Generating Unit Tests for Concurrent Classes

As computers become more and more powerful, programs are increasingly split up into multiple threads to leverage the power of multi-core CPUs. However, writing correct multi-threaded code is a hard problem, as the programmer has to ensure that all access to shared data is coordinated. Existing automated testing tools for multi-threaded code mainly focus on re-executing existing test cases with different schedules. In this paper, we introduce a novel coverage criterion that enforces concurrent execution of combinations of shared memory access points with different schedules, and present an approach that automatically generates test cases for this coverage criterion. Our CONSUITE prototype demonstrates that this approach can reliably reproduce known concurrency errors, and evaluation on nine complex open source classes revealed three previously unknown data-races.