Okay you need to change the default user group for new registrations.
Control Panel » Registration Settings
There is a field called
Default Group(s) for New Members:
Is is probably set to user select the pre-user group you added.
That will make all new registrations add to that group.
You could then change your test user in Control Panel » Member Management » Edit Profile
Select permissions tab and change the group that user is in to pre-user.
Then at least you can test the rights for the new test user with out adding another test user.
