Reproducing Timing-Dependent GUI Flaky Tests in Android Apps via a Single Event Delay

Flaky tests hinder the development process by exhibiting uncertain behavior in regression testing. A flaky test may pass in some runs and fail in others while running on the same code version. The non-deterministic outcome frequently misleads the developers into debugging non-existent faults in the code. To effectively debug the flaky tests, developers need to reproduce them. The industry de facto to reproduce flaky tests is to rerun them multiple times. However, rerunning a flaky test numerous times is time and resource-consuming. This work presents a technique for rapidly and reliably reproducing timing-dependent GUI flaky tests, acknowledged as the most common type of flaky tests in Android apps. Our insight is that flakiness in such tests often stems from event racing on GUI data. Given stack traces of a failure, our technique employs dynamic analysis to infer event races likely leading to the failure and reproduces it by selectively delaying only relevant events involved in these races. Thus, our technique can efficiently reproduce a failure within minimal test runs. The experiments conducted on 80 timingdependent flaky tests collected from 22 widely-used Android apps show our technique is efficient in flaky test failure reproduction. Out of the 80 flaky tests, our technique could successfully reproduce 73 within 1.71 test runs on average. Notably, it exhibited extremely high reliability by consistently reproducing the failure for 20 runs. CCS Concepts • Software and its engineering → Software testing and debugging.