--- jsr166/src/test/tck/SynchronousQueueTest.java	2003/08/31 19:24:55	1.1
+++ jsr166/src/test/tck/SynchronousQueueTest.java	2010/11/18 20:18:43	1.29
@@ -1,443 +1,728 @@
 /*
- * 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/licenses/publicdomain
+ * Other contributors include Andrew Wright, Jeffrey Hayes,
+ * Pat Fisher, Mike Judd.
  */
 
 import junit.framework.*;
 import java.util.*;
 import java.util.concurrent.*;
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import java.io.*;
 
-public class SynchronousQueueTest extends TestCase {
+public class SynchronousQueueTest extends JSR166TestCase {
 
-    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; 
+    public static class Fair extends BlockingQueueTest {
+        protected BlockingQueue emptyCollection() {
+            return new SynchronousQueue(true);
+        }
+    }
+
+    public static class NonFair extends BlockingQueueTest {
+        protected BlockingQueue emptyCollection() {
+            return new SynchronousQueue(false);
+        }
+    }
 
     public static void main(String[] args) {
-	junit.textui.TestRunner.run (suite());	
+        junit.textui.TestRunner.run(suite());
     }
 
     public static Test suite() {
-	return new TestSuite(SynchronousQueueTest.class);
+        return newTestSuite(SynchronousQueueTest.class,
+                            new Fair().testSuite(),
+                            new NonFair().testSuite());
     }
 
-    public void testEmptyFull() {
-        SynchronousQueue q = new SynchronousQueue();
+    /**
+     * Any SynchronousQueue is both empty and full
+     */
+    public void testEmptyFull(SynchronousQueue q) {
         assertTrue(q.isEmpty());
-	assertEquals(0, q.size());
+        assertEquals(0, q.size());
         assertEquals(0, q.remainingCapacity());
-        assertFalse(q.offer(new Integer(3)));
+        assertFalse(q.offer(zero));
     }
 
-    public void testOfferNull(){
-	try {
+    /**
+     * A non-fair SynchronousQueue is both empty and full
+     */
+    public void testEmptyFull() {
+        testEmptyFull(new SynchronousQueue());
+    }
+
+    /**
+     * A fair SynchronousQueue is both empty and full
+     */
+    public void testFairEmptyFull() {
+        testEmptyFull(new SynchronousQueue(true));
+    }
+
+    /**
+     * offer(null) throws NPE
+     */
+    public void testOfferNull() {
+        try {
             SynchronousQueue q = new SynchronousQueue();
             q.offer(null);
-            fail("should throw NPE");
-        } catch (NullPointerException success) { }   
+            shouldThrow();
+        } catch (NullPointerException success) {}
+    }
+
+    /**
+     * add(null) throws NPE
+     */
+    public void testAddNull() {
+        try {
+            SynchronousQueue q = new SynchronousQueue();
+            q.add(null);
+            shouldThrow();
+        } catch (NullPointerException success) {}
     }
 
-    public void testOffer(){
+    /**
+     * offer fails if no active taker
+     */
+    public void testOffer() {
         SynchronousQueue q = new SynchronousQueue();
-        assertFalse(q.offer(new Integer(1)));
+        assertFalse(q.offer(one));
     }
 
-    public void testAdd(){
-	try {
+    /**
+     * add throws ISE if no active taker
+     */
+    public void testAdd() {
+        try {
             SynchronousQueue q = new SynchronousQueue();
             assertEquals(0, q.remainingCapacity());
-            q.add(new Integer(0));
-        } catch (IllegalStateException success){
-	}   
+            q.add(one);
+            shouldThrow();
+        } catch (IllegalStateException success) {}
     }
 
-    public void testAddAll1(){
+    /**
+     * addAll(null) throws NPE
+     */
+    public void testAddAll1() {
         try {
             SynchronousQueue q = new SynchronousQueue();
             q.addAll(null);
-            fail("Cannot add null collection");
-        }
-        catch (NullPointerException success) {}
+            shouldThrow();
+        } catch (NullPointerException success) {}
     }
-    public void testAddAll2(){
+
+    /**
+     * addAll(this) throws IAE
+     */
+    public void testAddAllSelf() {
         try {
             SynchronousQueue q = new SynchronousQueue();
-            Integer[] ints = new Integer[N];
+            q.addAll(q);
+            shouldThrow();
+        } catch (IllegalArgumentException success) {}
+    }
+
+    /**
+     * addAll of a collection with null elements throws NPE
+     */
+    public void testAddAll2() {
+        try {
+            SynchronousQueue q = new SynchronousQueue();
+            Integer[] ints = new Integer[1];
             q.addAll(Arrays.asList(ints));
-            fail("Cannot add null elements");
-        }
-        catch (NullPointerException success) {}
+            shouldThrow();
+        } catch (NullPointerException success) {}
     }
-    public void testAddAll4(){
+
+    /**
+     * addAll throws ISE if no active taker
+     */
+    public void testAddAll4() {
         try {
             SynchronousQueue q = new SynchronousQueue();
-            Integer[] ints = new Integer[N];
-            for (int i = 0; i < N; ++i)
+            Integer[] ints = new Integer[1];
+            for (int i = 0; i < 1; ++i)
                 ints[i] = new Integer(i);
             q.addAll(Arrays.asList(ints));
-            fail("Cannot add with insufficient capacity");
-        }
-        catch (IllegalStateException success) {}
+            shouldThrow();
+        } catch (IllegalStateException success) {}
     }
 
-    public void testPutNull() {
-	try {
+    /**
+     * put(null) throws NPE
+     */
+    public void testPutNull() throws InterruptedException {
+        try {
             SynchronousQueue q = new SynchronousQueue();
             q.put(null);
-            fail("put should throw NPE");
-        } 
-        catch (NullPointerException success){
-	}   
-        catch (InterruptedException ie) {
-	    fail("Unexpected exception");
-        }
+            shouldThrow();
+        } catch (NullPointerException success) {}
      }
 
-    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){
-                    }   
-                }});
+    /**
+     * put blocks interruptibly if no active taker
+     */
+    public void testBlockingPut() throws InterruptedException {
+        Thread t = new Thread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                SynchronousQueue q = new SynchronousQueue();
+                q.put(zero);
+            }});
+
         t.start();
-        try { 
-           Thread.sleep(SHORT_DELAY_MS); 
-           t.interrupt();
-           t.join();
-        }
-        catch (InterruptedException ie) {
-	    fail("Unexpected exception");
-        }
+        Thread.sleep(SHORT_DELAY_MS);
+        t.interrupt();
+        t.join();
     }
 
-    public void testPutWithTake() {
+    /**
+     * put blocks waiting for take
+     */
+    public void testPutWithTake() throws InterruptedException {
         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());
+        Thread t = new Thread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                int added = 0;
+                try {
+                    while (true) {
+                        q.put(added);
                         ++added;
-			fail("Should block");
-                    } catch (InterruptedException e){
-                        assertTrue(added >= 1);
                     }
+                } catch (InterruptedException success) {
+                    assertEquals(1, added);
                 }
-            });
-        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");
-        }
+            }});
+
+        t.start();
+        Thread.sleep(SHORT_DELAY_MS);
+        assertEquals(0, q.take());
+        Thread.sleep(SHORT_DELAY_MS);
+        t.interrupt();
+        t.join();
+    }
+
+    /**
+     * timed offer times out if elements not taken
+     */
+    public void testTimedOffer(final SynchronousQueue q)
+            throws InterruptedException {
+        final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                long t0 = System.nanoTime();
+                assertFalse(q.offer(new Object(), SHORT_DELAY_MS, MILLISECONDS));
+                assertTrue(millisElapsedSince(t0) >= SHORT_DELAY_MS);
+                pleaseInterrupt.countDown();
+                t0 = System.nanoTime();
+                try {
+                    q.offer(new Object(), LONG_DELAY_MS, MILLISECONDS);
+                    shouldThrow();
+                } catch (InterruptedException success) {}
+                assertTrue(millisElapsedSince(t0) < MEDIUM_DELAY_MS);
+            }});
+
+        assertTrue(pleaseInterrupt.await(MEDIUM_DELAY_MS, MILLISECONDS));
+        t.interrupt();
+        awaitTermination(t, MEDIUM_DELAY_MS);
+    }
+
+    /**
+     * timed offer times out if elements not taken
+     */
+    public void testTimedOffer() throws InterruptedException {
+        testTimedOffer(new SynchronousQueue());
+    }
+
+    /**
+     * timed offer times out if elements not taken
+     */
+    public void testFairTimedOffer() throws InterruptedException {
+        testTimedOffer(new SynchronousQueue(true));
+    }
+
+    /**
+     * put blocks interruptibly if no active taker
+     */
+    public void testFairBlockingPut() throws InterruptedException {
+        Thread t = new Thread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                SynchronousQueue q = new SynchronousQueue(true);
+                q.put(zero);
+            }});
+
+        t.start();
+        Thread.sleep(SHORT_DELAY_MS);
+        t.interrupt();
+        t.join();
     }
 
-    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){}
+    /**
+     * put blocks waiting for take
+     */
+    public void testFairPutWithTake() throws InterruptedException {
+        final SynchronousQueue q = new SynchronousQueue(true);
+        Thread t = new Thread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                int added = 0;
+                try {
+                    while (true) {
+                        q.put(added);
+                        ++added;
+                    }
+                } catch (InterruptedException success) {
+                    assertEquals(1, added);
                 }
-            });
-        
-        try {
-            t.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            t.interrupt();
-            t.join();
-        } catch (Exception e){
-            fail("Unexpected exception");
-        }
-    }
+            }});
 
+        t.start();
+        Thread.sleep(SHORT_DELAY_MS);
+        assertEquals(0, q.take());
+        Thread.sleep(SHORT_DELAY_MS);
+        t.interrupt();
+        t.join();
+    }
+
+    /**
+     * take blocks interruptibly when empty
+     */
+    public void testFairTakeFromEmpty() throws InterruptedException {
+        final SynchronousQueue q = new SynchronousQueue(true);
+        Thread t = new Thread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                q.take();
+            }});
 
-    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");
-        }
+        t.start();
+        Thread.sleep(SHORT_DELAY_MS);
+        t.interrupt();
+        t.join();
     }
 
-    public void testPoll(){
+    /**
+     * poll return null if no active putter
+     */
+    public void testPoll() {
         SynchronousQueue q = new SynchronousQueue();
-	assertNull(q.poll());
+        assertNull(q.poll());
     }
 
-    public void testTimedPoll0() {
-        try {
-            SynchronousQueue q = new SynchronousQueue();
-            assertNull(q.poll(0, TimeUnit.MILLISECONDS));
-        } catch (InterruptedException e){
-	    fail("Unexpected exception");
-	}   
-    }
-
-    public void testTimedPoll() {
-        try {
-            SynchronousQueue q = new SynchronousQueue();
-            assertNull(q.poll(SHORT_DELAY_MS, TimeUnit.MILLISECONDS));
-        } catch (InterruptedException e){
-	    fail("Unexpected exception");
-	}   
+    /**
+     * timed poll with zero timeout times out if no active putter
+     */
+    public void testTimedPoll0() throws InterruptedException {
+        SynchronousQueue q = new SynchronousQueue();
+        assertNull(q.poll(0, MILLISECONDS));
     }
 
-    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");
-        }
+    /**
+     * timed poll with nonzero timeout times out if no active putter
+     */
+    public void testTimedPoll() throws InterruptedException {
+        SynchronousQueue q = new SynchronousQueue();
+        long t0 = System.nanoTime();
+        assertNull(q.poll(SHORT_DELAY_MS, MILLISECONDS));
+        assertTrue(millisElapsedSince(t0) >= SHORT_DELAY_MS);
     }
 
-    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");
-        }
-    }  
+    /**
+     * Interrupted timed poll throws InterruptedException instead of
+     * returning timeout status
+     */
+    public void testInterruptedTimedPoll(final SynchronousQueue q)
+            throws InterruptedException {
+        final CountDownLatch threadStarted = new CountDownLatch(1);
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                long t0 = System.nanoTime();
+                threadStarted.countDown();
+                try {
+                    q.poll(LONG_DELAY_MS, MILLISECONDS);
+                    shouldThrow();
+                } catch (InterruptedException success) {}
+                assertTrue(millisElapsedSince(t0) >= SHORT_DELAY_MS);
+                assertTrue(millisElapsedSince(t0) < MEDIUM_DELAY_MS);
+            }});
+
+        threadStarted.await();
+        Thread.sleep(SHORT_DELAY_MS);
+        t.interrupt();
+        awaitTermination(t, MEDIUM_DELAY_MS);
+    }
+
+    /**
+     * Interrupted timed poll throws InterruptedException instead of
+     * returning timeout status
+     */
+    public void testInterruptedTimedPoll() throws InterruptedException {
+        testInterruptedTimedPoll(new SynchronousQueue());
+    }
+
+    /**
+     * Interrupted timed poll throws InterruptedException instead of
+     * returning timeout status
+     */
+    public void testFairInterruptedTimedPoll() throws InterruptedException {
+        testInterruptedTimedPoll(new SynchronousQueue(true));
+    }
+
+    /**
+     * timed poll before a delayed offer times out, returning null;
+     * after offer succeeds; on interruption throws
+     */
+    public void testFairTimedPollWithOffer() throws InterruptedException {
+        final SynchronousQueue q = new SynchronousQueue(true);
+        final CountDownLatch pleaseOffer = new CountDownLatch(1);
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                long t0 = System.nanoTime();
+                assertNull(q.poll(SHORT_DELAY_MS, MILLISECONDS));
+                assertTrue(millisElapsedSince(t0) >= SHORT_DELAY_MS);
+
+                pleaseOffer.countDown();
+                t0 = System.nanoTime();
+                assertSame(zero, q.poll(LONG_DELAY_MS, MILLISECONDS));
+                assertTrue(millisElapsedSince(t0) < MEDIUM_DELAY_MS);
 
+                t0 = System.nanoTime();
+                try {
+                    q.poll(LONG_DELAY_MS, MILLISECONDS);
+                    shouldThrow();
+                } catch (InterruptedException success) {}
+                assertTrue(millisElapsedSince(t0) < MEDIUM_DELAY_MS);
+            }});
+
+        assertTrue(pleaseOffer.await(MEDIUM_DELAY_MS, MILLISECONDS));
+        long t0 = System.nanoTime();
+        assertTrue(q.offer(zero, LONG_DELAY_MS, MILLISECONDS));
+        assertTrue(millisElapsedSince(t0) < MEDIUM_DELAY_MS);
+        
+        t.interrupt();
+        awaitTermination(t, MEDIUM_DELAY_MS);
+    }
 
-    public void testPeek(){
+    /**
+     * peek() returns null if no active putter
+     */
+    public void testPeek() {
         SynchronousQueue q = new SynchronousQueue();
-	assertNull(q.peek());
+        assertNull(q.peek());
     }
 
-    public void testElement(){
+    /**
+     * element() throws NSEE if no active putter
+     */
+    public void testElement() {
         SynchronousQueue q = new SynchronousQueue();
         try {
             q.element();
-            fail("no such element");
-        }
-        catch (NoSuchElementException success) {}
+            shouldThrow();
+        } catch (NoSuchElementException success) {}
     }
 
-    public void testRemove(){
+    /**
+     * remove() throws NSEE if no active putter
+     */
+    public void testRemove() {
         SynchronousQueue q = new SynchronousQueue();
         try {
             q.remove();
-            fail("remove should throw");
-        } catch (NoSuchElementException success){
-	}   
+            shouldThrow();
+        } catch (NoSuchElementException success) {}
     }
 
-    public void testRemoveElement(){
+    /**
+     * remove(x) returns false
+     */
+    public void testRemoveElement() {
         SynchronousQueue q = new SynchronousQueue();
-        for (int i = 1; i < N; i+=2) {
-            assertFalse(q.remove(new Integer(i)));
-        }
-        assert(q.isEmpty());
+        assertFalse(q.remove(zero));
+        assertTrue(q.isEmpty());
     }
-	
-    public void testContains(){
-        SynchronousQueue q = new SynchronousQueue();
-        for (int i = 0; i < N; ++i) {
-            assertFalse(q.contains(new Integer(i)));
-        }
+
+    /**
+     * contains returns false
+     */
+    public void testContains() {
+        SynchronousQueue q = new SynchronousQueue();
+        assertFalse(q.contains(zero));
     }
 
-    public void testClear(){
+    /**
+     * clear ensures isEmpty
+     */
+    public void testClear() {
         SynchronousQueue q = new SynchronousQueue();
         q.clear();
         assertTrue(q.isEmpty());
     }
 
-    public void testContainsAll(){
+    /**
+     * containsAll returns false unless empty
+     */
+    public void testContainsAll() {
         SynchronousQueue q = new SynchronousQueue();
         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(){
+    /**
+     * retainAll returns false
+     */
+    public void testRetainAll() {
         SynchronousQueue q = new SynchronousQueue();
         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(){
+    /**
+     * removeAll returns false
+     */
+    public void testRemoveAll() {
         SynchronousQueue q = new SynchronousQueue();
         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(){
+    /**
+     * toArray is empty
+     */
+    public void testToArray() {
         SynchronousQueue q = new SynchronousQueue();
-	Object[] o = q.toArray();
+        Object[] o = q.toArray();
         assertEquals(o.length, 0);
     }
 
-    public void testToArray2(){
+    /**
+     * toArray(a) is nulled at position 0
+     */
+    public void testToArray2() {
         SynchronousQueue q = new SynchronousQueue();
-	Integer[] ints = new Integer[1];
+        Integer[] ints = new Integer[1];
         assertNull(ints[0]);
     }
-    
-    public void testIterator(){
+
+    /**
+     * toArray(null) throws NPE
+     */
+    public void testToArray_BadArg() {
+        SynchronousQueue q = new SynchronousQueue();
+        try {
+            Object o[] = q.toArray(null);
+            shouldThrow();
+        } catch (NullPointerException success) {}
+    }
+
+
+    /**
+     * iterator does not traverse any elements
+     */
+    public void testIterator() {
         SynchronousQueue q = new SynchronousQueue();
-	Iterator it = q.iterator();
+        Iterator it = q.iterator();
         assertFalse(it.hasNext());
         try {
             Object x = it.next();
-            fail("should throw");
-        }
-        catch (NoSuchElementException success) {}
+            shouldThrow();
+        } catch (NoSuchElementException success) {}
     }
 
-    public void testIteratorRemove(){
+    /**
+     * iterator remove throws ISE
+     */
+    public void testIteratorRemove() {
         SynchronousQueue q = new SynchronousQueue();
-	Iterator it = q.iterator();
+        Iterator it = q.iterator();
         try {
             it.remove();
-            fail("should throw");
-        }
-        catch (IllegalStateException success) {}
+            shouldThrow();
+        } catch (IllegalStateException success) {}
     }
 
-    public void testToString(){
+    /**
+     * toString returns a non-null string
+     */
+    public void testToString() {
         SynchronousQueue q = new SynchronousQueue();
         String s = q.toString();
-        assertTrue(s != null);
-    }        
+        assertNotNull(s);
+    }
 
 
+    /**
+     * offer transfers elements across Executor tasks
+     */
     public void testOfferInExecutor() {
         final SynchronousQueue q = new SynchronousQueue();
         ExecutorService executor = Executors.newFixedThreadPool(2);
-        final Integer one = new Integer(1);
 
-        executor.execute(new Runnable() {
-            public void run() {
+        executor.execute(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
                 assertFalse(q.offer(one));
-                try {
-                    assertTrue(q.offer(one, MEDIUM_DELAY_MS * 2, TimeUnit.MILLISECONDS));
-                    assertEquals(0, q.remainingCapacity());
-                }
-                catch (InterruptedException e) {
-                    fail("should not be interrupted");
-                }
-            }
-        });
+                assertTrue(q.offer(one, MEDIUM_DELAY_MS, MILLISECONDS));
+                assertEquals(0, q.remainingCapacity());
+            }});
+
+        executor.execute(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                Thread.sleep(SMALL_DELAY_MS);
+                assertSame(one, q.take());
+            }});
+
+        joinPool(executor);
+    }
+
+    /**
+     * poll retrieves elements across Executor threads
+     */
+    public void testPollInExecutor() {
+        final SynchronousQueue q = new SynchronousQueue();
+        ExecutorService executor = Executors.newFixedThreadPool(2);
+        executor.execute(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                assertNull(q.poll());
+                assertSame(one, q.poll(MEDIUM_DELAY_MS, MILLISECONDS));
+                assertTrue(q.isEmpty());
+            }});
 
-        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 {
+                Thread.sleep(SHORT_DELAY_MS);
+                q.put(one);
+            }});
 
+        joinPool(executor);
     }
 
-    public void testPollInExecutor() {
+    /**
+     * a deserialized serialized queue is usable
+     */
+    public void testSerialization() throws Exception {
+        SynchronousQueue q = new SynchronousQueue();
+        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());
+    }
+
+    /**
+     * drainTo(null) throws NPE
+     */
+    public void testDrainToNull() {
+        SynchronousQueue q = new SynchronousQueue();
+        try {
+            q.drainTo(null);
+            shouldThrow();
+        } catch (NullPointerException success) {}
+    }
 
+    /**
+     * drainTo(this) throws IAE
+     */
+    public void testDrainToSelf() {
+        SynchronousQueue q = new SynchronousQueue();
+        try {
+            q.drainTo(q);
+            shouldThrow();
+        } catch (IllegalArgumentException success) {}
+    }
+
+    /**
+     * drainTo(c) of empty queue doesn't transfer elements
+     */
+    public void testDrainTo() {
+        SynchronousQueue q = new SynchronousQueue();
+        ArrayList l = new ArrayList();
+        q.drainTo(l);
+        assertEquals(q.size(), 0);
+        assertEquals(l.size(), 0);
+    }
+
+    /**
+     * drainTo empties queue, unblocking a waiting put.
+     */
+    public void testDrainToWithActivePut() throws InterruptedException {
         final SynchronousQueue q = new SynchronousQueue();
+        Thread t = new Thread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                q.put(new Integer(1));
+            }});
 
-        ExecutorService executor = Executors.newFixedThreadPool(2);
+        t.start();
+        ArrayList l = new ArrayList();
+        Thread.sleep(SHORT_DELAY_MS);
+        q.drainTo(l);
+        assertTrue(l.size() <= 1);
+        if (l.size() > 0)
+            assertEquals(l.get(0), new Integer(1));
+        t.join();
+        assertTrue(l.size() <= 1);
+    }
 
-        executor.execute(new Runnable() {
-            public void run() {
-                assertNull(q.poll());
-                try {
-                    assertTrue(null != q.poll(MEDIUM_DELAY_MS * 2, TimeUnit.MILLISECONDS));
-                    assertTrue(q.isEmpty());
-                }
-                catch (InterruptedException e) {
-                    fail("should not be interrupted");
-                }
-            }
-        });
+    /**
+     * drainTo(null, n) throws NPE
+     */
+    public void testDrainToNullN() {
+        SynchronousQueue q = new SynchronousQueue();
+        try {
+            q.drainTo(null, 0);
+            shouldThrow();
+        } catch (NullPointerException success) {}
+    }
 
-        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();
+    /**
+     * drainTo(this, n) throws IAE
+     */
+    public void testDrainToSelfN() {
+        SynchronousQueue q = new SynchronousQueue();
+        try {
+            q.drainTo(q, 0);
+            shouldThrow();
+        } catch (IllegalArgumentException success) {}
+    }
 
+    /**
+     * drainTo(c, n) empties up to n elements of queue into c
+     */
+    public void testDrainToN() throws InterruptedException {
+        final SynchronousQueue q = new SynchronousQueue();
+        Thread t1 = new Thread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                q.put(one);
+            }});
+
+        Thread t2 = new Thread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                q.put(two);
+            }});
+
+        t1.start();
+        t2.start();
+        ArrayList l = new ArrayList();
+        Thread.sleep(SHORT_DELAY_MS);
+        q.drainTo(l, 1);
+        assertEquals(1, l.size());
+        q.drainTo(l, 1);
+        assertEquals(2, l.size());
+        assertTrue(l.contains(one));
+        assertTrue(l.contains(two));
+        t1.join();
+        t2.join();
     }
 
 }