"""This test checks for correct wait4() behavior.

"""

import os

import time

from test.fork_wait import ForkWait

from test.test_support import TestSkipped, run_unittest, reap_children

try:

    os.fork

except AttributeError:

    raise TestSkipped, "os.fork not defined -- skipping test_wait4"

try:

    os.wait4

except AttributeError:

    raise TestSkipped, "os.wait4 not defined -- skipping test_wait4"

class Wait4Test(ForkWait):

    def wait_impl(self, cpid):

        for i in range(10):

            # wait4() 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, rusage = os.wait4(cpid, os.WNOHANG)

            if spid == cpid:

                break

            time.sleep(1.0)

        self.assertEqual(spid, cpid)

        self.assertEqual(status, 0, "cause = %d, exit = %d" % (status&0xff, status>>8))

        self.assertTrue(rusage)

def test_main():

    run_unittest(Wait4Test)

    reap_children()

if __name__ == "__main__":

    test_main()