Why isn't Djokovic tested for doping?

[olive_triangurl]

http://espn.go.com/tennis/story/_/id/9397854/tennis-lackluster-drug-testing-next
Novak Djokovic revealed in January that he hasn't been randomly blood tested in the prior six or seven months. "It was more regular … two, three years ago. I don't know the reason why they stopped it," he said.

http://www.tennisworldusa.org/ATP---Rafael-Nadal-has-undergone-drug-testing-six-or-seven-times-ahead-of-his-return-articolo8198.html
The eight time French Open champion has been tested for doping four times in two weeks, according to sources close to the player. Overall, Nadal was tested “six or seven” times ahead of his return, ITF president Francesco Ricci Bitti told DPA.

Nadal's tests were conducted in 2013, the year Nadal won 10 titles.
Has Djokovic been tested in 2015?

[Def Leppard]

This is a great question but overall I don't nessisrily trust the results of these tests... To much money in it