Abstract. Running unit tests suites with contemporary tools such as JUNIT can show the presence of bugs, but not their locations. This is different from checking a program with a compiler, which always points the programmer to the most likely causes of the errors it detects. We argue that there is enough information in test suites and the programs under test to exclude many locations in the source as reasons for the failure of test cases, and further to rank the remaining locations according to derived evidence of their faultiness. We present a framework for the management of fault locators whose error diagnoses are based on data about a program and its test cases, especially as collected during test runs, and demonstrate that it is capable of performing reasonably well using a couple of simple fault locators in different evaluation scenarios.