Combining Fault-Injection with Property-Based Testing

In this paper we present a methodology and a platform using Fault Injection (FI) and Property-Based Testing (PBT). PBT is a technique in which test cases are automatically generated from a specification of a system property. The generated test cases vary input stimuli as well as the sequence in which commands are executed. FI is used to accelerate the occurrences of faults in a system to exercise and evaluate fault handling mechanisms and e.g. calculate error detection coverage. By combining the two we have achieved a way of randomly injecting different faults at arbitrary moments in the execution sequence while checking whether certain properties still hold. We use the commercially available tool QuickCheck for generating the test cases and developed FaultCheck for FI. FaultCheck enables the user to utilize fault models, commonly used during FI, from PBT tools like QuickCheck. We demonstrate our method and tools on a simplified example of two Airbag systems that should meet safety requirements. We can easily find a safety violation in one of the examples, whereas by using the AUTOSAR E2E-library implementation, exhaustive testing cannot reveal any such safety violation. This demonstrates that our approach on testing can reveal certain safety violations in a cost-effective way.