cpython/Lib/test/fork_wait.py
Neal Norwitz 84bc19a453 Restore rev 47014:
The hppa ubuntu box sometimes hangs forever in these tests.  My guess
is that the wait is failing for some reason.  Use WNOHANG, so we won't
wait until the buildbot kills the test suite.

I haven't been able to reproduce the failure, so I'm not sure if
this will help or not.  Hopefully, this change will cause the test
to fail, rather than hang.  That will be better since we will get
the rest of the test results.  It may also help us debug the real problem.

*** The reason this originally failed was because there were many
zombie children outstanding before rev 47158 cleaned them up.
There are still hangs in test_subprocess that need to be addressed,
but that will take more work.  This should close some holes.
2006-07-07 06:03:15 +00:00

78 lines
2.2 KiB
Python

"""This test case provides support for checking forking and wait behavior.
To test different wait behavior, overrise the wait_impl method.
We want fork1() semantics -- only the forking thread survives in the
child after a fork().
On some systems (e.g. Solaris without posix threads) we find that all
active threads survive in the child after a fork(); this is an error.
While BeOS doesn't officially support fork and native threading in
the same application, the present example should work just fine. DC
"""
import os, sys, time, thread, unittest
from test.test_support import TestSkipped
LONGSLEEP = 2
SHORTSLEEP = 0.5
NUM_THREADS = 4
class ForkWait(unittest.TestCase):
def setUp(self):
self.alive = {}
self.stop = 0
def f(self, id):
while not self.stop:
self.alive[id] = os.getpid()
try:
time.sleep(SHORTSLEEP)
except IOError:
pass
def wait_impl(self, cpid):
for i in range(10):
# waitpid() shouldn't hang, but some of the buildbots seem to hang
# in the forking tests. This is an attempt to fix the problem.
spid, status = os.waitpid(cpid, os.WNOHANG)
if spid == cpid:
break
time.sleep(2 * SHORTSLEEP)
self.assertEquals(spid, cpid)
self.assertEquals(status, 0, "cause = %d, exit = %d" % (status&0xff, status>>8))
def test_wait(self):
for i in range(NUM_THREADS):
thread.start_new(self.f, (i,))
time.sleep(LONGSLEEP)
a = self.alive.keys()
a.sort()
self.assertEquals(a, range(NUM_THREADS))
prefork_lives = self.alive.copy()
if sys.platform in ['unixware7']:
cpid = os.fork1()
else:
cpid = os.fork()
if cpid == 0:
# Child
time.sleep(LONGSLEEP)
n = 0
for key in self.alive:
if self.alive[key] != prefork_lives[key]:
n += 1
os._exit(n)
else:
# Parent
self.wait_impl(cpid)
# Tell threads to die
self.stop = 1
time.sleep(2*SHORTSLEEP) # Wait for threads to die