Programming :: MySQL Security - Remove The Ability To Make Test Databases?

I know very little about MySQL, but I've got some users that need it for testing on a Linux server.So I had set it up a while back, but now I'm running into some small problems.Right now, each user has his own database that I created and can do whatever with it. Each user only sees their own database.I didn't want them to be able to create new databases at all, but they can and when they do anyone can see them.

EDIT(Apparently they can only create databases beginning with the word "test" in the name)

I need to either:

1) Stop them from creating new databases (without affecting their ability to interact with the existing database)

OR

2) Make it so that when they create a database, only they have privileges on it and only they can see it (except mysql root of course).

Anybody know the statement to set these kinds privileges up?

EDIT: pfft... I've a read a bit more and realize that this is an intended part of the installation.

EDIT2

I'd still like to remove the ability to make test databases.

EDIT3:Ok, for reference this is how you prevent users from making and using test databases:

shell> mysql -u root -p
Enter password: (enter root password here)
mysql> DELETE FROM mysql.db WHERE Db LIKE 'test%';
mysql> FLUSH PRIVILEGES;