How to access anonymous user account in MySQL?
Have them login as test with no password.

To check the existence of such logins, you connect as root into the commandline mysql tool (or some other tool) and run

SHOW GRANTS FOR 'test'@'localhost';
SHOW GRANTS FOR 'test'@'%';


The first will tell you if users can get in from the same machine.  The second will say whether you can get in from arbitrary other machines (assuming no network or firewall limitations).