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Diffstat (limited to 'lib/python2.7/test/test_threading.py')
| -rw-r--r-- | lib/python2.7/test/test_threading.py | 778 |
1 files changed, 778 insertions, 0 deletions
diff --git a/lib/python2.7/test/test_threading.py b/lib/python2.7/test/test_threading.py new file mode 100644 index 0000000..ef04cd3 --- /dev/null +++ b/lib/python2.7/test/test_threading.py @@ -0,0 +1,778 @@ +# Very rudimentary test of threading module + +import test.test_support +from test.test_support import verbose +from test.script_helper import assert_python_ok + +import random +import re +import sys +thread = test.test_support.import_module('thread') +threading = test.test_support.import_module('threading') +import time +import unittest +import weakref +import os +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 BaseTestCase(unittest.TestCase): + def setUp(self): + self._threads = test.test_support.threading_setup() + + def tearDown(self): + test.test_support.threading_cleanup(*self._threads) + test.test_support.reap_children() + + +class ThreadTests(BaseTestCase): + + # 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.assertIn(tid, threading._active) + self.assertIsInstance(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) + + # First check it works when setting the exception from the same thread. + tid = thread.get_ident() + + try: + result = set_async_exc(ctypes.c_long(tid), exception) + # The exception is async, so we might have to keep the VM busy until + # it notices. + while True: + pass + except AsyncExc: + pass + else: + # This code is unreachable but it reflects the intent. If we wanted + # to be smarter the above loop wouldn't be infinite. + self.fail("AsyncExc not raised") + try: + self.assertEqual(result, 1) # one thread state modified + except UnboundLocalError: + # The exception was raised too quickly for us to get the result. + pass + + # `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 thread.error() + _start_new_thread = threading._start_new_thread + threading._start_new_thread = fail_new_thread + try: + t = threading.Thread(target=lambda: None) + self.assertRaises(thread.error, 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) + self.addCleanup(p.stdout.close) + self.addCleanup(p.stderr.close) + stdout, stderr = p.communicate() + rc = p.returncode + self.assertFalse(rc == 2, "interpreted was blocked") + self.assertTrue(rc == 0, + "Unexpected error: " + repr(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) + self.addCleanup(p.stdout.close) + self.addCleanup(p.stderr.close) + stdout, stderr = p.communicate() + self.assertEqual(stdout.strip(), + "Woke up, sleep function is: <built-in function sleep>") + stderr = re.sub(r"^\[\d+ refs\]", "", stderr, re.MULTILINE).strip() + self.assertEqual(stderr, "") + + 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 xrange(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.assertNotIn(t, 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()))) + + @unittest.skipUnless(hasattr(os, 'fork'), 'test needs fork()') + def test_dummy_thread_after_fork(self): + # Issue #14308: a dummy thread in the active list doesn't mess up + # the after-fork mechanism. + code = """if 1: + import thread, threading, os, time + + def background_thread(evt): + # Creates and registers the _DummyThread instance + threading.current_thread() + evt.set() + time.sleep(10) + + evt = threading.Event() + thread.start_new_thread(background_thread, (evt,)) + evt.wait() + assert threading.active_count() == 2, threading.active_count() + if os.fork() == 0: + assert threading.active_count() == 1, threading.active_count() + os._exit(0) + else: + os.wait() + """ + _, out, err = assert_python_ok("-c", code) + self.assertEqual(out, '') + self.assertEqual(err, '') + + +class ThreadJoinOnShutdown(BaseTestCase): + + # Between fork() and exec(), only async-safe functions are allowed (issues + # #12316 and #11870), and fork() from a worker thread is known to trigger + # problems with some operating systems (issue #3863): skip problematic tests + # on platforms known to behave badly. + platforms_to_skip = ('freebsd4', 'freebsd5', 'freebsd6', 'netbsd5', + 'os2emx') + + 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 + + p = subprocess.Popen([sys.executable, "-c", script], stdout=subprocess.PIPE) + rc = p.wait() + data = p.stdout.read().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) + + + @unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()") + @unittest.skipIf(sys.platform in platforms_to_skip, "due to known OS bug") + def test_2_join_in_forked_process(self): + # Like the test above, but from a forked interpreter + 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) + + @unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()") + @unittest.skipIf(sys.platform in platforms_to_skip, "due to known OS bug") + 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. + 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()") + @unittest.skipIf(sys.platform in platforms_to_skip, "due to known OS bug") + 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. + + # 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()") + @unittest.skipIf(sys.platform in platforms_to_skip, "due to known OS bug") + 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. + + 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) + + @unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()") + @unittest.skipIf(sys.platform in platforms_to_skip, "due to known OS bug") + def test_reinit_tls_after_fork(self): + # Issue #13817: fork() would deadlock in a multithreaded program with + # the ad-hoc TLS implementation. + + def do_fork_and_wait(): + # just fork a child process and wait it + pid = os.fork() + if pid > 0: + os.waitpid(pid, 0) + else: + os._exit(0) + + # start a bunch of threads that will fork() child processes + threads = [] + for i in range(16): + t = threading.Thread(target=do_fork_and_wait) + threads.append(t) + t.start() + + for t in threads: + t.join() + + +class ThreadingExceptionTests(BaseTestCase): + # 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) + + @unittest.skipUnless(sys.platform == 'darwin', 'test macosx problem') + def test_recursion_limit(self): + # Issue 9670 + # test that excessive recursion within a non-main thread causes + # an exception rather than crashing the interpreter on platforms + # like Mac OS X or FreeBSD which have small default stack sizes + # for threads + script = """if True: + import threading + + def recurse(): + return recurse() + + def outer(): + try: + recurse() + except RuntimeError: + pass + + w = threading.Thread(target=outer) + w.start() + w.join() + print('end of main thread') + """ + expected_output = "end of main thread\n" + p = subprocess.Popen([sys.executable, "-c", script], + stdout=subprocess.PIPE) + stdout, stderr = p.communicate() + data = stdout.decode().replace('\r', '') + self.assertEqual(p.returncode, 0, "Unexpected error") + self.assertEqual(data, expected_output) + +def test_main(): + test.test_support.run_unittest(LockTests, RLockTests, EventTests, + ConditionAsRLockTests, ConditionTests, + SemaphoreTests, BoundedSemaphoreTests, + ThreadTests, + ThreadJoinOnShutdown, + ThreadingExceptionTests, + ) + +if __name__ == "__main__": + test_main() |