Using Fault Injection to Increase Software Test Coverage

During testing, it is nearly impossible to run all statments 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. Keywords: software testing, software test coverage, fault injection, error recovery, software reliability, Visual CPatrol. 1. Introduction Developing reliable and fault tolerant software is difficult and requires discipline both in specifying system functionality and in implementing systems correctly. Approaches for developing highly reliable software include the use of formal methods [11, 14, 9], and rigorous testing methods [2, 7, 13]. Te..