cpython/Lib/test/test_threading.py

490 lines
17 KiB
Python

# Very rudimentary test of threading module
import test.support
from test.support import verbose, catch_warning
import random
import re
import sys
import threading
import _thread
import time
import unittest
import weakref
# 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() / 10000.0
if verbose:
print('task %s will run for %.1f usec' %
(self.name, delay * 1e6))
with self.sema:
with self.mutex:
self.nrunning.inc()
if verbose:
print(self.nrunning.get(), 'tasks are running')
self.testcase.assert_(self.nrunning.get() <= 3)
time.sleep(delay)
if verbose:
print('task', self.name, 'done')
with self.mutex:
self.nrunning.dec()
self.testcase.assert_(self.nrunning.get() >= 0)
if verbose:
print('%s is finished. %d tasks are running' %
(self.name, self.nrunning.get()))
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)
self.failUnlessEqual(t.ident, None)
self.assert_(re.match('<TestThread\(.*, initial\)>', repr(t)))
t.start()
if verbose:
print('waiting for all tasks to complete')
for t in threads:
t.join(NUMTASKS)
self.assert_(not t.is_alive())
self.failIfEqual(t.ident, 0)
self.assert_(re.match('<TestThread\(.*, \w+ -?\d+\)>', repr(t)))
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.daemon = 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
# This lock is used as a simple event variable.
ready = _thread.allocate_lock()
ready.acquire()
# 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()
ready.release()
time.sleep(100)
_thread.start_new_thread(waitingThread, ())
ready.acquire() # Be sure the other thread is waiting.
sys.exit(42)
"""])
self.assertEqual(rc, 42)
def test_finalize_with_trace(self):
# Issue1733757
# Avoid a deadlock when sys.settrace steps into threading._shutdown
import subprocess
rc = subprocess.call([sys.executable, "-c", """if 1:
import sys, threading
# A deadlock-killer, to prevent the
# testsuite to hang forever
def killer():
import os, time
time.sleep(2)
print('program blocked; aborting')
os._exit(2)
t = threading.Thread(target=killer)
t.daemon = True
t.start()
# This is the trace function
def func(frame, event, arg):
threading.current_thread()
return func
sys.settrace(func)
"""])
self.failIf(rc == 2, "interpreted was blocked")
self.failUnless(rc == 0, "Unexpected error")
def test_enumerate_after_join(self):
# Try hard to trigger #1703448: a thread is still returned in
# threading.enumerate() after it has been join()ed.
enum = threading.enumerate
old_interval = sys.getcheckinterval()
try:
for i in range(1, 100):
# Try a couple times at each thread-switching interval
# to get more interleavings.
sys.setcheckinterval(i // 5)
t = threading.Thread(target=lambda: None)
t.start()
t.join()
l = enum()
self.assertFalse(t in l,
"#1703448 triggered after %d trials: %s" % (i, l))
finally:
sys.setcheckinterval(old_interval)
def test_no_refcycle_through_target(self):
class RunSelfFunction(object):
def __init__(self, should_raise):
# The links in this refcycle from Thread back to self
# should be cleaned up when the thread completes.
self.should_raise = should_raise
self.thread = threading.Thread(target=self._run,
args=(self,),
kwargs={'yet_another':self})
self.thread.start()
def _run(self, other_ref, yet_another):
if self.should_raise:
raise SystemExit
cyclic_object = RunSelfFunction(should_raise=False)
weak_cyclic_object = weakref.ref(cyclic_object)
cyclic_object.thread.join()
del cyclic_object
self.assertEquals(None, weak_cyclic_object(),
msg=('%d references still around' %
sys.getrefcount(weak_cyclic_object())))
raising_cyclic_object = RunSelfFunction(should_raise=True)
weak_raising_cyclic_object = weakref.ref(raising_cyclic_object)
raising_cyclic_object.thread.join()
del raising_cyclic_object
self.assertEquals(None, weak_raising_cyclic_object(),
msg=('%d references still around' %
sys.getrefcount(weak_raising_cyclic_object())))
def test_pep8ified_threading(self):
def check(_, w, msg):
self.assertEqual(str(w.message), msg)
t = threading.Thread()
with catch_warning() as w:
try:
del threading.__warningregistry__
except AttributeError:
pass
msg = "isDaemon() is deprecated in favor of the " \
"Thread.daemon property"
check(t.isDaemon(), w, msg)
w.reset()
msg = "setDaemon() is deprecated in favor of the " \
"Thread.daemon property"
check(t.setDaemon(True), w, msg)
w.reset()
msg = "getName() is deprecated in favor of the " \
"Thread.name property"
check(t.getName(), w, msg)
w.reset()
msg = "setName() is deprecated in favor of the " \
"Thread.name property"
check(t.setName("name"), w, msg)
w.reset()
msg = "isAlive() is deprecated in favor of is_alive()"
check(t.isAlive(), w, msg)
w.reset()
e = threading.Event()
msg = "isSet() is deprecated in favor of is_set()"
check(e.isSet(), w, msg)
w.reset()
msg = "currentThread() is deprecated in favor of current_thread()"
check(threading.currentThread(), w, msg)
w.reset()
msg = "activeCount() is deprecated in favor of active_count()"
check(threading.activeCount(), w, msg)
class ThreadJoinOnShutdown(unittest.TestCase):
def _run_and_join(self, script):
script = """if 1:
import sys, os, time, threading
# a thread, which waits for the main program to terminate
def joiningfunc(mainthread):
mainthread.join()
print('end of thread')
\n""" + script
import subprocess
p = subprocess.Popen([sys.executable, "-c", script], stdout=subprocess.PIPE)
rc = p.wait()
data = p.stdout.read().decode().replace('\r', '')
self.assertEqual(data, "end of main\nend of thread\n")
self.failIf(rc == 2, "interpreter was blocked")
self.failUnless(rc == 0, "Unexpected error")
def test_1_join_on_shutdown(self):
# The usual case: on exit, wait for a non-daemon thread
script = """if 1:
import os
t = threading.Thread(target=joiningfunc,
args=(threading.current_thread(),))
t.start()
time.sleep(0.1)
print('end of main')
"""
self._run_and_join(script)
def test_2_join_in_forked_process(self):
# Like the test above, but from a forked interpreter
import os
if not hasattr(os, 'fork'):
return
script = """if 1:
childpid = os.fork()
if childpid != 0:
os.waitpid(childpid, 0)
sys.exit(0)
t = threading.Thread(target=joiningfunc,
args=(threading.current_thread(),))
t.start()
print('end of main')
"""
self._run_and_join(script)
# XXX This test hangs!
def Xtest_3_join_in_forked_from_thread(self):
# Like the test above, but fork() was called from a worker thread
# In the forked process, the main Thread object must be marked as stopped.
import os
if not hasattr(os, 'fork'):
return
script = """if 1:
main_thread = threading.current_thread()
def worker():
childpid = os.fork()
if childpid != 0:
os.waitpid(childpid, 0)
sys.exit(0)
t = threading.Thread(target=joiningfunc,
args=(main_thread,))
print('end of main')
t.start()
t.join() # Should not block: main_thread is already stopped
w = threading.Thread(target=worker)
w.start()
"""
self._run_and_join(script)
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.maxsize)
def test_joining_current_thread(self):
current_thread = threading.current_thread()
self.assertRaises(RuntimeError, current_thread.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, setattr, thread, "daemon", True)
def test_main():
test.support.run_unittest(ThreadTests,
ThreadJoinOnShutdown,
ThreadingExceptionTests,
)
if __name__ == "__main__":
test_main()