"A helicopter rotor shall only be turned under power for the purpose of flight with a qualified pilot at the controls"
So anyone can turn the rotor under power if they have no intention of going flying?
Of course. Engineers ground running etc. No problem.
The issue to be careful of is if the RFM prohibits as in the case of AS350 models which is different depending on the model. (please check as results may vary)
Pretty sure anything up to a B2 is OK and B3's with a more modern RFM sez NO.
If the RFM sez NO your Ops Spec/Manual cannot override it.
Technically to override it you would probably need an STC!