Vestibular as a test of Portugues

Sorry for my ignorance. I only know medical information as to "Vestibular". Is this theologian?
What are we discussing? I know I had to speak and read with an appointed person. (Failed the first one, so continuing studies. Oh well!)

"Vestibular" is the general name for the entrance exams for Brazilian universities.   Those for the federal and state universities are highly competitive; for the private, for-profit universities, much less so.
Last time I looked, no Vestibular was on the list of tests approved by the MEC to demonstrate proficiency in Portuguese for naturalization purposes.   If you got a good grade on a federal, state, or PUC (Pontifical Catholic University) Vestibular, you could ask the Federal Police if they'd accept it; I wouldn't bother with a private one.

Thanks abthree. Too long ago for me to think University. When I read it I was thinking an issue with equilibrium. Dah!
You all are better men than me going back there in Winter!
Have so may ask about going to US and connecting in NYC & Chicago this time of year. Now with shutdown have weather delays and custom lines are growing.

There is no exemption for vestibular of private universities...

The vestibulares for a lot of the private universities are a joke, and are widely understood as such:  if you have the money to enroll, you're going to get a pass. 
It's hard for me to imagine the FP accepting vestibular results from the federal, state, or PUC systems to satisfy the Portuguese fluency requirement; with private universities, "hard" becomes "impossible".
If you're successful at getting them to do so, please post, as that will be helpful to others.