[Python-checkins] python/dist/src/Lib/test test_queue.py,NONE,1.1

2002年4月18日 17:11:37 -0700

Update of /cvsroot/python/python/dist/src/Lib/test
In directory usw-pr-cvs1:/tmp/cvs-serv3478/test
Added Files:
	test_queue.py 
Log Message:
Fix bug 544473 - "Queue module can deadlock".
Use try/finally to ensure all Queue locks remain stable.
Includes test case. Bugfix candidate.
--- NEW FILE: test_queue.py ---
# Some simple Queue module tests, plus some failure conditions
# to ensure the Queue locks remain stable
import Queue
import sys
import threading
import time
from test_support import verify, TestFailed, verbose
queue_size = 5
# Execute a function that blocks, and in a seperate thread, a function that
# triggers the release. Returns the result of the blocking function.
class _TriggerThread(threading.Thread):
 def __init__(self, fn, args):
 self.fn = fn
 self.args = args
 self.startedEvent = threading.Event()
 threading.Thread.__init__(self)
 def run(self):
 time.sleep(.1)
 self.startedEvent.set()
 self.fn(*self.args)
def _doBlockingTest( block_func, block_args, trigger_func, trigger_args):
 t = _TriggerThread(trigger_func, trigger_args)
 t.start()
 try:
 return block_func(*block_args)
 finally:
 # If we unblocked before our thread made the call, we failed!
 if not t.startedEvent.isSet():
 raise TestFailed("blocking function '%r' appeared not to block" % (block_func,))
 t.join(1) # make sure the thread terminates
 if t.isAlive():
 raise TestFailed("trigger function '%r' appeared to not return" % (trigger_func,))
# A Queue subclass that can provoke failure at a moment's notice :)
class FailingQueueException(Exception):
 pass
class FailingQueue(Queue.Queue):
 def __init__(self, *args):
 self.fail_next_put = False
 self.fail_next_get = False
 Queue.Queue.__init__(self, *args)
 def _put(self, item):
 if self.fail_next_put:
 self.fail_next_put = False
 raise FailingQueueException, "You Lose"
 return Queue.Queue._put(self, item)
 def _get(self):
 if self.fail_next_get:
 self.fail_next_get = False
 raise FailingQueueException, "You Lose"
 return Queue.Queue._get(self)
def FailingQueueTest(q):
 if not q.empty():
 raise RuntimeError, "Call this function with an empty queue"
 for i in range(queue_size-1):
 q.put(i)
 q.fail_next_put = True
 # Test a failing non-blocking put.
 try:
 q.put("oops", block=0)
 raise TestFailed("The queue didn't fail when it should have")
 except FailingQueueException:
 pass
 q.put("last")
 verify(q.full(), "Queue should be full")
 q.fail_next_put = True
 # Test a failing blocking put
 try:
 _doBlockingTest( q.put, ("full",), q.get, ())
 raise TestFailed("The queue didn't fail when it should have")
 except FailingQueueException:
 pass
 # Check the Queue isn't damaged.
 # put failed, but get succeeded - re-add
 q.put("last")
 verify(q.full(), "Queue should be full")
 q.get()
 verify(not q.full(), "Queue should not be full")
 q.put("last")
 verify(q.full(), "Queue should be full")
 # Test a blocking put
 _doBlockingTest( q.put, ("full",), q.get, ())
 # Empty it
 for i in range(queue_size):
 q.get()
 verify(q.empty(), "Queue should be empty")
 q.put("first")
 q.fail_next_get = True
 try:
 q.get()
 raise TestFailed("The queue didn't fail when it should have")
 except FailingQueueException:
 pass
 verify(not q.empty(), "Queue should not be empty")
 q.get()
 verify(q.empty(), "Queue should be empty")
 q.fail_next_get = True
 try:
 _doBlockingTest( q.get, (), q.put, ('empty',))
 raise TestFailed("The queue didn't fail when it should have")
 except FailingQueueException:
 pass
 # put succeeded, but get failed.
 verify(not q.empty(), "Queue should not be empty")
 q.get()
 verify(q.empty(), "Queue should be empty")
def SimpleQueueTest(q):
 if not q.empty():
 raise RuntimeError, "Call this function with an empty queue"
 # I guess we better check things actually queue correctly a little :)
 q.put(111)
 q.put(222)
 verify(q.get()==111 and q.get()==222, "Didn't seem to queue the correct data!")
 for i in range(queue_size-1):
 q.put(i)
 verify(not q.full(), "Queue should not be full")
 q.put("last")
 verify(q.full(), "Queue should be full")
 try:
 q.put("full", block=0)
 raise TestFailed("Didn't appear to block with a full queue")
 except Queue.Full:
 pass
 # Test a blocking put
 _doBlockingTest( q.put, ("full",), q.get, ())
 # Empty it
 for i in range(queue_size):
 q.get()
 verify(q.empty(), "Queue should be empty")
 try:
 q.get(block=0)
 raise TestFailed("Didn't appear to block with an empty queue")
 except Queue.Empty:
 pass
 # Test a blocking get
 _doBlockingTest( q.get, (), q.put, ('empty',))
def test():
 q=Queue.Queue(queue_size)
 # Do it a couple of times on the same queue
 SimpleQueueTest(q)
 SimpleQueueTest(q)
 if verbose:
 print "Simple Queue tests seemed to work"
 q = FailingQueue(queue_size)
 FailingQueueTest(q)
 FailingQueueTest(q)
 if verbose:
 print "Failing Queue tests seemed to work"
test()