Masters Thesis

Mutation-Based Impact Analysis or Where Do My Results Come From?


Evaluating today’s complex software applications is unaccomplishable without effort. The verification of its functional correctness is achievable by testing the software to the extent that the confidence in it is significant enough to establish its overall rightness. The validation regarding stated claims or derived conclusions remains even more troublesome.

In this thesis, I propose a technique to determine the impact of single program components on the eventual result. I consider two program elements as the principal implementation features: functions and constants. The approach utilizes dynamic mutations activatable at runtime to disable particular components. Combined with the derived outcome, the deviation to the concrete result indicates the impact of the disabled element. The awareness of the essential parts of a program provides a more superior understanding of the origins of the outcomes. Hence, the approach could guide a developer to enhance or expand the program to improve the quality of the results. Moreover, the extracted information provides aids for validating scientific applications based on the derived claims or conclusions by researchers, which would reinforce the quality and correctness of their work.

I evaluated the approach on a diverse collection of interacting program components from a set of real-world applications, and the results show that it works in practice. Besides this evaluation, I applied the technique in a realistic environment to the famous AFL fuzz tester. With the results, I generated a modified version of it by deleting unimportant components. This version shows an average increase in the triggered crashes for several subjects.