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from test.test_importlib 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
threading_helper.requires_working_threading(module=True)
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
# _recursion_count() unsupported
test_recursion_count = None
# lock status in repr unsupported
test_repr = None
test_locked_repr = None
def tearDown(self):
for splitinit in init.values():
splitinit._bootstrap._blocking_on.clear()
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()
with lock_tests.Bunch(f, NTHREADS):
pass
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__':
unittest.main()
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