1. A method comprising: obtaining a set of results corresponding to a plurality of test patterns and a plurality of events, wherein the results reflect a relationship in which at least one of the test patterns triggers at least one of the events; organizing the set of results based upon an ordering of the corresponding test patterns; and creating a subset of the test patterns based upon the ordered results, wherein each test pattern in the subset triggers at least one event not triggered by any previous test pattern in the ordering.