Research Focus

Regression testing ensures that changes to a software system do not introduce new bugs or reintroduce old ones. The underlying assumption of regression testing is that tests are deterministic; meaning, they consistently pass or fail if all factors that the tester seeks to control remain the same. Tests that violate this assumption are called flaky tests. In continuous integration (CI), developers integrate their code changes multiple times a day, making comprehensive automated test suites a necessity due to the frequent integrations. Assuming all tests exhibit some level of flakiness, there will inevitably be flaky failures hampering CI and causing high costs.

My research focuses on understanding flaky tests in CI development processes and on supporting developers in addressing them.

Thesis Supervision

Open Topics

Please get in touch if you are interested in guided research or if you need supervision for your master's or bachelor's thesis. Throughout the entire research period, we will meet weekly to discuss results, issues, and the next steps. You will receive feedback on your thesis before submission, giving you the opportunity to further improve your work.

When applying, please include your resume and transcript so that I can assess whether your prior knowledge and experience match the project. Please also state when you would like to start work.

Currently no open topics.

Ongoing and Assigned Topics

Automatically Detecting Flaky Tests in CI

Master

Finished Topics

Supporting Developers in Repairing Flaky Tests in CI	Master
Supporting Developers in Repairing Flaky Tests in CI	Master
Comparing Approaches for Flaky Test Research	Bachelor
Enhanced Debugging of Flaky Test Cases: Automating State Preservation for Efficient Failure Analysis	Bachelor
A Study on Flaky Tests	Master
Automatically Detecting Flaky End-to-End Test Failures Using Code Coverage (with RW)	Master
Reducing Effort for Flaky Test Detection Through Resource Limitation	Bachelor
Analyzing the Effectiveness of Rerunning Tests for Detecting Flaky UI Tests	Bachelor
Reducing Effort for Flaky Test Detection through Dynamic Program Analysis (with DE; Rohde & Schwarz Best Bachelor Award)	Bachelor
Determining Root Causes of Flaky Tests Using System Call Analysis (with DE)	Master

 

Publications

Leinen, F., Perathoner, A., Pretschner, A. (2024). On the Impact of Hitting System Resource Limits on Test Flakiness. In Proceedings of the 46th IEEE/ACM International Conference on Software Engineering: International Flaky Tests Workshop (FTW).

Leinen, F., Elsner, D., Pretschner, A., Stahlbauer, A., Sailer, M., & Jürgens, E. (2024). Cost of Flaky Tests in Continuous Integration: An Industrial Case Study. In Proceedings of the 17th IEEE International Conference on Software Testing, Verification and Validation (accepted for publication).

Wuersching, R.*, Elsner, D.*, Leinen, F., Pretschner, A., Grueneissl, G., Neumeyr, T., Vosseler, T. (2023). Severity-Aware Prioritization of System-Level Regression Tests in Automotive Software. In Proceedings of the 16th IEEE International Conference on Software Testing, Verification and Validation.

Teaching

Semester	Title
WS 2025/26	Seminar: Software Quality	Seminar
	Advanced Topics of Software Engineering
SS 2025	Seminar: Software Quality	Seminar
WS 2024	Seminar: Software Quality	Seminar
SS 2024	Seminar: Software Quality	Seminar
WS 2023/24	Advanced Topics of Software Engineering	Exercise + Tutorial
	Seminar: Software Quality	Seminar
SS 2023	Robust DevOps: Exploring Stability Factors for UI Tests	Practicum
	Seminar: Software Quality	Seminar
WS 2022/23	Seminar: Software Quality	Seminar
SS 2022	Advanced Topics of Software Testing	Tutorial
	Seminar: Software Quality	Seminar
WS 2021/22	Introduction to Informatics	Tutorial