"""Tests for locks.py"""
import unittest
from unittest import mock
import re
import asyncio
import collections
STR_RGX_REPR = (
r'^<(?P<class>.*?) object at (?P<address>.*?)'
r'\[(?P<extras>'
r'(set|unset|locked|unlocked|filling|draining|resetting|broken)'
r'(, value:\d)?'
r'(, waiters:\d+)?'
r'(, waiters:\d+\/\d+)?' # barrier
r')\]>\Z'
)
RGX_REPR = re.compile(STR_RGX_REPR)
def tearDownModule():
asyncio.set_event_loop_policy(None)
class LockTests(unittest.IsolatedAsyncioTestCase):
async def test_repr(self):
lock = asyncio.Lock()
self.assertTrue(repr(lock).endswith('[unlocked]>'))
self.assertTrue(RGX_REPR.match(repr(lock)))
await lock.acquire()
self.assertTrue(repr(lock).endswith('[locked]>'))
self.assertTrue(RGX_REPR.match(repr(lock)))
async def test_lock(self):
lock = asyncio.Lock()
with self.assertRaisesRegex(
TypeError,
"'Lock' object can't be awaited"
):
await lock
self.assertFalse(lock.locked())
async def test_lock_doesnt_accept_loop_parameter(self):
primitives_cls = [
asyncio.Lock,
asyncio.Condition,
asyncio.Event,
asyncio.Semaphore,
asyncio.BoundedSemaphore,
]
loop = asyncio.get_running_loop()
for cls in primitives_cls:
with self.assertRaisesRegex(
TypeError,
rf"{cls.__name__}\.__init__\(\) got an unexpected "
rf"keyword argument 'loop'"
):
cls(loop=loop)
async def test_lock_by_with_statement(self):
primitives = [
asyncio.Lock(),
asyncio.Condition(),
asyncio.Semaphore(),
asyncio.BoundedSemaphore(),
]
for lock in primitives:
await asyncio.sleep(0.01)
self.assertFalse(lock.locked())
with self.assertRaisesRegex(
TypeError,
r"'\w+' object can't be awaited"
):
with await lock:
pass
self.assertFalse(lock.locked())
async def test_acquire(self):
lock = asyncio.Lock()
result = []
self.assertTrue(await lock.acquire())
async def c1(result):
if await lock.acquire():
result.append(1)
return True
async def c2(result):
if await lock.acquire():
result.append(2)
return True
async def c3(result):
if await lock.acquire():
result.append(3)
return True
t1 = asyncio.create_task(c1(result))
t2 = asyncio.create_task(c2(result))
await asyncio.sleep(0)
self.assertEqual([], result)
lock.release()
await asyncio.sleep(0)
self.assertEqual([1], result)
await asyncio.sleep(0)
self.assertEqual([1], result)
t3 = asyncio.create_task(c3(result))
lock.release()
await asyncio.sleep(0)
self.assertEqual([1, 2], result)
lock.release()
await asyncio.sleep(0)
self.assertEqual([1, 2, 3], result)
self.assertTrue(t1.done())
self.assertTrue(t1.result())
self.assertTrue(t2.done())
self.assertTrue(t2.result())
self.assertTrue(t3.done())
self.assertTrue(t3.result())
async def test_acquire_cancel(self):
lock = asyncio.Lock()
self.assertTrue(await lock.acquire())
task = asyncio.create_task(lock.acquire())
asyncio.get_running_loop().call_soon(task.cancel)
with self.assertRaises(asyncio.CancelledError):
await task
self.assertFalse(lock._waiters)
async def test_cancel_race(self):
# Several tasks:
# - A acquires the lock
# - B is blocked in acquire()
# - C is blocked in acquire()
#
# Now, concurrently:
# - B is cancelled
# - A releases the lock
#
# If B's waiter is marked cancelled but not yet removed from
# _waiters, A's release() call will crash when trying to set
# B's waiter; instead, it should move on to C's waiter.
# Setup: A has the lock, b and c are waiting.
lock = asyncio.Lock()
async def lockit(name, blocker):
await lock.acquire()
try:
if blocker is not None:
await blocker
finally:
lock.release()
fa = asyncio.get_running_loop().create_future()
ta = asyncio.create_task(lockit('A', fa))
await asyncio.sleep(0)
self.assertTrue(lock.locked())
tb = asyncio.create_task(lockit('B', None))
await asyncio.sleep(0)
self.assertEqual(len(lock._waiters), 1)
tc = asyncio.create_task(lockit('C', None))
await asyncio.sleep(0)
self.assertEqual(len(lock._waiters), 2)
# Create the race and check.
# Without the fix this failed at the last assert.
fa.set_result(None)
tb.cancel()
self.assertTrue(lock._waiters[0].cancelled())
await asyncio.sleep(0)
self.assertFalse(lock.locked())
self.assertTrue(ta.done())
self.assertTrue(tb.cancelled())
await tc
async def test_cancel_release_race(self):
# Issue 32734
# Acquire 4 locks, cancel second, release first
# and 2 locks are taken at once.
loop = asyncio.get_running_loop()
lock = asyncio.Lock()
lock_count = 0
call_count = 0
async def lockit():
nonlocal lock_count
nonlocal call_count
call_count += 1
await lock.acquire()
lock_count += 1
def trigger():
t1.cancel()
lock.release()
await lock.acquire()
t1 = asyncio.create_task(lockit())
t2 = asyncio.create_task(lockit())
t3 = asyncio.create_task(lockit())
# Start scheduled tasks
await asyncio.sleep(0)
loop.call_soon(trigger)
with self.assertRaises(asyncio.CancelledError):
# Wait for cancellation
await t1
# Make sure only one lock was taken
self.assertEqual(lock_count, 1)
# While 3 calls were made to lockit()
self.assertEqual(call_count, 3)
self.assertTrue(t1.cancelled() and t2.done())
# Cleanup the task that is stuck on acquire.
t3.cancel()
await asyncio.sleep(0)
self.assertTrue(t3.cancelled())
async def test_finished_waiter_cancelled(self):
lock = asyncio.Lock()
await lock.acquire()
self.assertTrue(lock.locked())
tb = asyncio.create_task(lock.acquire())
await asyncio.sleep(0)
self.assertEqual(len(lock._waiters), 1)
# Create a second waiter, wake up the first, and cancel it.
# Without the fix, the second was not woken up.
tc = asyncio.create_task(lock.acquire())
tb.cancel()
lock.release()
await asyncio.sleep(0)
self.assertTrue(lock.locked())
self.assertTrue(tb.cancelled())
# Cleanup
await tc
async def test_release_not_acquired(self):
lock = asyncio.Lock()
self.assertRaises(RuntimeError, lock.release)
async def test_release_no_waiters(self):
lock = asyncio.Lock()
await lock.acquire()
self.assertTrue(lock.locked())
lock.release()
self.assertFalse(lock.locked())
async def test_context_manager(self):
lock = asyncio.Lock()
self.assertFalse(lock.locked())
async with lock:
self.assertTrue(lock.locked())
self.assertFalse(lock.locked())
class EventTests(unittest.IsolatedAsyncioTestCase):
def test_repr(self):
ev = asyncio.Event()
self.assertTrue(repr(ev).endswith('[unset]>'))
match = RGX_REPR.match(repr(ev))
self.assertEqual(match.group('extras'), 'unset')
ev.set()
self.assertTrue(repr(ev).endswith('[set]>'))
self.assertTrue(RGX_REPR.match(repr(ev)))
ev._waiters.append(mock.Mock())
self.assertTrue('waiters:1' in repr(ev))
self.assertTrue(RGX_REPR.match(repr(ev)))
async def test_wait(self):
ev = asyncio.Event()
self.assertFalse(ev.is_set())
result = []
async def c1(result):
if await ev.wait():
result.append(1)
async def c2(result):
if await ev.wait():
result.append(2)
async def c3(result):
if await ev.wait():
result.append(3)
t1 = asyncio.create_task(c1(result))
t2 = asyncio.create_task(c2(result))
await asyncio.sleep(0)
self.assertEqual([], result)
t3 = asyncio.create_task(c3(result))
ev.set()
await asyncio.sleep(0)
self.assertEqual([3, 1, 2], result)
self.assertTrue(t1.done())
self.assertIsNone(t1.result())
self.assertTrue(t2.done())
self.assertIsNone(t2.result())
self.assertTrue(t3.done())
self.assertIsNone(t3.result())
async def test_wait_on_set(self):
ev = asyncio.Event()
ev.set()
res = await ev.wait()
self.assertTrue(res)
async def test_wait_cancel(self):
ev = asyncio.Event()
wait = asyncio.create_task(ev.wait())
asyncio.get_running_loop().call_soon(wait.cancel)
with self.assertRaises(asyncio.CancelledError):
await wait
self.assertFalse(ev._waiters)
async def test_clear(self):
ev = asyncio.Event()
self.assertFalse(ev.is_set())
ev.set()
self.assertTrue(ev.is_set())
ev.clear()
self.assertFalse(ev.is_set())
async def test_clear_with_waiters(self):
ev = asyncio.Event()
result = []
async def c1(result):
if await ev.wait():
result.append(1)
return True
t = asyncio.create_task(c1(result))
await asyncio.sleep(0)
self.assertEqual([], result)
ev.set()
ev.clear()
self.assertFalse(ev.is_set())
ev.set()
ev.set()
self.assertEqual(1, len(ev._waiters))
await asyncio.sleep(0)
self.assertEqual([1], result)
self.assertEqual(0, len(ev._waiters))
self.assertTrue(t.done())
self.assertTrue(t.result())
class ConditionTests(unittest.IsolatedAsyncioTestCase):
async def test_wait(self):
cond = asyncio.Condition()
result = []
async def c1(result):
await cond.acquire()
if await cond.wait():
result.append(1)
return True
async def c2(result):
await cond.acquire()
if await cond.wait():
result.append(2)
return True
async def c3(result):
await cond.acquire()
if await cond.wait():
result.append(3)
return True
t1 = asyncio.create_task(c1(result))
t2 = asyncio.create_task(c2(result))
t3 = asyncio.create_task(c3(result))
await asyncio.sleep(0)
self.assertEqual([], result)
self.assertFalse(cond.locked())
self.assertTrue(await cond.acquire())
cond.notify()
await asyncio.sleep(0)
self.assertEqual([], result)
self.assertTrue(cond.locked())
cond.release()
await asyncio.sleep(0)
self.assertEqual([1], result)
self.assertTrue(cond.locked())
cond.notify(2)
await asyncio.sleep(0)
self.assertEqual([1], result)
self.assertTrue(cond.locked())
cond.release()
await asyncio.sleep(0)
self.assertEqual([1, 2], result)
self.assertTrue(cond.locked())
cond.release()
await asyncio.sleep(0)
self.assertEqual([1, 2, 3], result)
self.assertTrue(cond.locked())
self.assertTrue(t1.done())
self.assertTrue(t1.result())
self.assertTrue(t2.done())
self.assertTrue(t2.result())
self.assertTrue(t3.done())
self.assertTrue(t3.result())
async def test_wait_cancel(self):
cond = asyncio.Condition()
await cond.acquire()
wait = asyncio.create_task(cond.wait())
asyncio.get_running_loop().call_soon(wait.cancel)
with self.assertRaises(asyncio.CancelledError):
await wait
self.assertFalse(cond._waiters)
self.assertTrue(cond.locked())
async def test_wait_cancel_contested(self):
cond = asyncio.Condition()
await cond.acquire()
self.assertTrue(cond.locked())
wait_task = asyncio.create_task(cond.wait())
await asyncio.sleep(0)
self.assertFalse(cond.locked())
# Notify, but contest the lock before cancelling
await cond.acquire()
self.assertTrue(cond.locked())
cond.notify()
asyncio.get_running_loop().call_soon(wait_task.cancel)
asyncio.get_running_loop().call_soon(cond.release)
try:
await wait_task
except asyncio.CancelledError:
# Should not happen, since no cancellation points
pass
self.assertTrue(cond.locked())
async def test_wait_cancel_after_notify(self):
# See bpo-32841
waited = False
cond = asyncio.Condition()
async def wait_on_cond():
nonlocal waited
async with cond:
waited = True # Make sure this area was reached
await cond.wait()
waiter = asyncio.create_task(wait_on_cond())
await asyncio.sleep(0) # Start waiting
await cond.acquire()
cond.notify()
await asyncio.sleep(0) # Get to acquire()
waiter.cancel()
await asyncio.sleep(0) # Activate cancellation
cond.release()
await asyncio.sleep(0) # Cancellation should occur
self.assertTrue(waiter.cancelled())
self.assertTrue(waited)
async def test_wait_unacquired(self):
cond = asyncio.Condition()
with self.assertRaises(RuntimeError):
await cond.wait()
async def test_wait_for(self):
cond = asyncio.Condition()
presult = False
def predicate():
return presult
result = []
async def c1(result):
await cond.acquire()
if await cond.wait_for(predicate):
result.append(1)
cond.release()
return True
t = asyncio.create_task(c1(result))
await asyncio.sleep(0)
self.assertEqual([], result)
await cond.acquire()
cond.notify()
cond.release()
await asyncio.sleep(0)
self.assertEqual([], result)
presult = True
await cond.acquire()
cond.notify()
cond.release()
await asyncio.sleep(0)
self.assertEqual([1], result)
self.assertTrue(t.done())
self.assertTrue(t.result())
async def test_wait_for_unacquired(self):
cond = asyncio.Condition()
# predicate can return true immediately
res = await cond.wait_for(lambda: [1, 2, 3])
self.assertEqual([1, 2, 3], res)
with self.assertRaises(RuntimeError):
await cond.wait_for(lambda: False)
async def test_notify(self):
cond = asyncio.Condition()
result = []
async def c1(result):
await cond.acquire()
if await cond.wait():
result.append(1)
cond.release()
return True
async def c2(result):
await cond.acquire()
if await cond.wait():
result.append(2)
cond.release()
return True
async def c3(result):
await cond.acquire()
if await cond.wait():
result.append(3)
cond.release()
return True
t1 = asyncio.create_task(c1(result))
t2 = asyncio.create_task(c2(result))
t3 = asyncio.create_task(c3(result))
await asyncio.sleep(0)
self.assertEqual([], result)
await cond.acquire()
cond.notify(1)
cond.release()
await asyncio.sleep(0)
self.assertEqual([1], result)
await cond.acquire()
cond.notify(1)
cond.notify(2048)
cond.release()
await asyncio.sleep(0)
self.assertEqual([1, 2, 3], result)
self.assertTrue(t1.done())
self.assertTrue(t1.result())
self.assertTrue(t2.done())
self.assertTrue(t2.result())
self.assertTrue(t3.done())
self.assertTrue(t3.result())
async def test_notify_all(self):
cond = asyncio.Condition()
result = []
async def c1(result):
await cond.acquire()
if await cond.wait():
result.append(1)
cond.release()
return True
async def c2(result):
await cond.acquire()
if await cond.wait():
result.append(2)
cond.release()
return True
t1 = asyncio.create_task(c1(result))
t2 = asyncio.create_task(c2(result))
await asyncio.sleep(0)
self.assertEqual([], result)
await cond.acquire()
cond.notify_all()
cond.release()
await asyncio.sleep(0)
self.assertEqual([1, 2], result)
self.assertTrue(t1.done())
self.assertTrue(t1.result())
self.assertTrue(t2.done())
self.assertTrue(t2.result())
def test_notify_unacquired(self):
cond = asyncio.Condition()
self.assertRaises(RuntimeError, cond.notify)
def test_notify_all_unacquired(self):
cond = asyncio.Condition()
self.assertRaises(RuntimeError, cond.notify_all)
async def test_repr(self):
cond = asyncio.Condition()
self.assertTrue('unlocked' in repr(cond))
self.assertTrue(RGX_REPR.match(repr(cond)))
await cond.acquire()
self.assertTrue('locked' in repr(cond))
cond._waiters.append(mock.Mock())
self.assertTrue('waiters:1' in repr(cond))
self.assertTrue(RGX_REPR.match(repr(cond)))
cond._waiters.append(mock.Mock())
self.assertTrue('waiters:2' in repr(cond))
self.assertTrue(RGX_REPR.match(repr(cond)))
async def test_context_manager(self):
cond = asyncio.Condition()
self.assertFalse(cond.locked())
async with cond:
self.assertTrue(cond.locked())
self.assertFalse(cond.locked())
async def test_explicit_lock(self):
async def f(lock=None, cond=None):
if lock is None:
lock = asyncio.Lock()
if cond is None:
cond = asyncio.Condition(lock)
self.assertIs(cond._lock, lock)
self.assertFalse(lock.locked())
self.assertFalse(cond.locked())
async with cond:
self.assertTrue(lock.locked())
self.assertTrue(cond.locked())
self.assertFalse(lock.locked())
self.assertFalse(cond.locked())
async with lock:
self.assertTrue(lock.locked())
self.assertTrue(cond.locked())
self.assertFalse(lock.locked())
self.assertFalse(cond.locked())
# All should work in the same way.
await f()
await f(asyncio.Lock())
lock = asyncio.Lock()
await f(lock, asyncio.Condition(lock))
async def test_ambiguous_loops(self):
loop = asyncio.new_event_loop()
self.addCleanup(loop.close)
async def wrong_loop_in_lock():
with self.assertRaises(TypeError):
asyncio.Lock(loop=loop) # actively disallowed since 3.10
lock = asyncio.Lock()
lock._loop = loop # use private API for testing
async with lock:
# acquired immediately via the fast-path
# without interaction with any event loop.
cond = asyncio.Condition(lock)
# cond.acquire() will trigger waiting on the lock
# and it will discover the event loop mismatch.
with self.assertRaisesRegex(
RuntimeError,
"is bound to a different event loop",
):
await cond.acquire()
async def wrong_loop_in_cond():
# Same analogy here with the condition's loop.
lock = asyncio.Lock()
async with lock:
with self.assertRaises(TypeError):
asyncio.Condition(lock, loop=loop)
cond = asyncio.Condition(lock)
cond._loop = loop
with self.assertRaisesRegex(
RuntimeError,
"is bound to a different event loop",
):
await cond.wait()
await wrong_loop_in_lock()
await wrong_loop_in_cond()
async def test_timeout_in_block(self):
condition = asyncio.Condition()
async with condition:
with self.assertRaises(asyncio.TimeoutError):
await asyncio.wait_for(condition.wait(), timeout=0.5)
async def test_cancelled_error_wakeup(self):
# Test that a cancelled error, received when awaiting wakeup,
# will be re-raised un-modified.
wake = False
raised = None
cond = asyncio.Condition()
async def func():
nonlocal raised
async with cond:
with self.assertRaises(asyncio.CancelledError) as err:
await cond.wait_for(lambda: wake)
raised = err.exception
raise raised
task = asyncio.create_task(func())
await asyncio.sleep(0)
# Task is waiting on the condition, cancel it there.
task.cancel(msg="foo")
with self.assertRaises(asyncio.CancelledError) as err:
await task
self.assertEqual(err.exception.args, ("foo",))
# We should have got the _same_ exception instance as the one
# originally raised.
self.assertIs(err.exception, raised)
async def test_cancelled_error_re_aquire(self):
# Test that a cancelled error, received when re-aquiring lock,
# will be re-raised un-modified.
wake = False
raised = None
cond = asyncio.Condition()
async def func():
nonlocal raised
async with cond:
with self.assertRaises(asyncio.CancelledError) as err:
await cond.wait_for(lambda: wake)
raised = err.exception
raise raised
task = asyncio.create_task(func())
await asyncio.sleep(0)
# Task is waiting on the condition
await cond.acquire()
wake = True
cond.notify()
await asyncio.sleep(0)
# Task is now trying to re-acquire the lock, cancel it there.
task.cancel(msg="foo")
cond.release()
with self.assertRaises(asyncio.CancelledError) as err:
await task
self.assertEqual(err.exception.args, ("foo",))
# We should have got the _same_ exception instance as the one
# originally raised.
self.assertIs(err.exception, raised)
async def test_cancelled_wakeup(self):
# Test that a task cancelled at the "same" time as it is woken
# up as part of a Condition.notify() does not result in a lost wakeup.
# This test simulates a cancel while the target task is awaiting initial
# wakeup on the wakeup queue.
condition = asyncio.Condition()
state = 0
async def consumer():
nonlocal state
async with condition:
while True:
await condition.wait_for(lambda: state != 0)
if state < 0:
return
state -= 1
# create two consumers
c = [asyncio.create_task(consumer()) for _ in range(2)]
# wait for them to settle
await asyncio.sleep(0)
async with condition:
# produce one item and wake up one
state += 1
condition.notify(1)
# Cancel it while it is awaiting to be run.
# This cancellation could come from the outside
c[0].cancel()
# now wait for the item to be consumed
# if it doesn't means that our "notify" didn"t take hold.
# because it raced with a cancel()
try:
async with asyncio.timeout(0.01):
await condition.wait_for(lambda: state == 0)
except TimeoutError:
pass
self.assertEqual(state, 0)
# clean up
state = -1
condition.notify_all()
await c[1]
async def test_cancelled_wakeup_relock(self):
# Test that a task cancelled at the "same" time as it is woken
# up as part of a Condition.notify() does not result in a lost wakeup.
# This test simulates a cancel while the target task is acquiring the lock
# again.
condition = asyncio.Condition()
state = 0
async def consumer():
nonlocal state
async with condition:
while True:
await condition.wait_for(lambda: state != 0)
if state < 0:
return
state -= 1
# create two consumers
c = [asyncio.create_task(consumer()) for _ in range(2)]
# wait for them to settle
await asyncio.sleep(0)
async with condition:
# produce one item and wake up one
state += 1
condition.notify(1)
# now we sleep for a bit. This allows the target task to wake up and
# settle on re-aquiring the lock
await asyncio.sleep(0)
# Cancel it while awaiting the lock
# This cancel could come the outside.
c[0].cancel()
# now wait for the item to be consumed
# if it doesn't means that our "notify" didn"t take hold.
# because it raced with a cancel()
try:
async with asyncio.timeout(0.01):
await condition.wait_for(lambda: state == 0)
except TimeoutError:
pass
self.assertEqual(state, 0)
# clean up
state = -1
condition.notify_all()
await c[1]
class SemaphoreTests(unittest.IsolatedAsyncioTestCase):
def test_initial_value_zero(self):
sem = asyncio.Semaphore(0)
self.assertTrue(sem.locked())
async def test_repr(self):
sem = asyncio.Semaphore()
self.assertTrue(repr(sem).endswith('[unlocked, value:1]>'))
self.assertTrue(RGX_REPR.match(repr(sem)))
await sem.acquire()
self.assertTrue(repr(sem).endswith('[locked]>'))
self.assertTrue('waiters' not in repr(sem))
self.assertTrue(RGX_REPR.match(repr(sem)))
if sem._waiters is None:
sem._waiters = collections.deque()
sem._waiters.append(mock.Mock())
self.assertTrue('waiters:1' in repr(sem))
self.assertTrue(RGX_REPR.match(repr(sem)))
sem._waiters.append(mock.Mock())
self.assertTrue('waiters:2' in repr(sem))
self.assertTrue(RGX_REPR.match(repr(sem)))
async def test_semaphore(self):
sem = asyncio.Semaphore()
self.assertEqual(1, sem._value)
with self.assertRaisesRegex(
TypeError,
"'Semaphore' object can't be awaited",
):
await sem
self.assertFalse(sem.locked())
self.assertEqual(1, sem._value)
def test_semaphore_value(self):
self.assertRaises(ValueError, asyncio.Semaphore, -1)
async def test_acquire(self):
sem = asyncio.Semaphore(3)
result = []
self.assertTrue(await sem.acquire())
self.assertTrue(await sem.acquire())
self.assertFalse(sem.locked())
async def c1(result):
await sem.acquire()
result.append(1)
return True
async def c2(result):
await sem.acquire()
result.append(2)
return True
async def c3(result):
await sem.acquire()
result.append(3)
return True
async def c4(result):
await sem.acquire()
result.append(4)
return True
t1 = asyncio.create_task(c1(result))
t2 = asyncio.create_task(c2(result))
t3 = asyncio.create_task(c3(result))
await asyncio.sleep(0)
self.assertEqual([1], result)
self.assertTrue(sem.locked())
self.assertEqual(2, len(sem._waiters))
self.assertEqual(0, sem._value)
t4 = asyncio.create_task(c4(result))
sem.release()
sem.release()
self.assertEqual(0, sem._value)
await asyncio.sleep(0)
self.assertEqual(0, sem._value)
self.assertEqual(3, len(result))
self.assertTrue(sem.locked())
self.assertEqual(1, len(sem._waiters))
self.assertEqual(0, sem._value)
self.assertTrue(t1.done())
self.assertTrue(t1.result())
race_tasks = [t2, t3, t4]
done_tasks = [t for t in race_tasks if t.done() and t.result()]
self.assertEqual(2, len(done_tasks))
# cleanup locked semaphore
sem.release()
await asyncio.gather(*race_tasks)
async def test_acquire_cancel(self):
sem = asyncio.Semaphore()
await sem.acquire()
acquire = asyncio.create_task(sem.acquire())
asyncio.get_running_loop().call_soon(acquire.cancel)
with self.assertRaises(asyncio.CancelledError):
await acquire
self.assertTrue((not sem._waiters) or
all(waiter.done() for waiter in sem._waiters))
async def test_acquire_cancel_before_awoken(self):
sem = asyncio.Semaphore(value=0)
t1 = asyncio.create_task(sem.acquire())
t2 = asyncio.create_task(sem.acquire())
t3 = asyncio.create_task(sem.acquire())
t4 = asyncio.create_task(sem.acquire())
await asyncio.sleep(0)
t1.cancel()
t2.cancel()
sem.release()
await asyncio.sleep(0)
await asyncio.sleep(0)
num_done = sum(t.done() for t in [t3, t4])
self.assertEqual(num_done, 1)
self.assertTrue(t3.done())
self.assertFalse(t4.done())
t3.cancel()
t4.cancel()
await asyncio.sleep(0)
async def test_acquire_hang(self):
sem = asyncio.Semaphore(value=0)
t1 = asyncio.create_task(sem.acquire())
t2 = asyncio.create_task(sem.acquire())
await asyncio.sleep(0)
t1.cancel()
sem.release()
await asyncio.sleep(0)
await asyncio.sleep(0)
self.assertTrue(sem.locked())
self.assertTrue(t2.done())
async def test_acquire_no_hang(self):
sem = asyncio.Semaphore(1)
async def c1():
async with sem:
await asyncio.sleep(0)
t2.cancel()
async def c2():
async with sem:
self.assertFalse(True)
t1 = asyncio.create_task(c1())
t2 = asyncio.create_task(c2())
r1, r2 = await asyncio.gather(t1, t2, return_exceptions=True)
self.assertTrue(r1 is None)
self.assertTrue(isinstance(r2, asyncio.CancelledError))
await asyncio.wait_for(sem.acquire(), timeout=1.0)
def test_release_not_acquired(self):
sem = asyncio.BoundedSemaphore()
self.assertRaises(ValueError, sem.release)
async def test_release_no_waiters(self):
sem = asyncio.Semaphore()
await sem.acquire()
self.assertTrue(sem.locked())
sem.release()
self.assertFalse(sem.locked())
async def test_acquire_fifo_order(self):
sem = asyncio.Semaphore(1)
result = []
async def coro(tag):
await sem.acquire()
result.append(f'{tag}_1')
await asyncio.sleep(0.01)
sem.release()
await sem.acquire()
result.append(f'{tag}_2')
await asyncio.sleep(0.01)
sem.release()
async with asyncio.TaskGroup() as tg:
tg.create_task(coro('c1'))
tg.create_task(coro('c2'))
tg.create_task(coro('c3'))
self.assertEqual(
['c1_1', 'c2_1', 'c3_1', 'c1_2', 'c2_2', 'c3_2'],
result
)
async def test_acquire_fifo_order_2(self):
sem = asyncio.Semaphore(1)
result = []
async def c1(result):
await sem.acquire()
result.append(1)
return True
async def c2(result):
await sem.acquire()
result.append(2)
sem.release()
await sem.acquire()
result.append(4)
return True
async def c3(result):
await sem.acquire()
result.append(3)
return True
t1 = asyncio.create_task(c1(result))
t2 = asyncio.create_task(c2(result))
t3 = asyncio.create_task(c3(result))
await asyncio.sleep(0)
sem.release()
sem.release()
tasks = [t1, t2, t3]
await asyncio.gather(*tasks)
self.assertEqual([1, 2, 3, 4], result)
async def test_acquire_fifo_order_3(self):
sem = asyncio.Semaphore(0)
result = []
async def c1(result):
await sem.acquire()
result.append(1)
return True
async def c2(result):
await sem.acquire()
result.append(2)
return True
async def c3(result):
await sem.acquire()
result.append(3)
return True
t1 = asyncio.create_task(c1(result))
t2 = asyncio.create_task(c2(result))
t3 = asyncio.create_task(c3(result))
await asyncio.sleep(0)
t1.cancel()
await asyncio.sleep(0)
sem.release()
sem.release()
tasks = [t1, t2, t3]
await asyncio.gather(*tasks, return_exceptions=True)
self.assertEqual([2, 3], result)
async def test_acquire_fifo_order_4(self):
# Test that a successful `acquire()` will wake up multiple Tasks
# that were waiting in the Semaphore queue due to FIFO rules.
sem = asyncio.Semaphore(0)
result = []
count = 0
async def c1(result):
# First task immediately waits for semaphore. It will be awoken by c2.
self.assertEqual(sem._value, 0)
await sem.acquire()
# We should have woken up all waiting tasks now.
self.assertEqual(sem._value, 0)
# Create a fourth task. It should run after c3, not c2.
nonlocal t4
t4 = asyncio.create_task(c4(result))
result.append(1)
return True
async def c2(result):
# The second task begins by releasing semaphore three times,
# for c1, c2, and c3.
sem.release()
sem.release()
sem.release()
self.assertEqual(sem._value, 2)
# It is locked, because c1 hasn't woken up yet.
self.assertTrue(sem.locked())
await sem.acquire()
result.append(2)
return True
async def c3(result):
await sem.acquire()
self.assertTrue(sem.locked())
result.append(3)
return True
async def c4(result):
result.append(4)
return True
t1 = asyncio.create_task(c1(result))
t2 = asyncio.create_task(c2(result))
t3 = asyncio.create_task(c3(result))
t4 = None
await asyncio.sleep(0)
# Three tasks are in the queue, the first hasn't woken up yet.
self.assertEqual(sem._value, 2)
self.assertEqual(len(sem._waiters), 3)
await asyncio.sleep(0)
tasks = [t1, t2, t3, t4]
await asyncio.gather(*tasks)
self.assertEqual([1, 2, 3, 4], result)
class BarrierTests(unittest.IsolatedAsyncioTestCase):
async def asyncSetUp(self):
await super().asyncSetUp()
self.N = 5
def make_tasks(self, n, coro):
tasks = [asyncio.create_task(coro()) for _ in range(n)]
return tasks
async def gather_tasks(self, n, coro):
tasks = self.make_tasks(n, coro)
res = await asyncio.gather(*tasks)
return res, tasks
async def test_barrier(self):
barrier = asyncio.Barrier(self.N)
self.assertIn("filling", repr(barrier))
with self.assertRaisesRegex(
TypeError,
"'Barrier' object can't be awaited",
):
await barrier
self.assertIn("filling", repr(barrier))
async def test_repr(self):
barrier = asyncio.Barrier(self.N)
self.assertTrue(RGX_REPR.match(repr(barrier)))
self.assertIn("filling", repr(barrier))
waiters = []
async def wait(barrier):
await barrier.wait()
incr = 2
for i in range(incr):
waiters.append(asyncio.create_task(wait(barrier)))
await asyncio.sleep(0)
self.assertTrue(RGX_REPR.match(repr(barrier)))
self.assertTrue(f"waiters:{incr}/{self.N}" in repr(barrier))
self.assertIn("filling", repr(barrier))
# create missing waiters
for i in range(barrier.parties - barrier.n_waiting):
waiters.append(asyncio.create_task(wait(barrier)))
await asyncio.sleep(0)
self.assertTrue(RGX_REPR.match(repr(barrier)))
self.assertIn("draining", repr(barrier))
# add a part of waiters
for i in range(incr):
waiters.append(asyncio.create_task(wait(barrier)))
await asyncio.sleep(0)
# and reset
await barrier.reset()
self.assertTrue(RGX_REPR.match(repr(barrier)))
self.assertIn("resetting", repr(barrier))
# add a part of waiters again
for i in range(incr):
waiters.append(asyncio.create_task(wait(barrier)))
await asyncio.sleep(0)
# and abort
await barrier.abort()
self.assertTrue(RGX_REPR.match(repr(barrier)))
self.assertIn("broken", repr(barrier))
self.assertTrue(barrier.broken)
# suppress unhandled exceptions
await asyncio.gather(*waiters, return_exceptions=True)
async def test_barrier_parties(self):
self.assertRaises(ValueError, lambda: asyncio.Barrier(0))
self.assertRaises(ValueError, lambda: asyncio.Barrier(-4))
self.assertIsInstance(asyncio.Barrier(self.N), asyncio.Barrier)
async def test_context_manager(self):
self.N = 3
barrier = asyncio.Barrier(self.N)
results = []
async def coro():
async with barrier as i:
results.append(i)
await self.gather_tasks(self.N, coro)
self.assertListEqual(sorted(results), list(range(self.N)))
self.assertEqual(barrier.n_waiting, 0)
self.assertFalse(barrier.broken)
async def test_filling_one_task(self):
barrier = asyncio.Barrier(1)
async def f():
async with barrier as i:
return True
ret = await f()
self.assertTrue(ret)
self.assertEqual(barrier.n_waiting, 0)
self.assertFalse(barrier.broken)
async def test_filling_one_task_twice(self):
barrier = asyncio.Barrier(1)
t1 = asyncio.create_task(barrier.wait())
await asyncio.sleep(0)
self.assertEqual(barrier.n_waiting, 0)
t2 = asyncio.create_task(barrier.wait())
await asyncio.sleep(0)
self.assertEqual(t1.result(), t2.result())
self.assertEqual(t1.done(), t2.done())
self.assertEqual(barrier.n_waiting, 0)
self.assertFalse(barrier.broken)
async def test_filling_task_by_task(self):
self.N = 3
barrier = asyncio.Barrier(self.N)
t1 = asyncio.create_task(barrier.wait())
await asyncio.sleep(0)
self.assertEqual(barrier.n_waiting, 1)
self.assertIn("filling", repr(barrier))
t2 = asyncio.create_task(barrier.wait())
await asyncio.sleep(0)
self.assertEqual(barrier.n_waiting, 2)
self.assertIn("filling", repr(barrier))
t3 = asyncio.create_task(barrier.wait())
await asyncio.sleep(0)
await asyncio.wait([t1, t2, t3])
self.assertEqual(barrier.n_waiting, 0)
self.assertFalse(barrier.broken)
async def test_filling_tasks_wait_twice(self):
barrier = asyncio.Barrier(self.N)
results = []
async def coro():
async with barrier:
results.append(True)
async with barrier:
results.append(False)
await self.gather_tasks(self.N, coro)
self.assertEqual(len(results), self.N*2)
self.assertEqual(results.count(True), self.N)
self.assertEqual(results.count(False), self.N)
self.assertEqual(barrier.n_waiting, 0)
self.assertFalse(barrier.broken)
async def test_filling_tasks_check_return_value(self):
barrier = asyncio.Barrier(self.N)
results1 = []
results2 = []
async def coro():
async with barrier:
results1.append(True)
async with barrier as i:
results2.append(True)
return i
res, _ = await self.gather_tasks(self.N, coro)
self.assertEqual(len(results1), self.N)
self.assertTrue(all(results1))
self.assertEqual(len(results2), self.N)
self.assertTrue(all(results2))
self.assertListEqual(sorted(res), list(range(self.N)))
self.assertEqual(barrier.n_waiting, 0)
self.assertFalse(barrier.broken)
async def test_draining_state(self):
barrier = asyncio.Barrier(self.N)
results = []
async def coro():
async with barrier:
# barrier state change to filling for the last task release
results.append("draining" in repr(barrier))
await self.gather_tasks(self.N, coro)
self.assertEqual(len(results), self.N)
self.assertEqual(results[-1], False)
self.assertTrue(all(results[:self.N-1]))
self.assertEqual(barrier.n_waiting, 0)
self.assertFalse(barrier.broken)
async def test_blocking_tasks_while_draining(self):
rewait = 2
barrier = asyncio.Barrier(self.N)
barrier_nowaiting = asyncio.Barrier(self.N - rewait)
results = []
rewait_n = rewait
counter = 0
async def coro():
nonlocal rewait_n
# first time waiting
await barrier.wait()
# after waiting once for all tasks
if rewait_n > 0:
rewait_n -= 1
# wait again only for rewait tasks
await barrier.wait()
else:
# wait for end of draining state
await barrier_nowaiting.wait()
# wait for other waiting tasks
await barrier.wait()
# a success means that barrier_nowaiting
# was waited for exactly N-rewait=3 times
await self.gather_tasks(self.N, coro)
async def test_filling_tasks_cancel_one(self):
self.N = 3
barrier = asyncio.Barrier(self.N)
results = []
async def coro():
await barrier.wait()
results.append(True)
t1 = asyncio.create_task(coro())
await asyncio.sleep(0)
self.assertEqual(barrier.n_waiting, 1)
t2 = asyncio.create_task(coro())
await asyncio.sleep(0)
self.assertEqual(barrier.n_waiting, 2)
t1.cancel()
await asyncio.sleep(0)
self.assertEqual(barrier.n_waiting, 1)
with self.assertRaises(asyncio.CancelledError):
await t1
self.assertTrue(t1.cancelled())
t3 = asyncio.create_task(coro())
await asyncio.sleep(0)
self.assertEqual(barrier.n_waiting, 2)
t4 = asyncio.create_task(coro())
await asyncio.gather(t2, t3, t4)
self.assertEqual(len(results), self.N)
self.assertTrue(all(results))
self.assertEqual(barrier.n_waiting, 0)
self.assertFalse(barrier.broken)
async def test_reset_barrier(self):
barrier = asyncio.Barrier(1)
asyncio.create_task(barrier.reset())
await asyncio.sleep(0)
self.assertEqual(barrier.n_waiting, 0)
self.assertFalse(barrier.broken)
async def test_reset_barrier_while_tasks_waiting(self):
barrier = asyncio.Barrier(self.N)
results = []
async def coro():
try:
await barrier.wait()
except asyncio.BrokenBarrierError:
results.append(True)
async def coro_reset():
await barrier.reset()
# N-1 tasks waiting on barrier with N parties
tasks = self.make_tasks(self.N-1, coro)
await asyncio.sleep(0)
# reset the barrier
asyncio.create_task(coro_reset())
await asyncio.gather(*tasks)
self.assertEqual(len(results), self.N-1)
self.assertTrue(all(results))
self.assertEqual(barrier.n_waiting, 0)
self.assertNotIn("resetting", repr(barrier))
self.assertFalse(barrier.broken)
async def test_reset_barrier_when_tasks_half_draining(self):
barrier = asyncio.Barrier(self.N)
results1 = []
rest_of_tasks = self.N//2
async def coro():
try:
await barrier.wait()
except asyncio.BrokenBarrierError:
# catch here waiting tasks
results1.append(True)
else:
# here drained task outside the barrier
if rest_of_tasks == barrier._count:
# tasks outside the barrier
await barrier.reset()
await self.gather_tasks(self.N, coro)
self.assertEqual(results1, [True]*rest_of_tasks)
self.assertEqual(barrier.n_waiting, 0)
self.assertNotIn("resetting", repr(barrier))
self.assertFalse(barrier.broken)
async def test_reset_barrier_when_tasks_half_draining_half_blocking(self):
barrier = asyncio.Barrier(self.N)
results1 = []
results2 = []
blocking_tasks = self.N//2
count = 0
async def coro():
nonlocal count
try:
await barrier.wait()
except asyncio.BrokenBarrierError:
# here catch still waiting tasks
results1.append(True)
# so now waiting again to reach nb_parties
await barrier.wait()
else:
count += 1
if count > blocking_tasks:
# reset now: raise asyncio.BrokenBarrierError for waiting tasks
await barrier.reset()
# so now waiting again to reach nb_parties
await barrier.wait()
else:
try:
await barrier.wait()
except asyncio.BrokenBarrierError:
# here no catch - blocked tasks go to wait
results2.append(True)
await self.gather_tasks(self.N, coro)
self.assertEqual(results1, [True]*blocking_tasks)
self.assertEqual(results2, [])
self.assertEqual(barrier.n_waiting, 0)
self.assertNotIn("resetting", repr(barrier))
self.assertFalse(barrier.broken)
async def test_reset_barrier_while_tasks_waiting_and_waiting_again(self):
barrier = asyncio.Barrier(self.N)
results1 = []
results2 = []
async def coro1():
try:
await barrier.wait()
except asyncio.BrokenBarrierError:
results1.append(True)
finally:
await barrier.wait()
results2.append(True)
async def coro2():
async with barrier:
results2.append(True)
tasks = self.make_tasks(self.N-1, coro1)
# reset barrier, N-1 waiting tasks raise an BrokenBarrierError
asyncio.create_task(barrier.reset())
await asyncio.sleep(0)
# complete waiting tasks in the `finally`
asyncio.create_task(coro2())
await asyncio.gather(*tasks)
self.assertFalse(barrier.broken)
self.assertEqual(len(results1), self.N-1)
self.assertTrue(all(results1))
self.assertEqual(len(results2), self.N)
self.assertTrue(all(results2))
self.assertEqual(barrier.n_waiting, 0)
async def test_reset_barrier_while_tasks_draining(self):
barrier = asyncio.Barrier(self.N)
results1 = []
results2 = []
results3 = []
count = 0
async def coro():
nonlocal count
i = await barrier.wait()
count += 1
if count == self.N:
# last task exited from barrier
await barrier.reset()
# wait here to reach the `parties`
await barrier.wait()
else:
try:
# second waiting
await barrier.wait()
# N-1 tasks here
results1.append(True)
except Exception as e:
# never goes here
results2.append(True)
# Now, pass the barrier again
# last wait, must be completed
k = await barrier.wait()
results3.append(True)
await self.gather_tasks(self.N, coro)
self.assertFalse(barrier.broken)
self.assertTrue(all(results1))
self.assertEqual(len(results1), self.N-1)
self.assertEqual(len(results2), 0)
self.assertEqual(len(results3), self.N)
self.assertTrue(all(results3))
self.assertEqual(barrier.n_waiting, 0)
async def test_abort_barrier(self):
barrier = asyncio.Barrier(1)
asyncio.create_task(barrier.abort())
await asyncio.sleep(0)
self.assertEqual(barrier.n_waiting, 0)
self.assertTrue(barrier.broken)
async def test_abort_barrier_when_tasks_half_draining_half_blocking(self):
barrier = asyncio.Barrier(self.N)
results1 = []
results2 = []
blocking_tasks = self.N//2
count = 0
async def coro():
nonlocal count
try:
await barrier.wait()
except asyncio.BrokenBarrierError:
# here catch tasks waiting to drain
results1.append(True)
else:
count += 1
if count > blocking_tasks:
# abort now: raise asyncio.BrokenBarrierError for all tasks
await barrier.abort()
else:
try:
await barrier.wait()
except asyncio.BrokenBarrierError:
# here catch blocked tasks (already drained)
results2.append(True)
await self.gather_tasks(self.N, coro)
self.assertTrue(barrier.broken)
self.assertEqual(results1, [True]*blocking_tasks)
self.assertEqual(results2, [True]*(self.N-blocking_tasks-1))
self.assertEqual(barrier.n_waiting, 0)
self.assertNotIn("resetting", repr(barrier))
async def test_abort_barrier_when_exception(self):
# test from threading.Barrier: see `lock_tests.test_reset`
barrier = asyncio.Barrier(self.N)
results1 = []
results2 = []
async def coro():
try:
async with barrier as i :
if i == self.N//2:
raise RuntimeError
async with barrier:
results1.append(True)
except asyncio.BrokenBarrierError:
results2.append(True)
except RuntimeError:
await barrier.abort()
await self.gather_tasks(self.N, coro)
self.assertTrue(barrier.broken)
self.assertEqual(len(results1), 0)
self.assertEqual(len(results2), self.N-1)
self.assertTrue(all(results2))
self.assertEqual(barrier.n_waiting, 0)
async def test_abort_barrier_when_exception_then_resetting(self):
# test from threading.Barrier: see `lock_tests.test_abort_and_reset`
barrier1 = asyncio.Barrier(self.N)
barrier2 = asyncio.Barrier(self.N)
results1 = []
results2 = []
results3 = []
async def coro():
try:
i = await barrier1.wait()
if i == self.N//2:
raise RuntimeError
await barrier1.wait()
results1.append(True)
except asyncio.BrokenBarrierError:
results2.append(True)
except RuntimeError:
await barrier1.abort()
# Synchronize and reset the barrier. Must synchronize first so
# that everyone has left it when we reset, and after so that no
# one enters it before the reset.
i = await barrier2.wait()
if i == self.N//2:
await barrier1.reset()
await barrier2.wait()
await barrier1.wait()
results3.append(True)
await self.gather_tasks(self.N, coro)
self.assertFalse(barrier1.broken)
self.assertEqual(len(results1), 0)
self.assertEqual(len(results2), self.N-1)
self.assertTrue(all(results2))
self.assertEqual(len(results3), self.N)
self.assertTrue(all(results3))
self.assertEqual(barrier1.n_waiting, 0)
if __name__ == '__main__':
unittest.main()
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