Complete Shadow Symbolic Execution with Java PathFinder

Regression testing ensures the correctness of the software during its evolution, with special attention on the absence of unintended side-e ects that might be introduced by changes. However, the manual creation of regression test cases, which expose divergent behavior, needs a lot of e ort. A solution is the idea of shadow symbolic execution, which takes a uni ed version of the old and the new programs and performs symbolic execution guided by concrete values to explore the changed behavior. In this work, we adapt the idea of shadow symbolic execution (SSE) and combine complete/standard symbolic execution with the idea of four-way forking to expose diverging behavior. There- fore, our approach attempts to comprehensively test the new be- haviors introduced by a change. We implemented our approach in the tool ShadowJPF+, which performs complete shadow sym- bolic execution on Java bytecode. It is an extension of the tool ShadowJPF, which is based on Symbolic PathFinder. We applied our tool on 79 examples, for which it was able to reveal more di- verging behaviors than common shadow symbolic execution. Ad- ditionally, the approach has been applied on a real-world patch for the Joda-Time library, for which it successfully generated test cases that expose a regression error.