pytest-forks 1.0.1

Fork helper for pytest

pytest-forks

This is a simple helper for pytest to support tests that fork or that test code that forks.

What it does

forks detects forked children (and grandchildren) that fail to exit cleanly with os._exit and reports them. It waits for all children to exit to ensure the parent doesn't perform tear-downs while any children are still active. It also prevents pytest from generating duplicate reports if a child fails to exit cleanly.

with forks() calls can be safely nested if required.

Limitations

forks cannot detect calls to os._exit in the parent process. This will result in pytest failing to generate a report.

forks cannot detect missing calls to os.waitpid. This will result in unreaped children until pytest itself closes. forks will correctly detect when these unreaped children exit.

forks will not wait for children created through the subprocess module or with os.exec.

How to use it

import os
from pytest_forks import forks

def test_forking_code():
    with forks():
        # call code that forks

def test_forking_test():
    with forks():
        pid = os.fork()
        if pid == 0:
            # do things in the forked child
            os._exit(0)
        # do things in the parent
        os.waitpid(pid, 0)