| # Very rudimentary test of threading module |
| |
| import test.support |
| from test.support import verbose |
| import os |
| import random |
| import re |
| import sys |
| import threading |
| import _thread |
| import time |
| import unittest |
| import weakref |
| import subprocess |
| |
| from test import lock_tests |
| |
| # 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.assertTrue(self.nrunning.get() <= 3) |
| |
| time.sleep(delay) |
| if verbose: |
| print('task', self.name, 'done') |
| |
| with self.mutex: |
| self.nrunning.dec() |
| self.testcase.assertTrue(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.assertEqual(t.ident, None) |
| self.assertTrue(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.assertTrue(not t.is_alive()) |
| self.assertNotEqual(t.ident, 0) |
| self.assertFalse(t.ident is None) |
| self.assertTrue(re.match('<TestThread\(.*, \w+ -?\d+\)>', repr(t))) |
| if verbose: |
| print('all tasks done') |
| self.assertEqual(numrunning.get(), 0) |
| |
| def test_ident_of_no_threading_threads(self): |
| # The ident still must work for the main thread and dummy threads. |
| self.assertFalse(threading.currentThread().ident is None) |
| def f(): |
| ident.append(threading.currentThread().ident) |
| done.set() |
| done = threading.Event() |
| ident = [] |
| _thread.start_new_thread(f, ()) |
| done.wait() |
| self.assertFalse(ident[0] is None) |
| # Kill the "immortal" _DummyThread |
| del threading._active[ident[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): |
| # Calling current_thread() forces an entry for the foreign |
| # thread to get made in the threading._active map. |
| threading.current_thread() |
| mutex.release() |
| |
| mutex = threading.Lock() |
| mutex.acquire() |
| tid = _thread.start_new_thread(f, (mutex,)) |
| # Wait for the thread to finish. |
| mutex.acquire() |
| self.assertTrue(tid in threading._active) |
| self.assertTrue(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") |
| ret = worker_started.wait() |
| self.assertTrue(ret) |
| if verbose: |
| print(" verifying worker hasn't exited") |
| self.assertTrue(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.assertTrue(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_limbo_cleanup(self): |
| # Issue 7481: Failure to start thread should cleanup the limbo map. |
| def fail_new_thread(*args): |
| raise threading.ThreadError() |
| _start_new_thread = threading._start_new_thread |
| threading._start_new_thread = fail_new_thread |
| try: |
| t = threading.Thread(target=lambda: None) |
| self.assertRaises(threading.ThreadError, t.start) |
| self.assertFalse( |
| t in threading._limbo, |
| "Failed to cleanup _limbo map on failure of Thread.start().") |
| finally: |
| threading._start_new_thread = _start_new_thread |
| |
| 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 |
| |
| 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 |
| p = subprocess.Popen([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) |
| """], |
| stdout=subprocess.PIPE, |
| stderr=subprocess.PIPE) |
| stdout, stderr = p.communicate() |
| rc = p.returncode |
| self.assertFalse(rc == 2, "interpreted was blocked") |
| self.assertTrue(rc == 0, |
| "Unexpected error: " + ascii(stderr)) |
| |
| def test_join_nondaemon_on_shutdown(self): |
| # Issue 1722344 |
| # Raising SystemExit skipped threading._shutdown |
| p = subprocess.Popen([sys.executable, "-c", """if 1: |
| import threading |
| from time import sleep |
| |
| def child(): |
| sleep(1) |
| # As a non-daemon thread we SHOULD wake up and nothing |
| # should be torn down yet |
| print("Woke up, sleep function is:", sleep) |
| |
| threading.Thread(target=child).start() |
| raise SystemExit |
| """], |
| stdout=subprocess.PIPE, |
| stderr=subprocess.PIPE) |
| stdout, stderr = p.communicate() |
| self.assertEqual(stdout.strip(), |
| b"Woke up, sleep function is: <built-in function sleep>") |
| stderr = re.sub(br"^\[\d+ refs\]", b"", stderr, re.MULTILINE).strip() |
| self.assertEqual(stderr, b"") |
| |
| 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.assertEqual(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.assertEqual(None, weak_raising_cyclic_object(), |
| msg=('%d references still around' % |
| sys.getrefcount(weak_raising_cyclic_object()))) |
| |
| def test_old_threading_api(self): |
| # Just a quick sanity check to make sure the old method names are |
| # still present |
| t = threading.Thread() |
| t.isDaemon() |
| t.setDaemon(True) |
| t.getName() |
| t.setName("name") |
| t.isAlive() |
| e = threading.Event() |
| e.isSet() |
| threading.activeCount() |
| |
| |
| 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') |
| # stdout is fully buffered because not a tty, we have to flush |
| # before exit. |
| sys.stdout.flush() |
| \n""" + script |
| |
| p = subprocess.Popen([sys.executable, "-c", script], stdout=subprocess.PIPE) |
| rc = p.wait() |
| data = p.stdout.read().decode().replace('\r', '') |
| p.stdout.close() |
| self.assertEqual(data, "end of main\nend of thread\n") |
| self.assertFalse(rc == 2, "interpreter was blocked") |
| self.assertTrue(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) |
| |
| def test_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 |
| # Skip platforms with known problems forking from a worker thread. |
| # See http://bugs.python.org/issue3863. |
| if sys.platform in ('freebsd4', 'freebsd5', 'freebsd6', 'netbsd5', |
| 'os2emx'): |
| print('Skipping test_3_join_in_forked_from_thread' |
| ' due to known OS bugs on', sys.platform, file=sys.stderr) |
| 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) |
| |
| def assertScriptHasOutput(self, script, expected_output): |
| p = subprocess.Popen([sys.executable, "-c", script], |
| stdout=subprocess.PIPE) |
| rc = p.wait() |
| data = p.stdout.read().decode().replace('\r', '') |
| self.assertEqual(rc, 0, "Unexpected error") |
| self.assertEqual(data, expected_output) |
| |
| @unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()") |
| def test_4_joining_across_fork_in_worker_thread(self): |
| # There used to be a possible deadlock when forking from a child |
| # thread. See http://bugs.python.org/issue6643. |
| |
| # Skip platforms with known problems forking from a worker thread. |
| # See http://bugs.python.org/issue3863. |
| if sys.platform in ('freebsd4', 'freebsd5', 'freebsd6', 'os2emx'): |
| raise unittest.SkipTest('due to known OS bugs on ' + sys.platform) |
| |
| # The script takes the following steps: |
| # - The main thread in the parent process starts a new thread and then |
| # tries to join it. |
| # - The join operation acquires the Lock inside the thread's _block |
| # Condition. (See threading.py:Thread.join().) |
| # - We stub out the acquire method on the condition to force it to wait |
| # until the child thread forks. (See LOCK ACQUIRED HERE) |
| # - The child thread forks. (See LOCK HELD and WORKER THREAD FORKS |
| # HERE) |
| # - The main thread of the parent process enters Condition.wait(), |
| # which releases the lock on the child thread. |
| # - The child process returns. Without the necessary fix, when the |
| # main thread of the child process (which used to be the child thread |
| # in the parent process) attempts to exit, it will try to acquire the |
| # lock in the Thread._block Condition object and hang, because the |
| # lock was held across the fork. |
| |
| script = """if 1: |
| import os, time, threading |
| |
| finish_join = False |
| start_fork = False |
| |
| def worker(): |
| # Wait until this thread's lock is acquired before forking to |
| # create the deadlock. |
| global finish_join |
| while not start_fork: |
| time.sleep(0.01) |
| # LOCK HELD: Main thread holds lock across this call. |
| childpid = os.fork() |
| finish_join = True |
| if childpid != 0: |
| # Parent process just waits for child. |
| os.waitpid(childpid, 0) |
| # Child process should just return. |
| |
| w = threading.Thread(target=worker) |
| |
| # Stub out the private condition variable's lock acquire method. |
| # This acquires the lock and then waits until the child has forked |
| # before returning, which will release the lock soon after. If |
| # someone else tries to fix this test case by acquiring this lock |
| # before forking instead of resetting it, the test case will |
| # deadlock when it shouldn't. |
| condition = w._block |
| orig_acquire = condition.acquire |
| call_count_lock = threading.Lock() |
| call_count = 0 |
| def my_acquire(): |
| global call_count |
| global start_fork |
| orig_acquire() # LOCK ACQUIRED HERE |
| start_fork = True |
| if call_count == 0: |
| while not finish_join: |
| time.sleep(0.01) # WORKER THREAD FORKS HERE |
| with call_count_lock: |
| call_count += 1 |
| condition.acquire = my_acquire |
| |
| w.start() |
| w.join() |
| print('end of main') |
| """ |
| self.assertScriptHasOutput(script, "end of main\n") |
| |
| @unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()") |
| def test_5_clear_waiter_locks_to_avoid_crash(self): |
| # Check that a spawned thread that forks doesn't segfault on certain |
| # platforms, namely OS X. This used to happen if there was a waiter |
| # lock in the thread's condition variable's waiters list. Even though |
| # we know the lock will be held across the fork, it is not safe to |
| # release locks held across forks on all platforms, so releasing the |
| # waiter lock caused a segfault on OS X. Furthermore, since locks on |
| # OS X are (as of this writing) implemented with a mutex + condition |
| # variable instead of a semaphore, while we know that the Python-level |
| # lock will be acquired, we can't know if the internal mutex will be |
| # acquired at the time of the fork. |
| |
| # Skip platforms with known problems forking from a worker thread. |
| # See http://bugs.python.org/issue3863. |
| if sys.platform in ('freebsd4', 'freebsd5', 'freebsd6', 'os2emx'): |
| raise unittest.SkipTest('due to known OS bugs on ' + sys.platform) |
| script = """if True: |
| import os, time, threading |
| |
| start_fork = False |
| |
| def worker(): |
| # Wait until the main thread has attempted to join this thread |
| # before continuing. |
| while not start_fork: |
| time.sleep(0.01) |
| childpid = os.fork() |
| if childpid != 0: |
| # Parent process just waits for child. |
| (cpid, rc) = os.waitpid(childpid, 0) |
| assert cpid == childpid |
| assert rc == 0 |
| print('end of worker thread') |
| else: |
| # Child process should just return. |
| pass |
| |
| w = threading.Thread(target=worker) |
| |
| # Stub out the private condition variable's _release_save method. |
| # This releases the condition's lock and flips the global that |
| # causes the worker to fork. At this point, the problematic waiter |
| # lock has been acquired once by the waiter and has been put onto |
| # the waiters list. |
| condition = w._block |
| orig_release_save = condition._release_save |
| def my_release_save(): |
| global start_fork |
| orig_release_save() |
| # Waiter lock held here, condition lock released. |
| start_fork = True |
| condition._release_save = my_release_save |
| |
| w.start() |
| w.join() |
| print('end of main thread') |
| """ |
| output = "end of worker thread\nend of main thread\n" |
| self.assertScriptHasOutput(script, output) |
| |
| |
| 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_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) |
| |
| |
| class LockTests(lock_tests.LockTests): |
| locktype = staticmethod(threading.Lock) |
| |
| class RLockTests(lock_tests.RLockTests): |
| locktype = staticmethod(threading.RLock) |
| |
| class EventTests(lock_tests.EventTests): |
| eventtype = staticmethod(threading.Event) |
| |
| class ConditionAsRLockTests(lock_tests.RLockTests): |
| # An Condition uses an RLock by default and exports its API. |
| locktype = staticmethod(threading.Condition) |
| |
| class ConditionTests(lock_tests.ConditionTests): |
| condtype = staticmethod(threading.Condition) |
| |
| class SemaphoreTests(lock_tests.SemaphoreTests): |
| semtype = staticmethod(threading.Semaphore) |
| |
| class BoundedSemaphoreTests(lock_tests.BoundedSemaphoreTests): |
| semtype = staticmethod(threading.BoundedSemaphore) |
| |
| |
| def test_main(): |
| test.support.run_unittest(LockTests, RLockTests, EventTests, |
| ConditionAsRLockTests, ConditionTests, |
| SemaphoreTests, BoundedSemaphoreTests, |
| ThreadTests, |
| ThreadJoinOnShutdown, |
| ThreadingExceptionTests, |
| ) |
| |
| if __name__ == "__main__": |
| test_main() |