A tip for future posts....put them in the forums with lots of posts....they see the most traffic.
Yes, psych testing is very common in some places and can be used for a variety of reasons....bonding study, home study, competence findings, stability questions, etc.
If you have to go through one, just be as honest as possible. Nervous is okay....it's fairly uncomfortable to feel like you're "on display." Psychiatrists are more worried by people who are cool....it's not what's expected. Also, it's okay to ask questions.
If you do have to go through a study, you should be able to find some background on the professional appointed to your case by doing a provider search.