SF Patch #1455676: Simplify using Queues with daemon consumer threads

Adds join() and task_done() methods to track when all enqueued tasks have
been gotten and fully processed by daemon consumer threads.

Lib/test/test_queue.py

@@ -221,7 +221,37 @@ def SimpleQueueTest(q):
     _doBlockingTest(q.get, (), q.put, ('empty',))
     _doBlockingTest(q.get, (True, 10), q.put, ('empty',))
 
+cum = 0
+cumlock = threading.Lock()
+
+def worker(q):
+    global cum
+    while True:
+        x = q.get()
+        cumlock.acquire()
+        try:
+            cum += x
+        finally:
+            cumlock.release()
+        q.task_done()
+    
+def QueueJoinTest(q):
+    global cum
+    cum = 0
+    for i in (0,1):
+        t = threading.Thread(target=worker, args=(q,))
+        t.setDaemon(True)
+        t.start()
+    for i in xrange(100):
+        q.put(i)
+    q.join()
+    verify(cum==sum(range(100)), "q.join() did not block until all tasks were done")
+
 def test():
+    q = Queue.Queue()
+    QueueJoinTest(q)
+    QueueJoinTest(q)
+
     q = Queue.Queue(QUEUE_SIZE)
     # Do it a couple of times on the same queue
     SimpleQueueTest(q)