On the Effectiveness of Contracts as Test Oracles in the Detection and Diagnosis of Race Conditions and Deadlocks in Concurrent Object-Oriented Software

The idea behind Design by Contract (DbC) is that a method defines a contract stating the requirements a client needs to fulfill to use it, the precondition, and the properties it ensures after its execution, the post condition. Though there exists ample support for DbC for sequential programs, applying DbC to concurrent programs presents several challenges. We have proposed a solution to these challenges in the context of Java as programming language and the Java Modeling language as specification language. This paper presents our findings when applying our DbC technique on an industrial case study to evaluate the ability of contract-based, runtime assertion checking code at detecting and diagnosing race conditions and deadlocks during system testing. The case study is a highly concurrent industrial system from the telecommunications domain, with actual faults. It is the first work to systematically investigate the impact of contract assertions for the detection of race conditions and deadlocks, along with functional properties, in an industrial system.