Found flaky unit test in Knox:
The problem occurs when the run is a little bit slower. The directory deletion during test cleanup fails due to missing directories. The directories are being deleted by Knox TopologyService.
The problem in code where the second deletion is failing sometimes:
Due to removing working directories are being deleted during cleanupSuite I suggest remove deployment directory ignoring file-not-found errors. For example:
Place a breakpoint at the deployment deletion and then slowly follow the steps. During in a file browser the deletion can be seen.