Is anyone doing a pretest to opt out of taking a full eLearning course?

Summary

We need the ability to allow seasoned employees to take a test to opt out of taking the full course.

Content

Has anyone used a pretest to allow a student to opt out of taking a full course?  How did you do it?  Is it all in the course?  Two separate courses? etc.

Also with this we really want brand new inexperienced employees to have to take the full course.  We are thinking the best way to do this at this point is to make the assessment hard enough that a inexperienced employee couldn't pass it so we only have one course.