282 lines
9.3 KiB
Python
282 lines
9.3 KiB
Python
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# Some simple Queue module tests, plus some failure conditions
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# to ensure the Queue locks remain stable.
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import Queue
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import sys
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import threading
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import time
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from test.test_support import verify, TestFailed, verbose
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QUEUE_SIZE = 5
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# A thread to run a function that unclogs a blocked Queue.
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class _TriggerThread(threading.Thread):
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def __init__(self, fn, args):
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self.fn = fn
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self.args = args
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self.startedEvent = threading.Event()
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threading.Thread.__init__(self)
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def run(self):
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# The sleep isn't necessary, but is intended to give the blocking
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# function in the main thread a chance at actually blocking before
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# we unclog it. But if the sleep is longer than the timeout-based
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# tests wait in their blocking functions, those tests will fail.
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# So we give them much longer timeout values compared to the
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# sleep here (I aimed at 10 seconds for blocking functions --
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# they should never actually wait that long - they should make
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# progress as soon as we call self.fn()).
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time.sleep(0.1)
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self.startedEvent.set()
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self.fn(*self.args)
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# Execute a function that blocks, and in a separate thread, a function that
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# triggers the release. Returns the result of the blocking function.
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# Caution: block_func must guarantee to block until trigger_func is
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# called, and trigger_func must guarantee to change queue state so that
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# block_func can make enough progress to return. In particular, a
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# block_func that just raises an exception regardless of whether trigger_func
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# is called will lead to timing-dependent sporadic failures, and one of
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# those went rarely seen but undiagnosed for years. Now block_func
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# must be unexceptional. If block_func is supposed to raise an exception,
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# call _doExceptionalBlockingTest() instead.
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def _doBlockingTest(block_func, block_args, trigger_func, trigger_args):
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t = _TriggerThread(trigger_func, trigger_args)
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t.start()
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result = block_func(*block_args)
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# If block_func returned before our thread made the call, we failed!
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if not t.startedEvent.isSet():
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raise TestFailed("blocking function '%r' appeared not to block" %
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block_func)
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t.join(10) # make sure the thread terminates
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if t.isAlive():
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raise TestFailed("trigger function '%r' appeared to not return" %
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trigger_func)
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return result
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# Call this instead if block_func is supposed to raise an exception.
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def _doExceptionalBlockingTest(block_func, block_args, trigger_func,
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trigger_args, expected_exception_class):
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t = _TriggerThread(trigger_func, trigger_args)
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t.start()
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try:
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try:
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block_func(*block_args)
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except expected_exception_class:
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raise
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else:
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raise TestFailed("expected exception of kind %r" %
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expected_exception_class)
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finally:
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t.join(10) # make sure the thread terminates
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if t.isAlive():
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raise TestFailed("trigger function '%r' appeared to not return" %
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trigger_func)
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if not t.startedEvent.isSet():
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raise TestFailed("trigger thread ended but event never set")
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# A Queue subclass that can provoke failure at a moment's notice :)
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class FailingQueueException(Exception):
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pass
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class FailingQueue(Queue.Queue):
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def __init__(self, *args):
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self.fail_next_put = False
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self.fail_next_get = False
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Queue.Queue.__init__(self, *args)
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def _put(self, item):
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if self.fail_next_put:
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self.fail_next_put = False
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raise FailingQueueException, "You Lose"
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return Queue.Queue._put(self, item)
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def _get(self):
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if self.fail_next_get:
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self.fail_next_get = False
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raise FailingQueueException, "You Lose"
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return Queue.Queue._get(self)
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def FailingQueueTest(q):
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if not q.empty():
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raise RuntimeError, "Call this function with an empty queue"
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for i in range(QUEUE_SIZE-1):
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q.put(i)
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# Test a failing non-blocking put.
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q.fail_next_put = True
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try:
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q.put("oops", block=0)
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raise TestFailed("The queue didn't fail when it should have")
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except FailingQueueException:
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pass
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q.fail_next_put = True
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try:
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q.put("oops", timeout=0.1)
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raise TestFailed("The queue didn't fail when it should have")
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except FailingQueueException:
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pass
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q.put("last")
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verify(q.full(), "Queue should be full")
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# Test a failing blocking put
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q.fail_next_put = True
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try:
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_doBlockingTest(q.put, ("full",), q.get, ())
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raise TestFailed("The queue didn't fail when it should have")
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except FailingQueueException:
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pass
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# Check the Queue isn't damaged.
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# put failed, but get succeeded - re-add
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q.put("last")
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# Test a failing timeout put
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q.fail_next_put = True
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try:
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_doExceptionalBlockingTest(q.put, ("full", True, 10), q.get, (),
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FailingQueueException)
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raise TestFailed("The queue didn't fail when it should have")
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except FailingQueueException:
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pass
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# Check the Queue isn't damaged.
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# put failed, but get succeeded - re-add
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q.put("last")
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verify(q.full(), "Queue should be full")
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q.get()
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verify(not q.full(), "Queue should not be full")
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q.put("last")
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verify(q.full(), "Queue should be full")
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# Test a blocking put
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_doBlockingTest( q.put, ("full",), q.get, ())
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# Empty it
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for i in range(QUEUE_SIZE):
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q.get()
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verify(q.empty(), "Queue should be empty")
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q.put("first")
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q.fail_next_get = True
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try:
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q.get()
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raise TestFailed("The queue didn't fail when it should have")
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except FailingQueueException:
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pass
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verify(not q.empty(), "Queue should not be empty")
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q.fail_next_get = True
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try:
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q.get(timeout=0.1)
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raise TestFailed("The queue didn't fail when it should have")
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except FailingQueueException:
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pass
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verify(not q.empty(), "Queue should not be empty")
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q.get()
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verify(q.empty(), "Queue should be empty")
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q.fail_next_get = True
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try:
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_doExceptionalBlockingTest(q.get, (), q.put, ('empty',),
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FailingQueueException)
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raise TestFailed("The queue didn't fail when it should have")
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except FailingQueueException:
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pass
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# put succeeded, but get failed.
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verify(not q.empty(), "Queue should not be empty")
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q.get()
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verify(q.empty(), "Queue should be empty")
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def SimpleQueueTest(q):
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if not q.empty():
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raise RuntimeError, "Call this function with an empty queue"
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# I guess we better check things actually queue correctly a little :)
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q.put(111)
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q.put(222)
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verify(q.get() == 111 and q.get() == 222,
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"Didn't seem to queue the correct data!")
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for i in range(QUEUE_SIZE-1):
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q.put(i)
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verify(not q.empty(), "Queue should not be empty")
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verify(not q.full(), "Queue should not be full")
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q.put("last")
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verify(q.full(), "Queue should be full")
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try:
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q.put("full", block=0)
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raise TestFailed("Didn't appear to block with a full queue")
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except Queue.Full:
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pass
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try:
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q.put("full", timeout=0.01)
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raise TestFailed("Didn't appear to time-out with a full queue")
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except Queue.Full:
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pass
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# Test a blocking put
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_doBlockingTest(q.put, ("full",), q.get, ())
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_doBlockingTest(q.put, ("full", True, 10), q.get, ())
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# Empty it
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for i in range(QUEUE_SIZE):
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q.get()
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verify(q.empty(), "Queue should be empty")
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try:
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q.get(block=0)
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raise TestFailed("Didn't appear to block with an empty queue")
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except Queue.Empty:
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pass
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try:
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q.get(timeout=0.01)
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raise TestFailed("Didn't appear to time-out with an empty queue")
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except Queue.Empty:
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pass
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# Test a blocking get
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_doBlockingTest(q.get, (), q.put, ('empty',))
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_doBlockingTest(q.get, (True, 10), q.put, ('empty',))
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cum = 0
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cumlock = threading.Lock()
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def worker(q):
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global cum
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while True:
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x = q.get()
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if x is None:
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q.task_done()
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return
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cumlock.acquire()
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try:
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cum += x
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finally:
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cumlock.release()
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q.task_done()
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def QueueJoinTest(q):
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global cum
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cum = 0
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for i in (0,1):
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threading.Thread(target=worker, args=(q,)).start()
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for i in xrange(100):
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q.put(i)
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q.join()
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verify(cum==sum(range(100)), "q.join() did not block until all tasks were done")
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for i in (0,1):
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q.put(None) # instruct the threads to close
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q.join() # verify that you can join twice
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def QueueTaskDoneTest(q):
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try:
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q.task_done()
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except ValueError:
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pass
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else:
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raise TestFailed("Did not detect task count going negative")
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def test():
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q = Queue.Queue()
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QueueTaskDoneTest(q)
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QueueJoinTest(q)
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QueueJoinTest(q)
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QueueTaskDoneTest(q)
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q = Queue.Queue(QUEUE_SIZE)
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# Do it a couple of times on the same queue
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SimpleQueueTest(q)
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SimpleQueueTest(q)
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if verbose:
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print "Simple Queue tests seemed to work"
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q = FailingQueue(QUEUE_SIZE)
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FailingQueueTest(q)
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FailingQueueTest(q)
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if verbose:
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print "Failing Queue tests seemed to work"
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test()
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