Getting Tested for Autism: What to Expect?

So I finally took the step to talk to my primary about getting tested for Autism since there's some speculation. Unfortunately where I live there seems to be only one doctor who initiates testing for adults since my state has little resources for autism diagnostics so many travel out of state for that but I don't have the ability to do that and they are backed up for awhile. My appt has been scheduled in June of next year. I'm a bit relieved I was able to get an appt but I'm also nervous because I was told testing takes about 5 hours. I've always have had testing anxiety no matter what type of testing whether it be medical or for school since I was younger. I tend to shut out and freeze. What lessens this anxiety to a bit is knowing what to expect so my question is what am to expect during this testing? What types of testing do they do? Do they allow breaks?