Q: Writing *.phpt's: How to specify multi-process test?

Good Morning PHP Internals! I'm trying to get some unit test coverage on some functionality that requires two separate processes, and I'm wondering how to do this with a *.phpt. WinCache has a cross-process lock functionality that allows synchronization between two processes. (See: http://php.net/manual/en/function.wincache-lock.php). I looked through https://qa.php.net/write-test.php, but I'm not seeing anything that supports spinning up multiple instances of the test. Is there any special handling a phpt needs to do if it calls exec()? (http://php.net/manual/en/function.exec.php) Thx! --E.