Simulating the Effect of Test Flakiness on Fault Localization Effectiveness

Test flakiness (non-deterministic behavior of test cases) is an increasingly serious concern in industrial practice. However, there are relatively little research results available that systematically address the analysis and mitigation of this phenomena. The dominant approach to handle flaky tests is still detecting and removing them from automated test executions. However, some reports showed that the amount of flaky test is in many cases so high that we should rather start working on approaches that operate in the presence of flaky tests. In this work, we investigate how test flakiness affects the effectiveness of Spectrum Based Fault Localization (SBFL), a popular class of software Fault Localization (FL), which heavily relies on test case execution outcomes. We performed a simulation based experiment to find out what is the relationship between the level of test flakiness and fault localization effectiveness. Our results could help the users of automated FL methods to understand the implications of flaky tests in this area and to design novel FL algorithms that take into account test flakiness.