There is no official PMP pretest, your only option is to take a sample test. A word of caution though, most sample PMP tests out there (including free ones) are written by companies/individuals for the sole reason to make more money off of you. Here's how:
- They offer a free or a cheaply priced sample test, with 200 questions
- You fail the test even after studying very hard
- You enroll to take their insanely priced online courses because you think you will get better
- You take the PMP exam and you discover that it had really little to do with their tests or their online courses.
The thing is the sample tests are intentionally written to be very hard, because they want you to fail, so you can take their courses. Most of the PMP candidates registering for these courses discover that the sample tests and the online courses are now of little relevancy to the real exam, especially when the PMP became a more situational exam.