cpython/Lib/test/test_thread.py

279 lines
8.9 KiB
Python

import os
import unittest
import random
from test import support
from test.support import threading_helper
import _thread as thread
import time
import warnings
import weakref
from test import lock_tests
threading_helper.requires_working_threading(module=True)
NUMTASKS = 10
NUMTRIPS = 3
_print_mutex = thread.allocate_lock()
def verbose_print(arg):
"""Helper function for printing out debugging output."""
if support.verbose:
with _print_mutex:
print(arg)
class BasicThreadTest(unittest.TestCase):
def setUp(self):
self.done_mutex = thread.allocate_lock()
self.done_mutex.acquire()
self.running_mutex = thread.allocate_lock()
self.random_mutex = thread.allocate_lock()
self.created = 0
self.running = 0
self.next_ident = 0
key = threading_helper.threading_setup()
self.addCleanup(threading_helper.threading_cleanup, *key)
class ThreadRunningTests(BasicThreadTest):
def newtask(self):
with self.running_mutex:
self.next_ident += 1
verbose_print("creating task %s" % self.next_ident)
thread.start_new_thread(self.task, (self.next_ident,))
self.created += 1
self.running += 1
def task(self, ident):
with self.random_mutex:
delay = random.random() / 10000.0
verbose_print("task %s will run for %sus" % (ident, round(delay*1e6)))
time.sleep(delay)
verbose_print("task %s done" % ident)
with self.running_mutex:
self.running -= 1
if self.created == NUMTASKS and self.running == 0:
self.done_mutex.release()
def test_starting_threads(self):
with threading_helper.wait_threads_exit():
# Basic test for thread creation.
for i in range(NUMTASKS):
self.newtask()
verbose_print("waiting for tasks to complete...")
self.done_mutex.acquire()
verbose_print("all tasks done")
def test_stack_size(self):
# Various stack size tests.
self.assertEqual(thread.stack_size(), 0, "initial stack size is not 0")
thread.stack_size(0)
self.assertEqual(thread.stack_size(), 0, "stack_size not reset to default")
@unittest.skipIf(os.name not in ("nt", "posix"), 'test meant for nt and posix')
def test_nt_and_posix_stack_size(self):
try:
thread.stack_size(4096)
except ValueError:
verbose_print("caught expected ValueError setting "
"stack_size(4096)")
except thread.error:
self.skipTest("platform does not support changing thread stack "
"size")
fail_msg = "stack_size(%d) failed - should succeed"
for tss in (262144, 0x100000, 0):
thread.stack_size(tss)
self.assertEqual(thread.stack_size(), tss, fail_msg % tss)
verbose_print("successfully set stack_size(%d)" % tss)
for tss in (262144, 0x100000):
verbose_print("trying stack_size = (%d)" % tss)
self.next_ident = 0
self.created = 0
with threading_helper.wait_threads_exit():
for i in range(NUMTASKS):
self.newtask()
verbose_print("waiting for all tasks to complete")
self.done_mutex.acquire()
verbose_print("all tasks done")
thread.stack_size(0)
def test__count(self):
# Test the _count() function.
orig = thread._count()
mut = thread.allocate_lock()
mut.acquire()
started = []
def task():
started.append(None)
mut.acquire()
mut.release()
with threading_helper.wait_threads_exit():
thread.start_new_thread(task, ())
for _ in support.sleeping_retry(support.LONG_TIMEOUT):
if started:
break
self.assertEqual(thread._count(), orig + 1)
# Allow the task to finish.
mut.release()
# The only reliable way to be sure that the thread ended from the
# interpreter's point of view is to wait for the function object to
# be destroyed.
done = []
wr = weakref.ref(task, lambda _: done.append(None))
del task
for _ in support.sleeping_retry(support.LONG_TIMEOUT):
if done:
break
support.gc_collect() # For PyPy or other GCs.
self.assertEqual(thread._count(), orig)
def test_unraisable_exception(self):
def task():
started.release()
raise ValueError("task failed")
started = thread.allocate_lock()
with support.catch_unraisable_exception() as cm:
with threading_helper.wait_threads_exit():
started.acquire()
thread.start_new_thread(task, ())
started.acquire()
self.assertEqual(str(cm.unraisable.exc_value), "task failed")
self.assertIs(cm.unraisable.object, task)
self.assertEqual(cm.unraisable.err_msg,
"Exception ignored in thread started by")
self.assertIsNotNone(cm.unraisable.exc_traceback)
class Barrier:
def __init__(self, num_threads):
self.num_threads = num_threads
self.waiting = 0
self.checkin_mutex = thread.allocate_lock()
self.checkout_mutex = thread.allocate_lock()
self.checkout_mutex.acquire()
def enter(self):
self.checkin_mutex.acquire()
self.waiting = self.waiting + 1
if self.waiting == self.num_threads:
self.waiting = self.num_threads - 1
self.checkout_mutex.release()
return
self.checkin_mutex.release()
self.checkout_mutex.acquire()
self.waiting = self.waiting - 1
if self.waiting == 0:
self.checkin_mutex.release()
return
self.checkout_mutex.release()
class BarrierTest(BasicThreadTest):
def test_barrier(self):
with threading_helper.wait_threads_exit():
self.bar = Barrier(NUMTASKS)
self.running = NUMTASKS
for i in range(NUMTASKS):
thread.start_new_thread(self.task2, (i,))
verbose_print("waiting for tasks to end")
self.done_mutex.acquire()
verbose_print("tasks done")
def task2(self, ident):
for i in range(NUMTRIPS):
if ident == 0:
# give it a good chance to enter the next
# barrier before the others are all out
# of the current one
delay = 0
else:
with self.random_mutex:
delay = random.random() / 10000.0
verbose_print("task %s will run for %sus" %
(ident, round(delay * 1e6)))
time.sleep(delay)
verbose_print("task %s entering %s" % (ident, i))
self.bar.enter()
verbose_print("task %s leaving barrier" % ident)
with self.running_mutex:
self.running -= 1
# Must release mutex before releasing done, else the main thread can
# exit and set mutex to None as part of global teardown; then
# mutex.release() raises AttributeError.
finished = self.running == 0
if finished:
self.done_mutex.release()
class LockTests(lock_tests.LockTests):
locktype = thread.allocate_lock
class TestForkInThread(unittest.TestCase):
def setUp(self):
self.read_fd, self.write_fd = os.pipe()
@support.requires_fork()
@threading_helper.reap_threads
def test_forkinthread(self):
pid = None
def fork_thread(read_fd, write_fd):
nonlocal pid
# Ignore the warning about fork with threads.
with warnings.catch_warnings(category=DeprecationWarning,
action="ignore"):
# fork in a thread (DANGER, undefined per POSIX)
if (pid := os.fork()):
# parent process
return
# child process
try:
os.close(read_fd)
os.write(write_fd, b"OK")
finally:
os._exit(0)
with threading_helper.wait_threads_exit():
thread.start_new_thread(fork_thread, (self.read_fd, self.write_fd))
self.assertEqual(os.read(self.read_fd, 2), b"OK")
os.close(self.write_fd)
self.assertIsNotNone(pid)
support.wait_process(pid, exitcode=0)
def tearDown(self):
try:
os.close(self.read_fd)
except OSError:
pass
try:
os.close(self.write_fd)
except OSError:
pass
if __name__ == "__main__":
unittest.main()