I've never taken a dance test, so I don't know, but you can get a reskate in MITF.
If you get one, they will tell you the element you need to reskate- and you have to do the entire pattern. Most judges will tell you WHY you are getting it (you were toe pushing, need more power), but not all.
You can take a few seconds to go talk to your coach before you start. Take a deep breathe, and get a drink of water. I had to reskate on my PB test, I didn't do the entire figure eight pattern for forward crossovers, did 3 circles not 4. The judge just said "oh, you were probably nervous- make sure to skate the whole pattern this time."
I've found even the "mean" judges are nice on the first tests. They want you to do well. If they ask you to start a move somewhere you aren't used to, ask them for your "usual" spot- they can only say no, and many will say yes. My PB was double paneled, and they asked me to do the 3-turn pattern (again, another move not there anymore) starting on the foot I don't usually do. My coach told me to NOT do it that way, so I asked if instead of starting on the opposite side of the rink from the other skater, could I follow behind him- there was no problem.
Also- if the rink is really really cold there is no reason to not wear a jacket during moves. I've had a session where judges actually asked that skaters keep them on, even for freeskate...
I bring extras of EVERYTHING, just so I can't worry. A second dress, extra tights, extra laces, blister pads, safety pins, bobby pins- etc. I've never needed any of it. If you are prone to tummy troubles, throw in a bit of medicine. I have needed that.