Intuition is often not a good guide to know which testing strategies will work best. There is no substitute for experimental analysis based on objective criteria: how many bugs a strategy finds, and how fast. "Random" testing is an example of an idea that intuitively seems simplistic or even dumb, but when assessed through such criteria can yield better results than seemingly smarter strategies. For random testing to be effective, however, one must guarantee that the generated inputs are representative; in particular, they should be evenly spread across the input domain. This is the idea of Adaptive Random Testing (ART). ART was initially proposed for numerical inputs, on which a notion of distance is immediately available. To extend the ideas to the testing of object-oriented software, we have developed a notion of distance between objects and a new testing strategy (ARTOO) which selects objects that have the highest average distance to those already used as test inputs. AR...