Congratulations, You’re a Certified N.B.A. Agent. Good Luck Finding a Client.

At 10:02 a.m. on a sunny day last winter in the gym at the National Basketball Players Association’s Midtown Manhattan headquarters, dozens of nervous prospective N.B.A. agents sat at folding tables, hunched over the first test many had taken in years. Copies of the N.B.A.’s collective bargaining agreement and regulations governing agents cluttered the tables.…