to have before being able to take the brokers test?

I don't know about your state, but in NJ it's not about closings it about experience. Here you need three years full time experience to be able to get your broker's license. I know some other states are much easier.

I think it is measured by hours of experience. For residential I think it is 2000 hours for WA state. It may be different from state to state. I have no idea how the hours are measure other than how many hours you worked for a broker.