He is already tested before and after the fight.
This whole thing was a non-issue until six months ago when Mayweather Sr. who has no proof started this.
Again back the original point of that why should Mayweather get to dictate terms that go outside the testing of the athletic commission with no proof? Mosley agreed to it of course because it's a big payday for him and he would have jumped through whatever hoops he had to. Manny doesn't need Mayweather to make big $$$.
I want to see the fight as much as anyone, and I would be fine if Manny just said "ok sure, I'll do this" but I can also see his point and why he already threatened to sue Mayweather for defamation because the guy calling him a cheater without any proof other than he's a really powerful puncher for his weight.