This is the official site for registration of Respiratory Therapists. Self assessment and pretests are available here. Be prepared for registration after you graduate!
National Board of Respiratory Care
There are many test prep websites that may be helpful to you -- Don't forget to use the software applications available to you on the library computers! Just click the Microsoft button and choose all programs, then choose Applications -- Medical -- Respiratory.
Here is an internet site with test prep as well: