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import os
import time
import multiprocessing
from sybil import Sybil
from psutil import pid_exists
from doctest import ELLIPSIS, NORMALIZE_WHITESPACE, REPORT_NDIFF
from datetime import timedelta
from tempfile import TemporaryDirectory
from contextlib import ExitStack
from flufl.lock import SEP, Lock
from sybil.parsers.doctest import DocTestParser
from sybil.parsers.codeblock import PythonCodeBlockParser
DOCTEST_FLAGS = ELLIPSIS | NORMALIZE_WHITESPACE | REPORT_NDIFF
def child_locker(filename, lifetime, queue, extra_sleep):
# First, acquire the file lock.
with Lock(filename, lifetime):
# Now inform the parent that we've acquired the lock.
queue.put(True)
# Keep the file lock for a while.
time.sleep(lifetime.seconds + extra_sleep)
def acquire(filename, *, lifetime=None, extra_sleep=-1):
"""Acquire the named lock file in a subprocess."""
queue = multiprocessing.Queue()
proc = multiprocessing.Process(
target=child_locker,
args=(filename, timedelta(seconds=lifetime), queue, extra_sleep))
proc.start()
while not queue.get():
time.sleep(0.1)
def child_waitfor(filename, lifetime, queue):
t0 = time.time()
# Try to acquire the lock.
with Lock(filename, lifetime):
# Tell the parent how long it took to acquire the lock.
queue.put(time.time() - t0)
def waitfor(filename, lifetime):
"""Fire off a child that waits for a lock."""
queue = multiprocessing.Queue()
proc = multiprocessing.Process(
target=child_waitfor,
args=(filename, lifetime, queue))
proc.start()
return queue.get()
def simulate_process_crash(lockfile):
# We simulate an unclean crash of the process holding the lock by
# deliberately fiddling with the pid in the lock file, ensuring that no
# process with the new pid exists.
with open(lockfile) as fp:
filename = fp.read().strip()
lockfile, hostname, pid_str, random = filename.split(SEP)
pid = int(pid_str)
while pid_exists(pid):
pid += 1
with open(lockfile, 'w') as fp:
fp.write(SEP.join((lockfile, hostname, str(pid), random)))
class DoctestNamespace:
def __init__(self):
self._resources = ExitStack()
def setup(self, namespace):
namespace['acquire'] = acquire
namespace['temporary_lockfile'] = self.temporary_lockfile
namespace['waitfor'] = waitfor
namespace['simulate_process_crash'] = simulate_process_crash
def teardown(self, namespace):
self._resources.close()
def temporary_lockfile(self):
lock_dir = self._resources.enter_context(TemporaryDirectory())
return os.path.join(lock_dir, 'test.lck')
namespace = DoctestNamespace()
pytest_collect_file = Sybil(
parsers=[
DocTestParser(optionflags=DOCTEST_FLAGS),
PythonCodeBlockParser(),
],
pattern='*.rst',
setup=namespace.setup,
).pytest()
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