I thought that the USFSA instituted a rule requiring the coach's approval for tests, after Michelle Kwan tested before Frank Carroll felt she was ready? (Her father signed the permission form.)
When I was coachless (a friend helped me with my test, in my opinion, she's a coach, but she is uninsured, and unaffiliated with any skating organization), I asked USFS about this. The respnse to my email was that "if you have a coach, you must get approval. If you do not have a coach, then there is no one to get approval from." There is no rule that requires a skater to have a coach.
Skaters can put themselves on the ice for tests and competitions. A coach is not required to be present. However, the only person who can put them on the ice is a coach, you can no longer have a friend stand in.