testTimedOffer() {
-        final SynchronousQueue q = new SynchronousQueue();
-        Thread t = new Thread(new Runnable() {
-                public void run(){
-                    try {
-
-                        assertFalse(q.offer(new Object(), SHORT_DELAY_MS/2, TimeUnit.MILLISECONDS));
-                        q.offer(new Object(), LONG_DELAY_MS, TimeUnit.MILLISECONDS);
-			fail("Should block");
-                    } catch (InterruptedException success){}
-                }
-            });
-        
-        try {
-            t.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            t.interrupt();
-            t.join();
-        } catch (Exception e){
-            fail("Unexpected exception");
-        }
+    public static void main(String[] args) {
+        main(suite(), args);
     }
 
-
-    public void testTakeFromEmpty() {
-        final SynchronousQueue q = new SynchronousQueue();
-        Thread t = new Thread(new Runnable() {
-                public void run(){
-                    try {
-                        q.take();
-			fail("Should block");
-                    } catch (InterruptedException success){ }                
-                }
-            });
-        try {
-            t.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            t.interrupt();
-            t.join();
-        } catch (Exception e){
-            fail("Unexpected exception");
-        }
+    public static Test suite() {
+        return newTestSuite(SynchronousQueueTest.class,
+                            new Fair().testSuite(),
+                            new NonFair().testSuite());
     }
 
-    public void testPoll(){
-        SynchronousQueue q = new SynchronousQueue();
-	assertNull(q.poll());
+    /**
+     * Any SynchronousQueue is both empty and full
+     */
+    public void testEmptyFull()      { testEmptyFull(false); }
+    public void testEmptyFull_fair() { testEmptyFull(true); }
+    public void testEmptyFull(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        assertTrue(q.isEmpty());
+        assertEquals(0, q.size());
+        assertEquals(0, q.remainingCapacity());
+        assertFalse(q.offer(zero));
     }
 
-    public void testTimedPoll0() {
+    /**
+     * offer fails if no active taker
+     */
+    public void testOffer()      { testOffer(false); }
+    public void testOffer_fair() { testOffer(true); }
+    public void testOffer(boolean fair) {
+        SynchronousQueue q = new SynchronousQueue(fair);
+        assertFalse(q.offer(one));
+    }
+
+    /**
+     * add throws IllegalStateException if no active taker
+     */
+    public void testAdd()      { testAdd(false); }
+    public void testAdd_fair() { testAdd(true); }
+    public void testAdd(boolean fair) {
+        SynchronousQueue q = new SynchronousQueue(fair);
+        assertEquals(0, q.remainingCapacity());
         try {
-            SynchronousQueue q = new SynchronousQueue();
-            assertNull(q.poll(0, TimeUnit.MILLISECONDS));
-        } catch (InterruptedException e){
-	    fail("Unexpected exception");
-	}   
-    }
+            q.add(one);
+            shouldThrow();
+        } catch (IllegalStateException success) {}
+    }
+
+    /**
+     * addAll(this) throws IllegalArgumentException
+     */
+    public void testAddAll_self()      { testAddAll_self(false); }
+    public void testAddAll_self_fair() { testAddAll_self(true); }
+    public void testAddAll_self(boolean fair) {
+        SynchronousQueue q = new SynchronousQueue(fair);
+        try {
+            q.addAll(q);
+            shouldThrow();
+        } catch (IllegalArgumentException success) {}
+    }
+
+    /**
+     * addAll throws ISE if no active taker
+     */
+    public void testAddAll_ISE()      { testAddAll_ISE(false); }
+    public void testAddAll_ISE_fair() { testAddAll_ISE(true); }
+    public void testAddAll_ISE(boolean fair) {
+        SynchronousQueue q = new SynchronousQueue(fair);
+        Integer[] ints = new Integer[1];
+        for (int i = 0; i < ints.length; i++)
+            ints[i] = i;
+        Collection<Integer> coll = Arrays.asList(ints);
+        try {
+            q.addAll(coll);
+            shouldThrow();
+        } catch (IllegalStateException success) {}
+    }
+
+    /**
+     * put blocks interruptibly if no active taker
+     */
+    public void testBlockingPut()      { testBlockingPut(false); }
+    public void testBlockingPut_fair() { testBlockingPut(true); }
+    public void testBlockingPut(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                Thread.currentThread().interrupt();
+                try {
+                    q.put(99);
+                    shouldThrow();
+                } catch (InterruptedException success) {}
+                assertFalse(Thread.interrupted());
 
-    public void testTimedPoll() {
-        try {
-            SynchronousQueue q = new SynchronousQueue();
-            assertNull(q.poll(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
-        } catch (InterruptedException e){
-	    fail("Unexpected exception");
-	}   
+                pleaseInterrupt.countDown();
+                try {
+                    q.put(99);
+                    shouldThrow();
+                } catch (InterruptedException success) {}
+                assertFalse(Thread.interrupted());
+            }});
+
+        await(pleaseInterrupt);
+        assertThreadStaysAlive(t);
+        t.interrupt();
+        awaitTermination(t);
+        assertEquals(0, q.remainingCapacity());
     }
 
-    public void testInterruptedTimedPoll(){
-        Thread t = new Thread(new Runnable() {
-                public void run() {
-                    try {
-                        SynchronousQueue q = new SynchronousQueue();
-                        assertNull(q.poll(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
-                    } catch (InterruptedException success){
-                    }   
-                }});
-        t.start();
-        try { 
-           Thread.sleep(SHORT_DELAY_MS); 
-           t.interrupt();
-           t.join();
-        }
-        catch (InterruptedException ie) {
-	    fail("Unexpected exception");
-        }
-    }
+    /**
+     * put blocks interruptibly waiting for take
+     */
+    public void testPutWithTake()      { testPutWithTake(false); }
+    public void testPutWithTake_fair() { testPutWithTake(true); }
+    public void testPutWithTake(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        final CountDownLatch pleaseTake = new CountDownLatch(1);
+        final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                pleaseTake.countDown();
+                q.put(one);
 
-    public void testTimedPollWithOffer(){
-        final SynchronousQueue q = new SynchronousQueue();
-        Thread t = new Thread(new Runnable() {
-                public void run(){
-                    try {
-                        assertNull(q.poll(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
-                        q.poll(LONG_DELAY_MS, TimeUnit.MILLISECONDS);
-                        q.poll(LONG_DELAY_MS, TimeUnit.MILLISECONDS);
-			fail("Should block");
-                    } catch (InterruptedException success) { }                
-                }
-            });
-        try {
-            t.start();
-            Thread.sleep(SHORT_DELAY_MS * 2);
-            assertTrue(q.offer(new Integer(0), SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
-            t.interrupt();
-            t.join();
-        } catch (Exception e){
-            fail("Unexpected exception");
-        }
-    }  
+                pleaseInterrupt.countDown();
+                try {
+                    q.put(99);
+                    shouldThrow();
+                } catch (InterruptedException success) {}
+                assertFalse(Thread.interrupted());
+            }});
 
+        await(pleaseTake);
+        assertEquals(0, q.remainingCapacity());
+        try { assertSame(one, q.take()); }
+        catch (InterruptedException e) { threadUnexpectedException(e); }
 
-    public void testPeek(){
-        SynchronousQueue q = new SynchronousQueue();
-	assertNull(q.peek());
+        await(pleaseInterrupt);
+        assertThreadStaysAlive(t);
+        t.interrupt();
+        awaitTermination(t);
+        assertEquals(0, q.remainingCapacity());
     }
 
-    public void testElement(){
-        SynchronousQueue q = new SynchronousQueue();
+    /**
+     * timed offer times out if elements not taken
+     */
+    public void testTimedOffer()      { testTimedOffer(false); }
+    public void testTimedOffer_fair() { testTimedOffer(true); }
+    public void testTimedOffer(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                long startTime = System.nanoTime();
+                assertFalse(q.offer(new Object(), timeoutMillis(), MILLISECONDS));
+                assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
+                pleaseInterrupt.countDown();
+                try {
+                    q.offer(new Object(), 2 * LONG_DELAY_MS, MILLISECONDS);
+                    shouldThrow();
+                } catch (InterruptedException success) {}
+            }});
+
+        await(pleaseInterrupt);
+        assertThreadStaysAlive(t);
+        t.interrupt();
+        awaitTermination(t);
+    }
+
+    /**
+     * poll return null if no active putter
+     */
+    public void testPoll()      { testPoll(false); }
+    public void testPoll_fair() { testPoll(true); }
+    public void testPoll(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        assertNull(q.poll());
+    }
+
+    /**
+     * timed poll with zero timeout times out if no active putter
+     */
+    public void testTimedPoll0()      { testTimedPoll0(false); }
+    public void testTimedPoll0_fair() { testTimedPoll0(true); }
+    public void testTimedPoll0(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        try { assertNull(q.poll(0, MILLISECONDS)); }
+        catch (InterruptedException e) { threadUnexpectedException(e); }
+    }
+
+    /**
+     * timed poll with nonzero timeout times out if no active putter
+     */
+    public void testTimedPoll()      { testTimedPoll(false); }
+    public void testTimedPoll_fair() { testTimedPoll(true); }
+    public void testTimedPoll(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        long startTime = System.nanoTime();
+        try { assertNull(q.poll(timeoutMillis(), MILLISECONDS)); }
+        catch (InterruptedException e) { threadUnexpectedException(e); }
+        assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
+    }
+
+    /**
+     * timed poll before a delayed offer times out, returning null;
+     * after offer succeeds; on interruption throws
+     */
+    public void testTimedPollWithOffer()      { testTimedPollWithOffer(false); }
+    public void testTimedPollWithOffer_fair() { testTimedPollWithOffer(true); }
+    public void testTimedPollWithOffer(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        final CountDownLatch pleaseOffer = new CountDownLatch(1);
+        final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                long startTime = System.nanoTime();
+                assertNull(q.poll(timeoutMillis(), MILLISECONDS));
+                assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
+
+                pleaseOffer.countDown();
+                startTime = System.nanoTime();
+                assertSame(zero, q.poll(LONG_DELAY_MS, MILLISECONDS));
+                assertTrue(millisElapsedSince(startTime) < MEDIUM_DELAY_MS);
+
+                Thread.currentThread().interrupt();
+                try {
+                    q.poll(LONG_DELAY_MS, MILLISECONDS);
+                    shouldThrow();
+                } catch (InterruptedException success) {}
+                assertFalse(Thread.interrupted());
+
+                pleaseInterrupt.countDown();
+                try {
+                    q.poll(LONG_DELAY_MS, MILLISECONDS);
+                    shouldThrow();
+                } catch (InterruptedException success) {}
+                assertFalse(Thread.interrupted());
+            }});
+
+        await(pleaseOffer);
+        long startTime = System.nanoTime();
+        try { assertTrue(q.offer(zero, LONG_DELAY_MS, MILLISECONDS)); }
+        catch (InterruptedException e) { threadUnexpectedException(e); }
+        assertTrue(millisElapsedSince(startTime) < MEDIUM_DELAY_MS);
+
+        await(pleaseInterrupt);
+        assertThreadStaysAlive(t);
+        t.interrupt();
+        awaitTermination(t);
+    }
+
+    /**
+     * peek() returns null if no active putter
+     */
+    public void testPeek()      { testPeek(false); }
+    public void testPeek_fair() { testPeek(true); }
+    public void testPeek(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        assertNull(q.peek());
+    }
+
+    /**
+     * element() throws NoSuchElementException if no active putter
+     */
+    public void testElement()      { testElement(false); }
+    public void testElement_fair() { testElement(true); }
+    public void testElement(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
         try {
             q.element();
-            fail("no such element");
-        }
-        catch (NoSuchElementException success) {}
+            shouldThrow();
+        } catch (NoSuchElementException success) {}
     }
 
-    public void testRemove(){
-        SynchronousQueue q = new SynchronousQueue();
+    /**
+     * remove() throws NoSuchElementException if no active putter
+     */
+    public void testRemove()      { testRemove(false); }
+    public void testRemove_fair() { testRemove(true); }
+    public void testRemove(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
         try {
             q.remove();
-            fail("remove should throw");
-        } catch (NoSuchElementException success){
-	}   
+            shouldThrow();
+        } catch (NoSuchElementException success) {}
     }
 
-    public void testRemoveElement(){
-        SynchronousQueue q = new SynchronousQueue();
-        for (int i = 1; i < N; i+=2) {
-            assertFalse(q.remove(new Integer(i)));
-        }
-        assertTrue(q.isEmpty());
-    }
-	
-    public void testContains(){
-        SynchronousQueue q = new SynchronousQueue();
-        for (int i = 0; i < N; ++i) {
-            assertFalse(q.contains(new Integer(i)));
-        }
-    }
-
-    public void testClear(){
-        SynchronousQueue q = new SynchronousQueue();
+    /**
+     * contains returns false
+     */
+    public void testContains()      { testContains(false); }
+    public void testContains_fair() { testContains(true); }
+    public void testContains(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        assertFalse(q.contains(zero));
+    }
+
+    /**
+     * clear ensures isEmpty
+     */
+    public void testClear()      { testClear(false); }
+    public void testClear_fair() { testClear(true); }
+    public void testClear(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
         q.clear();
         assertTrue(q.isEmpty());
     }
 
-    public void testContainsAll(){
-        SynchronousQueue q = new SynchronousQueue();
+    /**
+     * containsAll returns false unless empty
+     */
+    public void testContainsAll()      { testContainsAll(false); }
+    public void testContainsAll_fair() { testContainsAll(true); }
+    public void testContainsAll(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
         Integer[] empty = new Integer[0];
-        Integer[] ints = new Integer[1]; ints[0] = new Integer(0);
-        //        assertTrue(q.containsAll(Arrays.asList(empty)));
+        assertTrue(q.containsAll(Arrays.asList(empty)));
+        Integer[] ints = new Integer[1]; ints[0] = zero;
         assertFalse(q.containsAll(Arrays.asList(ints)));
     }
 
-    public void testRetainAll(){
-        SynchronousQueue q = new SynchronousQueue();
+    /**
+     * retainAll returns false
+     */
+    public void testRetainAll()      { testRetainAll(false); }
+    public void testRetainAll_fair() { testRetainAll(true); }
+    public void testRetainAll(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
         Integer[] empty = new Integer[0];
-        Integer[] ints = new Integer[1]; ints[0] = new Integer(0);
-        q.retainAll(Arrays.asList(ints));
-        //        assertTrue(q.containsAll(Arrays.asList(empty)));
-        assertFalse(q.containsAll(Arrays.asList(ints)));
+        assertFalse(q.retainAll(Arrays.asList(empty)));
+        Integer[] ints = new Integer[1]; ints[0] = zero;
+        assertFalse(q.retainAll(Arrays.asList(ints)));
     }
 
-    public void testRemoveAll(){
-        SynchronousQueue q = new SynchronousQueue();
+    /**
+     * removeAll returns false
+     */
+    public void testRemoveAll()      { testRemoveAll(false); }
+    public void testRemoveAll_fair() { testRemoveAll(true); }
+    public void testRemoveAll(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
         Integer[] empty = new Integer[0];
-        Integer[] ints = new Integer[1]; ints[0] = new Integer(0);
-        q.removeAll(Arrays.asList(ints));
-        //        assertTrue(q.containsAll(Arrays.asList(empty)));
+        assertFalse(q.removeAll(Arrays.asList(empty)));
+        Integer[] ints = new Integer[1]; ints[0] = zero;
         assertFalse(q.containsAll(Arrays.asList(ints)));
     }
 
-
-    public void testToArray(){
-        SynchronousQueue q = new SynchronousQueue();
-	Object[] o = q.toArray();
-        assertEquals(o.length, 0);
-    }
-
-    public void testToArray2(){
-        SynchronousQueue q = new SynchronousQueue();
-	Integer[] ints = new Integer[1];
-        assertNull(ints[0]);
-    }
-    
-    public void testIterator(){
-        SynchronousQueue q = new SynchronousQueue();
-	Iterator it = q.iterator();
-        assertFalse(it.hasNext());
-        try {
-            Object x = it.next();
-            fail("should throw");
-        }
-        catch (NoSuchElementException success) {}
-    }
-
-    public void testIteratorRemove(){
-        SynchronousQueue q = new SynchronousQueue();
-	Iterator it = q.iterator();
+    /**
+     * toArray is empty
+     */
+    public void testToArray()      { testToArray(false); }
+    public void testToArray_fair() { testToArray(true); }
+    public void testToArray(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        Object[] o = q.toArray();
+        assertEquals(0, o.length);
+    }
+
+    /**
+     * toArray(Integer array) returns its argument with the first
+     * element (if present) nulled out
+     */
+    public void testToArray2()      { testToArray2(false); }
+    public void testToArray2_fair() { testToArray2(true); }
+    public void testToArray2(boolean fair) {
+        final SynchronousQueue<Integer> q
+            = new SynchronousQueue<Integer>(fair);
+        Integer[] a;
+
+        a = new Integer[0];
+        assertSame(a, q.toArray(a));
+
+        a = new Integer[3];
+        Arrays.fill(a, 42);
+        assertSame(a, q.toArray(a));
+        assertNull(a[0]);
+        for (int i = 1; i < a.length; i++)
+            assertEquals(42, (int) a[i]);
+    }
+
+    /**
+     * toArray(null) throws NPE
+     */
+    public void testToArray_null()      { testToArray_null(false); }
+    public void testToArray_null_fair() { testToArray_null(true); }
+    public void testToArray_null(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        try {
+            Object[] o = q.toArray(null);
+            shouldThrow();
+        } catch (NullPointerException success) {}
+    }
+
+    /**
+     * iterator does not traverse any elements
+     */
+    public void testIterator()      { testIterator(false); }
+    public void testIterator_fair() { testIterator(true); }
+    public void testIterator(boolean fair) {
+        assertIteratorExhausted(new SynchronousQueue(fair).iterator());
+    }
+
+    /**
+     * iterator remove throws ISE
+     */
+    public void testIteratorRemove()      { testIteratorRemove(false); }
+    public void testIteratorRemove_fair() { testIteratorRemove(true); }
+    public void testIteratorRemove(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        Iterator it = q.iterator();
         try {
             it.remove();
-            fail("should throw");
-        }
-        catch (IllegalStateException success) {}
+            shouldThrow();
+        } catch (IllegalStateException success) {}
     }
 
-    public void testToString(){
-        SynchronousQueue q = new SynchronousQueue();
+    /**
+     * toString returns a non-null string
+     */
+    public void testToString()      { testToString(false); }
+    public void testToString_fair() { testToString(true); }
+    public void testToString(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
         String s = q.toString();
-        assertTrue(s != null);
-    }        
-
-
-    public void testOfferInExecutor() {
-        final SynchronousQueue q = new SynchronousQueue();
-        ExecutorService executor = Executors.newFixedThreadPool(2);
-        final Integer one = new Integer(1);
+        assertNotNull(s);
+    }
 
-        executor.execute(new Runnable() {
-            public void run() {
-                assertFalse(q.offer(one));
-                try {
-                    assertTrue(q.offer(one, MEDIUM_DELAY_MS * 2, TimeUnit.MILLISECONDS));
+    /**
+     * offer transfers elements across Executor tasks
+     */
+    public void testOfferInExecutor()      { testOfferInExecutor(false); }
+    public void testOfferInExecutor_fair() { testOfferInExecutor(true); }
+    public void testOfferInExecutor(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        final CheckedBarrier threadsStarted = new CheckedBarrier(2);
+        final ExecutorService executor = Executors.newFixedThreadPool(2);
+        try (PoolCleaner cleaner = cleaner(executor)) {
+
+            executor.execute(new CheckedRunnable() {
+                public void realRun() throws InterruptedException {
+                    assertFalse(q.offer(one));
+                    threadsStarted.await();
+                    assertTrue(q.offer(one, LONG_DELAY_MS, MILLISECONDS));
                     assertEquals(0, q.remainingCapacity());
-                }
-                catch (InterruptedException e) {
-                    fail("should not be interrupted");
-                }
-            }
-        });
-
-        executor.execute(new Runnable() {
-            public void run() {
-                try {
-                    Thread.sleep(MEDIUM_DELAY_MS);
-                    assertEquals(one, q.take());
-                }
-                catch (InterruptedException e) {
-                    fail("should not be interrupted");
-                }
-            }
-        });
-        
-        executor.shutdown();
+                }});
 
+            executor.execute(new CheckedRunnable() {
+                public void realRun() throws InterruptedException {
+                    threadsStarted.await();
+                    assertSame(one, q.take());
+                }});
+        }
     }
 
-    public void testPollInExecutor() {
-
-        final SynchronousQueue q = new SynchronousQueue();
-
-        ExecutorService executor = Executors.newFixedThreadPool(2);
-
-        executor.execute(new Runnable() {
-            public void run() {
-                assertNull(q.poll());
-                try {
-                    assertTrue(null != q.poll(MEDIUM_DELAY_MS * 2, TimeUnit.MILLISECONDS));
+    /**
+     * timed poll retrieves elements across Executor threads
+     */
+    public void testPollInExecutor()      { testPollInExecutor(false); }
+    public void testPollInExecutor_fair() { testPollInExecutor(true); }
+    public void testPollInExecutor(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        final CheckedBarrier threadsStarted = new CheckedBarrier(2);
+        final ExecutorService executor = Executors.newFixedThreadPool(2);
+        try (PoolCleaner cleaner = cleaner(executor)) {
+            executor.execute(new CheckedRunnable() {
+                public void realRun() throws InterruptedException {
+                    assertNull(q.poll());
+                    threadsStarted.await();
+                    assertSame(one, q.poll(LONG_DELAY_MS, MILLISECONDS));
                     assertTrue(q.isEmpty());
-                }
-                catch (InterruptedException e) {
-                    fail("should not be interrupted");
-                }
-            }
-        });
-
-        executor.execute(new Runnable() {
-            public void run() {
-                try {
-                    Thread.sleep(MEDIUM_DELAY_MS);
-                    q.put(new Integer(1));
-                }
-                catch (InterruptedException e) {
-                    fail("should not be interrupted");
-                }
-            }
-        });
-        
-        executor.shutdown();
+                }});
 
+            executor.execute(new CheckedRunnable() {
+                public void realRun() throws InterruptedException {
+                    threadsStarted.await();
+                    q.put(one);
+                }});
+        }
     }
 
+    /**
+     * a deserialized serialized queue is usable
+     */
     public void testSerialization() {
-        SynchronousQueue q = new SynchronousQueue();
-        try {
-            ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
-            ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
-            out.writeObject(q);
-            out.close();
-
-            ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
-            ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
-            SynchronousQueue r = (SynchronousQueue)in.readObject();
-            assertEquals(q.size(), r.size());
-            while (!q.isEmpty()) 
-                assertEquals(q.remove(), r.remove());
-        } catch(Exception e){
-            fail("unexpected exception");
+        final SynchronousQueue x = new SynchronousQueue();
+        final SynchronousQueue y = new SynchronousQueue(false);
+        final SynchronousQueue z = new SynchronousQueue(true);
+        assertSerialEquals(x, y);
+        assertNotSerialEquals(x, z);
+        SynchronousQueue[] qs = { x, y, z };
+        for (SynchronousQueue q : qs) {
+            SynchronousQueue clone = serialClone(q);
+            assertNotSame(q, clone);
+            assertSerialEquals(q, clone);
+            assertTrue(clone.isEmpty());
+            assertEquals(0, clone.size());
+            assertEquals(0, clone.remainingCapacity());
+            assertFalse(clone.offer(zero));
         }
     }
 
+    /**
+     * drainTo(c) of empty queue doesn't transfer elements
+     */
+    public void testDrainTo()      { testDrainTo(false); }
+    public void testDrainTo_fair() { testDrainTo(true); }
+    public void testDrainTo(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        ArrayList l = new ArrayList();
+        q.drainTo(l);
+        assertEquals(0, q.size());
+        assertEquals(0, l.size());
+    }
+
+    /**
+     * drainTo empties queue, unblocking a waiting put.
+     */
+    public void testDrainToWithActivePut()      { testDrainToWithActivePut(false); }
+    public void testDrainToWithActivePut_fair() { testDrainToWithActivePut(true); }
+    public void testDrainToWithActivePut(boolean fair) {
+        final SynchronousQueue q = new SynchronousQueue(fair);
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                q.put(one);
+            }});
+
+        ArrayList l = new ArrayList();
+        long startTime = System.nanoTime();
+        while (l.isEmpty()) {
+            q.drainTo(l);
+            if (millisElapsedSince(startTime) > LONG_DELAY_MS)
+                fail("timed out");
+            Thread.yield();
+        }
+        assertTrue(l.size() == 1);
+        assertSame(one, l.get(0));
+        awaitTermination(t);
+    }
+
+    /**
+     * drainTo(c, n) empties up to n elements of queue into c
+     */
+    public void testDrainToN() throws InterruptedException {
+        final SynchronousQueue q = new SynchronousQueue();
+        Thread t1 = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                q.put(one);
+            }});
+
+        Thread t2 = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                q.put(two);
+            }});
+
+        ArrayList l = new ArrayList();
+        int drained;
+        while ((drained = q.drainTo(l, 1)) == 0) Thread.yield();
+        assertEquals(1, drained);
+        assertEquals(1, l.size());
+        while ((drained = q.drainTo(l, 1)) == 0) Thread.yield();
+        assertEquals(1, drained);
+        assertEquals(2, l.size());
+        assertTrue(l.contains(one));
+        assertTrue(l.contains(two));
+        awaitTermination(t1);
+        awaitTermination(t2);
+    }
+
+    /**
+     * remove(null), contains(null) always return false
+     */
+    public void testNeverContainsNull() {
+        Collection<?> q = new SynchronousQueue();
+        assertFalse(q.contains(null));
+        assertFalse(q.remove(null));
+    }
+
 }