Test site has been indexed! What to do??

Hi, I work with a password protected test site. We had to remove the password for a couple of hours and Google indexed the test site while it wasn't password protected anymore. What is the best course of action to deindex it now? Since we put the password back, do you think Google will naturally deindex it, or do I need to do anything else to ask Google to deindex it? We'd rather not deindex the test site if possible as it could deindex the live site too. Thanks!