BigBird and kornfeld gave good generalized suggestions; here is what Sonoma has as their requirement:
Sonoma Raceway offers testing with the following requirements and fees. If you have any questions concerning testing or to pre-register, please email firstname.lastname@example.org. Advance registration for testing is required; space is limited.
Valid Competition License from NASCAR, Grand-Am, SCCA, FIA, NASA, SVRA, VARA, INEX, HMSA, CFRA, PCA, BMWCCA, HSR, IMSA, CSRG and Star Mazda.
Rookie, Novice, Provisional, Time Trial licenses, driving school certificates, resumes, and logbooks are NOT substitutions for a Competition License and will not be accepted.
Bring your license with you to sign-in, the morning of your pre-scheduled test day.
Vehicles are to conform to SCCA Pro Racing regulations.
That would leave me out.