Congratulations! Just remember its natural to be excited and nervous. I think they let you know in advance just to make you nervous. I have been tested three diffrent ways letting me know a week before hand, just walking in the door and being told it's test time, and told at the end of class it's test time. At the end of class is nice, you do not have that much time to be nervous. I always knew I would pass the test just nervous about how good I would do.
So congratulations again your sensei know you are ready.