The reporting on Floyd's alleged doping is pretty curious. One headline read.
"Tour de France winner Floyd Landis has tested positive for the male sex hormone testosterone."
Gee. Is someone, ever so slightly, uninformed about male biology? Most of the stories I can find, leave me with a lot of unanswered questions and also take a guilty approach to the reporting. (There is still the second sample to test. That will happen on Monday.) I bring this up because testing regulations only consider a positive test valid if both samples test positive.
Here's the best information I've found.
This Malcom Gladwell piece, Drugstore Athlete, I discovered via the above article, was the best explanation I could locate on doping tests and how athletes can avoid detection. Section 3 addresses testosterone specifically. This quote sums up doping pretty well.
"The bottom line is that only careless and stupid people ever get caught in drug tests," Charles Yesalis says. "The elite athletes can hire top medical and scientific people to make sure nothing bad happens, and you can't catch them."
If the tests caught Floyd doping, it was a stupid mistake by his support crew. I don't consider that likely at this high level of cycling.