This read-only BerTestStatus reflects the current lifecycle state of a BERT configuration entry, moving from 'initial' at creation, to 'in-progress' once bertControlAction indicates start, to 'completed' either on an explicit stop or when the test's frame count or time limit is reached autonomously, per its description. An administrator polls this to know whether a BERT run is still active or has finished before trying to read its results. For example, an operator who set bertControlDuration to 3600 seconds would expect bertControlTestStatus to flip from 'in-progress' to 'completed' automatically once that hour elapses, even without manually stopping it.