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Jython is an implementation of the high-level, dynamic, object-oriented
language Python written in 100% Pure Java, and seamlessly integrated with
the Java platform. It thus allows you to run Python on any Java platform.
"""
Various tests for synchronization primitives.
"""
import sys
import time
from thread import start_new_thread, get_ident
import threading
import unittest
from test import test_support as support
def _wait():
# A crude wait/yield function not relying on synchronization primitives.
time.sleep(0.01)
class Bunch(object):
"""
A bunch of threads.
"""
def __init__(self, f, n, wait_before_exit=False):
"""
Construct a bunch of `n` threads running the same function `f`.
If `wait_before_exit` is True, the threads won't terminate until
do_finish() is called.
"""
self.f = f
self.n = n
self.started = []
self.finished = []
self._can_exit = not wait_before_exit
def task():
tid = get_ident()
self.started.append(tid)
try:
f()
finally:
self.finished.append(tid)
while not self._can_exit:
_wait()
for i in range(n):
start_new_thread(task, ())
def wait_for_started(self):
while len(self.started) < self.n:
_wait()
def wait_for_finished(self):
while len(self.finished) < self.n:
_wait()
def do_finish(self):
self._can_exit = True
class BaseTestCase(unittest.TestCase):
def setUp(self):
self._threads = support.threading_setup()
def tearDown(self):
support.threading_cleanup(*self._threads)
support.reap_children()
class BaseLockTests(BaseTestCase):
"""
Tests for both recursive and non-recursive locks.
"""
def test_constructor(self):
lock = self.locktype()
del lock
def test_acquire_destroy(self):
lock = self.locktype()
lock.acquire()
del lock
def test_acquire_release(self):
lock = self.locktype()
lock.acquire()
lock.release()
del lock
def test_try_acquire(self):
lock = self.locktype()
self.assertTrue(lock.acquire(False))
lock.release()
def test_try_acquire_contended(self):
lock = self.locktype()
lock.acquire()
result = []
def f():
result.append(lock.acquire(False))
Bunch(f, 1).wait_for_finished()
self.assertFalse(result[0])
lock.release()
def test_acquire_contended(self):
lock = self.locktype()
lock.acquire()
N = 5
def f():
lock.acquire()
lock.release()
b = Bunch(f, N)
b.wait_for_started()
_wait()
self.assertEqual(len(b.finished), 0)
lock.release()
b.wait_for_finished()
self.assertEqual(len(b.finished), N)
def test_with(self):
lock = self.locktype()
def f():
lock.acquire()
lock.release()
def _with(err=None):
with lock:
if err is not None:
raise err
_with()
# Check the lock is unacquired
Bunch(f, 1).wait_for_finished()
self.assertRaises(TypeError, _with, TypeError)
# Check the lock is unacquired
Bunch(f, 1).wait_for_finished()
def test_thread_leak(self):
# The lock shouldn't leak a Thread instance when used from a foreign
# (non-threading) thread.
lock = self.locktype()
def f():
lock.acquire()
lock.release()
n = len(threading.enumerate())
# We run many threads in the hope that existing threads ids won't
# be recycled.
Bunch(f, 15).wait_for_finished()
self.assertEqual(n, len(threading.enumerate()))
class LockTests(BaseLockTests):
"""
Tests for non-recursive, weak locks
(which can be acquired and released from different threads).
"""
def test_reacquire(self):
# Lock needs to be released before re-acquiring.
lock = self.locktype()
phase = []
def f():
lock.acquire()
phase.append(None)
lock.acquire()
phase.append(None)
start_new_thread(f, ())
while len(phase) == 0:
_wait()
_wait()
self.assertEqual(len(phase), 1)
lock.release()
while len(phase) == 1:
_wait()
self.assertEqual(len(phase), 2)
def test_different_thread(self):
# Lock can be released from a different thread.
lock = self.locktype()
lock.acquire()
def f():
lock.release()
b = Bunch(f, 1)
b.wait_for_finished()
lock.acquire()
lock.release()
class RLockTests(BaseLockTests):
"""
Tests for recursive locks.
"""
def test_reacquire(self):
lock = self.locktype()
lock.acquire()
lock.acquire()
lock.release()
lock.acquire()
lock.release()
lock.release()
def test_release_unacquired(self):
# Cannot release an unacquired lock
lock = self.locktype()
self.assertRaises(RuntimeError, lock.release)
lock.acquire()
lock.acquire()
lock.release()
lock.acquire()
lock.release()
lock.release()
self.assertRaises(RuntimeError, lock.release)
def test_different_thread(self):
# Cannot release from a different thread
lock = self.locktype()
def f():
lock.acquire()
b = Bunch(f, 1, True)
try:
self.assertRaises(RuntimeError, lock.release)
finally:
b.do_finish()
def test__is_owned(self):
lock = self.locktype()
self.assertFalse(lock._is_owned())
lock.acquire()
self.assertTrue(lock._is_owned())
lock.acquire()
self.assertTrue(lock._is_owned())
result = []
def f():
result.append(lock._is_owned())
Bunch(f, 1).wait_for_finished()
self.assertFalse(result[0])
lock.release()
self.assertTrue(lock._is_owned())
lock.release()
self.assertFalse(lock._is_owned())
class EventTests(BaseTestCase):
"""
Tests for Event objects.
"""
def test_is_set(self):
evt = self.eventtype()
self.assertFalse(evt.is_set())
evt.set()
self.assertTrue(evt.is_set())
evt.set()
self.assertTrue(evt.is_set())
evt.clear()
self.assertFalse(evt.is_set())
evt.clear()
self.assertFalse(evt.is_set())
def _check_notify(self, evt):
# All threads get notified
N = 5
results1 = []
results2 = []
def f():
results1.append(evt.wait())
results2.append(evt.wait())
b = Bunch(f, N)
b.wait_for_started()
_wait()
self.assertEqual(len(results1), 0)
evt.set()
b.wait_for_finished()
self.assertEqual(results1, [True] * N)
self.assertEqual(results2, [True] * N)
def test_notify(self):
evt = self.eventtype()
self._check_notify(evt)
# Another time, after an explicit clear()
evt.set()
evt.clear()
self._check_notify(evt)
def test_timeout(self):
evt = self.eventtype()
results1 = []
results2 = []
N = 5
def f():
results1.append(evt.wait(0.0))
t1 = time.time()
r = evt.wait(0.2)
t2 = time.time()
results2.append((r, t2 - t1))
Bunch(f, N).wait_for_finished()
self.assertEqual(results1, [False] * N)
for r, dt in results2:
self.assertFalse(r)
# Fudge factor for running on the JVM - actual waits on
# some OS platforms might be like this example,
# 0.199999809265, slightly less than 0.2 seconds. To avoid
# unnecessary flakiness in testing, make epsilon
# relatively large:
epsilon = 0.01
self.assertTrue(dt >= 0.2 - epsilon, dt)
# The event is set
results1 = []
results2 = []
evt.set()
Bunch(f, N).wait_for_finished()
self.assertEqual(results1, [True] * N)
for r, dt in results2:
self.assertTrue(r)
class ConditionTests(BaseTestCase):
"""
Tests for condition variables.
"""
def test_acquire(self):
cond = self.condtype()
# Be default we have an RLock: the condition can be acquired multiple
# times.
cond.acquire()
cond.acquire()
cond.release()
cond.release()
lock = threading.Lock()
cond = self.condtype(lock)
cond.acquire()
self.assertFalse(lock.acquire(False))
cond.release()
self.assertTrue(lock.acquire(False))
self.assertFalse(cond.acquire(False))
lock.release()
with cond:
self.assertFalse(lock.acquire(False))
def test_unacquired_wait(self):
cond = self.condtype()
self.assertRaises(RuntimeError, cond.wait)
def test_unacquired_notify(self):
cond = self.condtype()
self.assertRaises(RuntimeError, cond.notify)
def _check_notify(self, cond):
N = 5
results1 = []
results2 = []
phase_num = 0
def f():
cond.acquire()
cond.wait()
cond.release()
results1.append(phase_num)
cond.acquire()
cond.wait()
cond.release()
results2.append(phase_num)
b = Bunch(f, N)
b.wait_for_started()
_wait()
self.assertEqual(results1, [])
# Notify 3 threads at first
cond.acquire()
cond.notify(3)
_wait()
phase_num = 1
cond.release()
while len(results1) < 3:
_wait()
self.assertEqual(results1, [1] * 3)
self.assertEqual(results2, [])
# Notify 5 threads: they might be in their first or second wait
cond.acquire()
cond.notify(5)
_wait()
phase_num = 2
cond.release()
while len(results1) + len(results2) < 8:
_wait()
self.assertEqual(results1, [1] * 3 + [2] * 2)
self.assertEqual(results2, [2] * 3)
# Notify all threads: they are all in their second wait
cond.acquire()
cond.notify_all()
_wait()
phase_num = 3
cond.release()
while len(results2) < 5:
_wait()
self.assertEqual(results1, [1] * 3 + [2] * 2)
self.assertEqual(results2, [2] * 3 + [3] * 2)
b.wait_for_finished()
def test_notify(self):
cond = self.condtype()
self._check_notify(cond)
# A second time, to check internal state is still ok.
self._check_notify(cond)
def test_timeout(self):
cond = self.condtype()
results = []
N = 5
def f():
cond.acquire()
t1 = time.time()
cond.wait(0.2)
t2 = time.time()
cond.release()
results.append(t2 - t1)
Bunch(f, N).wait_for_finished()
self.assertEqual(len(results), 5)
for dt in results:
self.assertTrue(dt >= 0.2, dt)
class BaseSemaphoreTests(BaseTestCase):
"""
Common tests for {bounded, unbounded} semaphore objects.
"""
def test_constructor(self):
self.assertRaises(ValueError, self.semtype, value = -1)
self.assertRaises(ValueError, self.semtype, value = -sys.maxint)
def test_acquire(self):
sem = self.semtype(1)
sem.acquire()
sem.release()
sem = self.semtype(2)
sem.acquire()
sem.acquire()
sem.release()
sem.release()
def test_acquire_destroy(self):
sem = self.semtype()
sem.acquire()
del sem
def test_acquire_contended(self):
sem = self.semtype(7)
sem.acquire()
N = 10
results1 = []
results2 = []
phase_num = 0
def f():
sem.acquire()
results1.append(phase_num)
sem.acquire()
results2.append(phase_num)
b = Bunch(f, 10)
b.wait_for_started()
while len(results1) + len(results2) < 6:
_wait()
self.assertEqual(results1 + results2, [0] * 6)
phase_num = 1
for i in range(7):
sem.release()
while len(results1) + len(results2) < 13:
_wait()
self.assertEqual(sorted(results1 + results2), [0] * 6 + [1] * 7)
phase_num = 2
for i in range(6):
sem.release()
while len(results1) + len(results2) < 19:
_wait()
self.assertEqual(sorted(results1 + results2), [0] * 6 + [1] * 7 + [2] * 6)
# The semaphore is still locked
self.assertFalse(sem.acquire(False))
# Final release, to let the last thread finish
sem.release()
b.wait_for_finished()
def test_try_acquire(self):
sem = self.semtype(2)
self.assertTrue(sem.acquire(False))
self.assertTrue(sem.acquire(False))
self.assertFalse(sem.acquire(False))
sem.release()
self.assertTrue(sem.acquire(False))
def test_try_acquire_contended(self):
sem = self.semtype(4)
sem.acquire()
results = []
def f():
results.append(sem.acquire(False))
results.append(sem.acquire(False))
Bunch(f, 5).wait_for_finished()
# There can be a thread switch between acquiring the semaphore and
# appending the result, therefore results will not necessarily be
# ordered.
self.assertEqual(sorted(results), [False] * 7 + [True] * 3 )
def test_default_value(self):
# The default initial value is 1.
sem = self.semtype()
sem.acquire()
def f():
sem.acquire()
sem.release()
b = Bunch(f, 1)
b.wait_for_started()
_wait()
self.assertFalse(b.finished)
sem.release()
b.wait_for_finished()
def test_with(self):
sem = self.semtype(2)
def _with(err=None):
with sem:
self.assertTrue(sem.acquire(False))
sem.release()
with sem:
self.assertFalse(sem.acquire(False))
if err:
raise err
_with()
self.assertTrue(sem.acquire(False))
sem.release()
self.assertRaises(TypeError, _with, TypeError)
self.assertTrue(sem.acquire(False))
sem.release()
class SemaphoreTests(BaseSemaphoreTests):
"""
Tests for unbounded semaphores.
"""
def test_release_unacquired(self):
# Unbounded releases are allowed and increment the semaphore's value
sem = self.semtype(1)
sem.release()
sem.acquire()
sem.acquire()
sem.release()
class BoundedSemaphoreTests(BaseSemaphoreTests):
"""
Tests for bounded semaphores.
"""
def test_release_unacquired(self):
# Cannot go past the initial value
sem = self.semtype()
self.assertRaises(ValueError, sem.release)
sem.acquire()
sem.release()
self.assertRaises(ValueError, sem.release)