I know things are always changing, but when we were there recently you could only get the $70 optional covid test at Peebles.
At that time they would not email the result so we had to put together an extremely complicated process (involving Moorings office, taxi driver, draft and sign authorization forms and variously photograph, print and email of documents). It worked but what a PITA that was.
We are hoping to go again next month and specifically were looking to fly through SJU to avoid this. Doesn't look like we'll get out of it anymore.