Golden State Warriors star David Lee tells TMZ ... he thinks the NBA drug testing policy is rock solid -- and believes the reason only 1 guy has tested positive for hard drugs since 2000 is because the players are simply staying clean.
Lee was leaving Hooray Henry's nightclub in L.A. last night when we asked about the drug culture in the NBA -- specifically the statistic that the ONLY person who tested positive for a drug harder than weed in the past 13 years is Chris "Birdman" Andersen.
"I can tell you [the NBA is] very thorough with their testing," Lee told us.
As we reported, multiple NBA sources tell us players have found a loophole in the NBA drug testing policy -- because they're only tested 4 times a year, and after the 4th test "It's like Christmas Day."
But Lee disagrees ... explaining, "Testing is very thorough and very random ... so it's very difficult to try to do that kind of stuff to avoid it."