There isn't really testing per se in the Marine Corps... we just have to complete various MCI's (which are kind of like online college courses, which is finished with a test that is proctored online), and we have different schools we have to go to for certain ranks. We get to E-3 based on time in grade alone, then from there your are put up against other Marines, and Ideally only the best get promoted to Corporal and become and NCO (Non-commissioned officer). But remember you have to do the leading Junior Marines MCI now to be eligible.