Looking for test taking software

I have a computer lab of 60 PCs and I am looking for software that will allow computer based testing in the lab.
I want the teacher to create the test then distribute it to all PC’s. Answers are gathered and placed into a grade book automatically.
This seems pretty basic, but I am looking for a good commercial product that will do this and have never purchased this type of software before. Has anyone had any practical experience with this software?