cpython/Lib/test/test_importlib/test_locks.py
Serhiy Storchaka bedce3538c
[3.10] bpo-45229: Remove test_main in many tests (GH-28405) (GH-28455)
Instead of explicitly enumerate test classes for run_unittest()
use the unittest ability to discover tests. This also makes these
tests discoverable and runnable with unittest.

load_tests() can be used for dynamic generating tests and adding
doctests. setUpModule(), tearDownModule() and addModuleCleanup()
can be used for running code before and after all module tests.
(cherry picked from commit 40348acc18)
2021-09-19 22:36:03 +03:00

149 lines
4.4 KiB
Python

from . import util as test_util
init = test_util.import_importlib('importlib')
import sys
import threading
import unittest
import weakref
from test import support
from test.support import threading_helper
from test import lock_tests
class ModuleLockAsRLockTests:
locktype = classmethod(lambda cls: cls.LockType("some_lock"))
# _is_owned() unsupported
test__is_owned = None
# acquire(blocking=False) unsupported
test_try_acquire = None
test_try_acquire_contended = None
# `with` unsupported
test_with = None
# acquire(timeout=...) unsupported
test_timeout = None
# _release_save() unsupported
test_release_save_unacquired = None
# lock status in repr unsupported
test_repr = None
test_locked_repr = None
LOCK_TYPES = {kind: splitinit._bootstrap._ModuleLock
for kind, splitinit in init.items()}
(Frozen_ModuleLockAsRLockTests,
Source_ModuleLockAsRLockTests
) = test_util.test_both(ModuleLockAsRLockTests, lock_tests.RLockTests,
LockType=LOCK_TYPES)
class DeadlockAvoidanceTests:
def setUp(self):
try:
self.old_switchinterval = sys.getswitchinterval()
support.setswitchinterval(0.000001)
except AttributeError:
self.old_switchinterval = None
def tearDown(self):
if self.old_switchinterval is not None:
sys.setswitchinterval(self.old_switchinterval)
def run_deadlock_avoidance_test(self, create_deadlock):
NLOCKS = 10
locks = [self.LockType(str(i)) for i in range(NLOCKS)]
pairs = [(locks[i], locks[(i+1)%NLOCKS]) for i in range(NLOCKS)]
if create_deadlock:
NTHREADS = NLOCKS
else:
NTHREADS = NLOCKS - 1
barrier = threading.Barrier(NTHREADS)
results = []
def _acquire(lock):
"""Try to acquire the lock. Return True on success,
False on deadlock."""
try:
lock.acquire()
except self.DeadlockError:
return False
else:
return True
def f():
a, b = pairs.pop()
ra = _acquire(a)
barrier.wait()
rb = _acquire(b)
results.append((ra, rb))
if rb:
b.release()
if ra:
a.release()
lock_tests.Bunch(f, NTHREADS).wait_for_finished()
self.assertEqual(len(results), NTHREADS)
return results
def test_deadlock(self):
results = self.run_deadlock_avoidance_test(True)
# At least one of the threads detected a potential deadlock on its
# second acquire() call. It may be several of them, because the
# deadlock avoidance mechanism is conservative.
nb_deadlocks = results.count((True, False))
self.assertGreaterEqual(nb_deadlocks, 1)
self.assertEqual(results.count((True, True)), len(results) - nb_deadlocks)
def test_no_deadlock(self):
results = self.run_deadlock_avoidance_test(False)
self.assertEqual(results.count((True, False)), 0)
self.assertEqual(results.count((True, True)), len(results))
DEADLOCK_ERRORS = {kind: splitinit._bootstrap._DeadlockError
for kind, splitinit in init.items()}
(Frozen_DeadlockAvoidanceTests,
Source_DeadlockAvoidanceTests
) = test_util.test_both(DeadlockAvoidanceTests,
LockType=LOCK_TYPES,
DeadlockError=DEADLOCK_ERRORS)
class LifetimeTests:
@property
def bootstrap(self):
return self.init._bootstrap
def test_lock_lifetime(self):
name = "xyzzy"
self.assertNotIn(name, self.bootstrap._module_locks)
lock = self.bootstrap._get_module_lock(name)
self.assertIn(name, self.bootstrap._module_locks)
wr = weakref.ref(lock)
del lock
support.gc_collect()
self.assertNotIn(name, self.bootstrap._module_locks)
self.assertIsNone(wr())
def test_all_locks(self):
support.gc_collect()
self.assertEqual(0, len(self.bootstrap._module_locks),
self.bootstrap._module_locks)
(Frozen_LifetimeTests,
Source_LifetimeTests
) = test_util.test_both(LifetimeTests, init=init)
def setUpModule():
thread_info = threading_helper.threading_setup()
unittest.addModuleCleanup(threading_helper.threading_cleanup, *thread_info)
if __name__ == '__main__':
unittets.main()