In addition to the track testing there are of course numerous tests at the factory on the bench, dyno, in simulations, etc., under the harshest of conditions. Audi takes tremendous pride in their durability testing much of which comes from the R8 LMS racing program. There are no harsher conditions than full on racing especially 24 Hour endurance races such as the 24 Hours of the Nurburgring with Audi won this past year.
Audi's attention to detail and quality control is absolutely astounding. Check out the video below and see just how much training, work, and testing goes into producing an R8.