The test will not be "questions and answers", that's obviously can be cheated.
indeed, once you reach level50 and go to police department, you will apply for a police test, you will be teleported to a private world when there are cases of "non-threat", "most wanted", "yellow" as NPCs(The test should be simple and can be easily understood in 5-10mins). The wannabe cops have to deal with these cases according to the current /crules, if they get %90 score, they will pass the test and be able to be cop.
I think this is better and you will have no excuse if you break cop rules as a cop as you should know all kind of rules/cases that you should deal with without violating the rules.