Brett Cannon's dummy_thread and dummy_threading modules (SF patch
622537), with some nitpicking editorial changes.
diff --git a/Lib/test/test_dummy_threading.py b/Lib/test/test_dummy_threading.py
new file mode 100644
index 0000000..cc8c0e3
--- /dev/null
+++ b/Lib/test/test_dummy_threading.py
@@ -0,0 +1,70 @@
+# Very rudimentary test of threading module
+
+# Create a bunch of threads, let each do some work, wait until all are done
+
+from test.test_support import verbose
+import random
+import dummy_threading as _threading
+import time
+
+
+class TestThread(_threading.Thread):
+    
+    def run(self):
+        global running
+        delay = random.random() * 2
+        if verbose:
+            print 'task', self.getName(), 'will run for', delay, 'sec'
+        sema.acquire()
+        mutex.acquire()
+        running = running + 1
+        if verbose:
+            print running, 'tasks are running'
+        mutex.release()
+        time.sleep(delay)
+        if verbose:
+            print 'task', self.getName(), 'done'
+        mutex.acquire()
+        running = running - 1
+        if verbose:
+            print self.getName(), 'is finished.', running, 'tasks are running'
+        mutex.release()
+        sema.release()
+
+def starttasks():
+    for i in range(numtasks):
+        t = TestThread(name="<thread %d>"%i)
+        threads.append(t)
+        t.start()
+
+
+def test_main():
+    # This takes about n/3 seconds to run (about n/3 clumps of tasks, times
+    # about 1 second per clump).
+    global numtasks
+    numtasks = 10
+
+    # no more than 3 of the 10 can run at once
+    global sema
+    sema = _threading.BoundedSemaphore(value=3)
+    global mutex
+    mutex = _threading.RLock()
+    global running
+    running = 0
+
+    global threads
+    threads = []
+    
+    starttasks()
+
+    if verbose:
+        print 'waiting for all tasks to complete'
+    for t in threads:
+        t.join()
+    if verbose:
+        print 'all tasks done'
+
+
+
+if __name__ == '__main__':
+    test_main()