guard_test.py

import time
import sys
import signal
from subprocess import DEVNULL, PIPE, Popen
from functools import partial


signal_value = int(sys.argv[1])
signal_value = signal.Signals(signal_value)
print("Using signal", signal_value)

cmd = ["python", "guard.py", signal_value.name]
make_proc = partial(Popen, cmd)
options = dict(stdout=DEVNULL, stderr=DEVNULL)


start = time.monotonic()
procs = [make_proc(**options) for _ in range(4)]

print("Waiting to finish")
returncodes = set()
for proc in procs:
    returncodes.add(proc.wait())

if len(returncodes) == 1 and returncodes.pop() == signal_value:
    print("All return codes are", signal_value)
else:
    print("Something went wrong.")
    print("Got following return codes", returncodes)


end = time.monotonic()

print(f"Starting, sending signal, waiting to finish took {end-start:.2f} seconds.")