def test_context_manager_timeout(self):
sem = locks.Semaphore()
with (yield sem.acquire(timedelta(seconds=0.01))):
pass
# Semaphore was released and can be acquired again.
self.assertTrue(sem.acquire().done())
def test_context_manager(self):
sem = locks.Semaphore()
with (yield sem.acquire()) as yielded:
self.assertTrue(yielded is None)
# Semaphore was released and can be acquired again.
self.assertTrue(sem.acquire().done())
def test_context_manager_timeout_error(self):
sem = locks.Semaphore(value=0)
with self.assertRaises(gen.TimeoutError):
with (yield sem.acquire(timedelta(seconds=0.01))):
pass
# Counter is still 0.
self.assertFalse(sem.acquire().done())
def test_context_manager_exception(self):
sem = locks.Semaphore()
with self.assertRaises(ZeroDivisionError):
with (yield sem.acquire()):
1 / 0
# Semaphore was released and can be acquired again.
self.assertTrue(sem.acquire().done())
def test_acquire_timeout_preempted(self):
sem = locks.Semaphore(1)
yield sem.acquire()
# This fires before the wait times out.
self.io_loop.call_later(0.01, sem.release)
acquire = sem.acquire(timedelta(seconds=0.02))
yield gen.sleep(0.03)
yield acquire # No TimeoutError.
def test_repr(self):
sem = locks.Semaphore()
self.assertIn('Semaphore', repr(sem))
self.assertIn('unlocked,value:1', repr(sem))
sem.acquire()
self.assertIn('locked', repr(sem))
self.assertNotIn('waiters', repr(sem))
sem.acquire()
self.assertIn('waiters', repr(sem))
def test_release_unacquired(self):
# Unbounded releases are allowed, and increment the semaphore's value.
sem = locks.Semaphore()
sem.release()
sem.release()
# Now the counter is 3. We can acquire three times before blocking.
self.assertTrue(sem.acquire().done())
self.assertTrue(sem.acquire().done())
self.assertTrue(sem.acquire().done())
self.assertFalse(sem.acquire().done())
def test_context_manager_async_await(self):
# Repeat the above test using 'async with'.
sem = locks.Semaphore()
namespace = exec_test(
globals(), locals(), """
async def f():
async with sem as yielded:
self.assertTrue(yielded is None)
""")
yield namespace['f']()
# Semaphore was released and can be acquired again.
self.assertTrue(sem.acquire().done())
def test_acquire_timeout(self):
sem = locks.Semaphore(2)
yield sem.acquire()
yield sem.acquire()
acquire = sem.acquire(timedelta(seconds=0.01))
self.io_loop.call_later(0.02, sem.release) # Too late.
yield gen.sleep(0.3)
with self.assertRaises(gen.TimeoutError):
yield acquire
sem.acquire()
f = sem.acquire()
self.assertFalse(f.done())
sem.release()
self.assertTrue(f.done())
def test_context_manager_contended(self):
sem = locks.Semaphore()
history = []
@gen.coroutine
def f(index):
with (yield sem.acquire()):
history.append('acquired %d' % index)
yield gen.sleep(0.01)
history.append('release %d' % index)
yield [f(i) for i in range(2)]
expected_history = []
for i in range(2):
expected_history.extend(['acquired %d' % i, 'release %d' % i])
self.assertEqual(expected_history, history)
def test_acquire(self):
sem = locks.Semaphore()
f0 = sem.acquire()
self.assertTrue(f0.done())
# Wait for release().
f1 = sem.acquire()
self.assertFalse(f1.done())
f2 = sem.acquire()
sem.release()
self.assertTrue(f1.done())
self.assertFalse(f2.done())
sem.release()
self.assertTrue(f2.done())
sem.release()
# Now acquire() is instant.
self.assertTrue(sem.acquire().done())
self.assertEqual(0, len(sem._waiters))
def test_garbage_collection(self):
# Test that timed-out waiters are occasionally cleaned from the queue.
sem = locks.Semaphore(value=0)
futures = [sem.acquire(timedelta(seconds=0.01)) for _ in range(101)]
future = sem.acquire()
self.assertEqual(102, len(sem._waiters))
# Let first 101 waiters time out, triggering a collection.
yield gen.sleep(0.02)
self.assertEqual(1, len(sem._waiters))
# Final waiter is still active.
self.assertFalse(future.done())
sem.release()
self.assertTrue(future.done())
# Prevent "Future exception was never retrieved" messages.
for future in futures:
self.assertRaises(TimeoutError, future.result)
def test_context_manager_misuse(self):
# Ensure we catch a "with sem", which should be
# "with (yield sem.acquire())".
with self.assertRaises(RuntimeError):
with locks.Semaphore():
pass
def test_yield_sem(self):
# Ensure we catch a "with (yield sem)", which should be
# "with (yield sem.acquire())".
with self.assertRaises(gen.BadYieldError):
with (yield locks.Semaphore()):
pass
