Using fault injection to increase software test coverage

During testing, it is nearly impossible to run all statements or branches of a program. It is especially difficult to test the code used to respond to exceptional conditions. This untested code, often the error recovery code, will tend to be an error prone part of a system. We show that test coverage can be increased through an "assertion violation" technique for injecting software faults during execution. Using our prototype tool, Visual C-Patrol (VCP), we were able to substantially increase test branch coverage in four software systems studied.