The top-ranked American said the rules implemented by the International Tennis Federation and World Anti-Doping Agency were "over the top."
"I think it's too much," the Australian Open champion said after beating Karolina Sprem 6-1, 6-2 on Thursday in the second round at the Open GDF Suez in Paris. "It's very invasive... Basically, they show up at your house on any day."
Under the WADA code, athletes must specify one hour each day when and where they can be located for testing. Athletes must also tell anti-doping authorities where they will be over the next three months, but they can update this by email or phone message at short notice if it changes.
Top-ranked Rafael Nadal has been one of the most outspoken critics, insisting that forcing top athletes to be available one hour a day for testing amounted to intolerable harassment.