"""
Running this file normally will do nothing but print 'start '
However, if you interrupt it once it's sleeping, it will expose
a subtlety in the Popen code which can result in a parent process's
stdout getting returned in the child process's stdout
"""
import signal
import subprocess
import sys
import time

sys.stdout.write('start ')

def term(signum, sf):
    sys.stdout.write('term ')
    sys.stdout.flush()

signal.signal(signal.SIGTERM, term)
signal.signal(signal.SIGQUIT, term)
signal.signal(signal.SIGINT, term)

def snooze():
    time.sleep(10)

p = subprocess.Popen(['cat'],
                     preexec_fn=snooze,
                     stdin=subprocess.PIPE,
                     stdout=subprocess.PIPE)
out, err = p.communicate('input')
assert out == 'input', "doesn't match 'output': '%s'" % out