You don’t have to be 3 years drug free or so …
BBers participating in the world Championship are requested to apply a certificate of Drug Free (an internal test done by their local federation) at the time of weighing in and the top 5 get drug tested after the show (this year it was a random 3 out of the top 5) the guy who got 2nd place in the 85KG category got caught so did the winner of the 80KG category.