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"""PyUnit testing that threads honor our signal semantics"""
import unittest
import _thread as thread
import signal
import os
import sys
from test.support import run_unittest, TestSkipped
if sys.platform[:3] in ('win', 'os2'):
raise TestSkipped("Can't test signal on %s" % sys.platform)
process_pid = os.getpid()
signalled_all=thread.allocate_lock()
def registerSignals(for_usr1, for_usr2, for_alrm):
usr1 = signal.signal(signal.SIGUSR1, for_usr1)
usr2 = signal.signal(signal.SIGUSR2, for_usr2)
alrm = signal.signal(signal.SIGALRM, for_alrm)
return usr1, usr2, alrm
# The signal handler. Just note that the signal occurred and
# from who.
def handle_signals(sig,frame):
signal_blackboard[sig]['tripped'] += 1
signal_blackboard[sig]['tripped_by'] = thread.get_ident()
# a function that will be spawned as a separate thread.
def send_signals():
os.kill(process_pid, signal.SIGUSR1)
os.kill(process_pid, signal.SIGUSR2)
signalled_all.release()
class ThreadSignals(unittest.TestCase):
"""Test signal handling semantics of threads.
We spawn a thread, have the thread send two signals, and
wait for it to finish. Check that we got both signals
and that they were run by the main thread.
"""
def test_signals(self):
signalled_all.acquire()
self.spawnSignallingThread()
signalled_all.acquire()
# the signals that we asked the kernel to send
# will come back, but we don't know when.
# (it might even be after the thread exits
# and might be out of order.) If we haven't seen
# the signals yet, send yet another signal and
# wait for it return.
if signal_blackboard[signal.SIGUSR1]['tripped'] == 0 \
or signal_blackboard[signal.SIGUSR2]['tripped'] == 0:
signal.alarm(1)
signal.pause()
signal.alarm(0)
self.assertEqual( signal_blackboard[signal.SIGUSR1]['tripped'], 1)
self.assertEqual( signal_blackboard[signal.SIGUSR1]['tripped_by'],
thread.get_ident())
self.assertEqual( signal_blackboard[signal.SIGUSR2]['tripped'], 1)
self.assertEqual( signal_blackboard[signal.SIGUSR2]['tripped_by'],
thread.get_ident())
signalled_all.release()
def spawnSignallingThread(self):
thread.start_new_thread(send_signals, ())
def test_main():
global signal_blackboard
signal_blackboard = { signal.SIGUSR1 : {'tripped': 0, 'tripped_by': 0 },
signal.SIGUSR2 : {'tripped': 0, 'tripped_by': 0 },
signal.SIGALRM : {'tripped': 0, 'tripped_by': 0 } }
oldsigs = registerSignals(handle_signals, handle_signals, handle_signals)
try:
run_unittest(ThreadSignals)
finally:
registerSignals(*oldsigs)
if __name__ == '__main__':
test_main()
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