USE: unified and split execution for exposing divergences between versions.

How to generate an appropriate set of test cases which can effectively show the difference between an old and new version of a program becomes a challenging research topic. In this paper, we consider both control divergence and data divergence to explore the difference between two versions of code. To do so, we present a novel model called Use, which executes the common code only once but has separate execution traces for the different code in a single dynamic symbolic execution instance, to generate test cases efficiently. Furthermore, we leverage Use to expose control and data divergences introduced by a patch. The initial experimental results show that our methods can efficiently and effectively generate test cases demonstrating the divergence between two versions of code.