import os
import subprocess
import sys
import tempfile
import unittest

import interaction_lock


PROBE = """
import fcntl, os, sys
fd = os.open(sys.argv[1], os.O_RDWR)
try:
    fcntl.flock(fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
except BlockingIOError:
    raise SystemExit(23)
raise SystemExit(0)
"""


class InteractionLockTests(unittest.TestCase):
    def probe(self, path):
        return subprocess.run(
            [sys.executable, "-c", PROBE, path],
            check=False,
        ).returncode

    def test_outsider_contention_and_inherited_child_crash(self):
        with tempfile.TemporaryDirectory() as root:
            fd = interaction_lock.acquire(root)
            self.assertIsNotNone(fd)
            _, path = interaction_lock.canonical_lock_path(root)
            self.assertEqual(self.probe(path), 23)

            subprocess.run(
                [sys.executable, "-c", "import os; os._exit(71)"],
                pass_fds=(fd,),
                check=False,
            )
            self.assertEqual(self.probe(path), 23)

            os.close(fd)
            self.assertEqual(self.probe(path), 0)


if __name__ == "__main__":
    unittest.main()