cpython/Lib/test/test_threading.py

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# Very rudimentary test of threading module
import test.test_support
from test.test_support import verbose
import random
import sys
import threading
import thread
import time
import unittest
# A trivial mutable counter.
class Counter(object):
def __init__(self):
self.value = 0
def inc(self):
self.value += 1
def dec(self):
self.value -= 1
def get(self):
return self.value
class TestThread(threading.Thread):
def __init__(self, name, testcase, sema, mutex, nrunning):
threading.Thread.__init__(self, name=name)
self.testcase = testcase
self.sema = sema
self.mutex = mutex
self.nrunning = nrunning
def run(self):
delay = random.random() * 2
if verbose:
print 'task', self.getName(), 'will run for', delay, 'sec'
self.sema.acquire()
self.mutex.acquire()
self.nrunning.inc()
if verbose:
print self.nrunning.get(), 'tasks are running'
self.testcase.assert_(self.nrunning.get() <= 3)
self.mutex.release()
time.sleep(delay)
if verbose:
print 'task', self.getName(), 'done'
self.mutex.acquire()
self.nrunning.dec()
self.testcase.assert_(self.nrunning.get() >= 0)
if verbose:
print self.getName(), 'is finished.', self.nrunning.get(), \
'tasks are running'
self.mutex.release()
self.sema.release()
class ThreadTests(unittest.TestCase):
# Create a bunch of threads, let each do some work, wait until all are
# done.
def test_various_ops(self):
# This takes about n/3 seconds to run (about n/3 clumps of tasks,
# times about 1 second per clump).
NUMTASKS = 10
# no more than 3 of the 10 can run at once
sema = threading.BoundedSemaphore(value=3)
mutex = threading.RLock()
numrunning = Counter()
threads = []
for i in range(NUMTASKS):
t = TestThread("<thread %d>"%i, self, sema, mutex, numrunning)
threads.append(t)
t.start()
if verbose:
print 'waiting for all tasks to complete'
for t in threads:
t.join(NUMTASKS)
self.assert_(not t.isAlive())
if verbose:
print 'all tasks done'
self.assertEqual(numrunning.get(), 0)
# run with a small(ish) thread stack size (256kB)
def test_various_ops_small_stack(self):
if verbose:
print 'with 256kB thread stack size...'
try:
threading.stack_size(262144)
except thread.error:
if verbose:
print 'platform does not support changing thread stack size'
return
self.test_various_ops()
threading.stack_size(0)
# run with a large thread stack size (1MB)
def test_various_ops_large_stack(self):
if verbose:
print 'with 1MB thread stack size...'
try:
threading.stack_size(0x100000)
except thread.error:
if verbose:
print 'platform does not support changing thread stack size'
return
self.test_various_ops()
threading.stack_size(0)
def test_foreign_thread(self):
# Check that a "foreign" thread can use the threading module.
def f(mutex):
# Acquiring an RLock forces an entry for the foreign
# thread to get made in the threading._active map.
r = threading.RLock()
r.acquire()
r.release()
mutex.release()
mutex = threading.Lock()
mutex.acquire()
tid = thread.start_new_thread(f, (mutex,))
# Wait for the thread to finish.
mutex.acquire()
self.assert_(tid in threading._active)
self.assert_(isinstance(threading._active[tid],
threading._DummyThread))
del threading._active[tid]
# PyThreadState_SetAsyncExc() is a CPython-only gimmick, not (currently)
# exposed at the Python level. This test relies on ctypes to get at it.
def test_PyThreadState_SetAsyncExc(self):
try:
import ctypes
except ImportError:
if verbose:
print "test_PyThreadState_SetAsyncExc can't import ctypes"
return # can't do anything
set_async_exc = ctypes.pythonapi.PyThreadState_SetAsyncExc
class AsyncExc(Exception):
pass
exception = ctypes.py_object(AsyncExc)
# `worker_started` is set by the thread when it's inside a try/except
# block waiting to catch the asynchronously set AsyncExc exception.
# `worker_saw_exception` is set by the thread upon catching that
# exception.
worker_started = threading.Event()
worker_saw_exception = threading.Event()
class Worker(threading.Thread):
def run(self):
self.id = thread.get_ident()
self.finished = False
try:
while True:
worker_started.set()
time.sleep(0.1)
except AsyncExc:
self.finished = True
worker_saw_exception.set()
t = Worker()
t.setDaemon(True) # so if this fails, we don't hang Python at shutdown
t.start()
if verbose:
print " started worker thread"
# Try a thread id that doesn't make sense.
if verbose:
print " trying nonsensical thread id"
result = set_async_exc(ctypes.c_long(-1), exception)
self.assertEqual(result, 0) # no thread states modified
# Now raise an exception in the worker thread.
if verbose:
print " waiting for worker thread to get started"
worker_started.wait()
if verbose:
print " verifying worker hasn't exited"
self.assert_(not t.finished)
if verbose:
print " attempting to raise asynch exception in worker"
result = set_async_exc(ctypes.c_long(t.id), exception)
self.assertEqual(result, 1) # one thread state modified
if verbose:
print " waiting for worker to say it caught the exception"
worker_saw_exception.wait(timeout=10)
self.assert_(t.finished)
if verbose:
print " all OK -- joining worker"
if t.finished:
t.join()
# else the thread is still running, and we have no way to kill it
def test_finalize_runnning_thread(self):
# Issue 1402: the PyGILState_Ensure / _Release functions may be called
# very late on python exit: on deallocation of a running thread for
# example.
try:
import ctypes
except ImportError:
if verbose:
print("test_finalize_with_runnning_thread can't import ctypes")
return # can't do anything
import subprocess
rc = subprocess.call([sys.executable, "-c", """if 1:
import ctypes, sys, time, thread
# Module globals are cleared before __del__ is run
# So we save the functions in class dict
class C:
ensure = ctypes.pythonapi.PyGILState_Ensure
release = ctypes.pythonapi.PyGILState_Release
def __del__(self):
state = self.ensure()
self.release(state)
def waitingThread():
x = C()
time.sleep(100)
thread.start_new_thread(waitingThread, ())
time.sleep(1) # be sure the other thread is waiting
sys.exit(42)
"""])
self.assertEqual(rc, 42)
class ThreadingExceptionTests(unittest.TestCase):
# A RuntimeError should be raised if Thread.start() is called
# multiple times.
def test_start_thread_again(self):
thread = threading.Thread()
thread.start()
self.assertRaises(RuntimeError, thread.start)
def test_releasing_unacquired_rlock(self):
rlock = threading.RLock()
self.assertRaises(RuntimeError, rlock.release)
def test_waiting_on_unacquired_condition(self):
cond = threading.Condition()
self.assertRaises(RuntimeError, cond.wait)
def test_notify_on_unacquired_condition(self):
cond = threading.Condition()
self.assertRaises(RuntimeError, cond.notify)
def test_semaphore_with_negative_value(self):
self.assertRaises(ValueError, threading.Semaphore, value = -1)
self.assertRaises(ValueError, threading.Semaphore, value = -sys.maxint)
def test_joining_current_thread(self):
currentThread = threading.currentThread()
self.assertRaises(RuntimeError, currentThread.join);
def test_joining_inactive_thread(self):
thread = threading.Thread()
self.assertRaises(RuntimeError, thread.join)
def test_daemonize_active_thread(self):
thread = threading.Thread()
thread.start()
self.assertRaises(RuntimeError, thread.setDaemon, True)
def test_main():
test.test_support.run_unittest(ThreadTests,
ThreadingExceptionTests)
if __name__ == "__main__":
test_main()