He's already the first rider to be convicted of doping without having been caught doping.
Half of the Telecom team from the 90s admitted to doping after they'd retired, despite none of them having failed a test - Riis claimed he'd been doping throughout the mid-90s.
No one on the Festina team failed a test - they still got banned.
Ivan Basso never failed a test.
Contador only failed a test because of bad luck - his sample was sent to the one lab that could detect the low level he had in his sample.
Jesper Skibby confessed in his autobiography to have been doping for 10 years without getting caught.
Marco Pantani never failed a doping test.
There is also the comment by Bernhard Kohl after he did which was along the lines of "I've been tested a 100 times while doping and only failed one test"

If you put together all the tests taken by those riders above, they've taken comfortably more tests than Armstrong and yet there is just two failed tests in there of which one was arguably very bad luck.
Sadly testing rarely catches the dopers, the main effect of testing is to make them work harder to avoid getting caught.