Method sequence generation for multiple object states using dynamic symbolic execution

Software testing in object-oriented programming requires not only test input data, but also method sequences. Method sequences create new instances and change object states as desired. Method sequence generation to get desired object states is challenging. Seeker is one of the state-of-the-art implementation to generate test cases with method sequences. However, the technique generates method sequences to change a value of only a single variable. Therefore, it cannot cover the branches that need to modify values of multiple variables. In this paper, we extend the technique in order to cover branches which require multiple desired object states. The proposed approach detects all related variables in uncovered branches and uses a fitness function to give method sequences an evaluation value to reduce candidate methods. We applied Seeker and the proposed approach to four open source projects. The result shows a 1-5% improvement of branch coverage over Seeker and also indicates that the effectiveness of the proposed approach varies depending on some specific features of projects.