cpython/Lib/test/test_queue.py

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# 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.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()