Tests that require that Redis be present in order to run, fail due to the statement
command = [shutil.which("redis-server"), "--port", str(port)]
This is because the `shutil.which("redis-server")` call returns `None` in the newer code, due to removal of redis (the server) from the list of dependencies.
To work around the issue, I suggest the use of an explicit, albeit temporary, redis database for testing, by modifying the `REDIS_URL` value in the tests sessions. The modification will simply change the URL to point to a new database for the test session, enabling the tests to run unhindered, but also without tainting the production redis databases.
The system was updated to use prefixed keys, and the full tests now run correctly.