SiblingClassTestDetector: Finding Untested Sibling Functions

Methods which are not covered by a project's test suite are especially prone to exhibiting unexpected behaviours and being more challenging to maintain over time. Some methods are untested but have related implementations in sibling classes (sharing a common superclass) that are tested. Our goal is to help developers improve test suites by identifying such untested methods. We have implemented a prototype tool, SiblingClassTestDetector, which accepts programs along with their test suites, and outputs a set of Completable Candidates (CCs). We have applied our prototype tool to 17 open-source benchmarks and identified 107 CCs within these benchmarks. We have also manually produced two tests for Completable Candidates and submitted Pull Requests for these tests, one of which has been merged by developers.