Testing plugins

[DianaProbst]

Repo file: none
Live page link (and page section): none
Issue description: I cannot find a way of testing plugins automatically, and I think this should be part of the new developer instructions, if there is a way, and if not, there need to be guidelines for best practice in testing. I'm going to be supporting and improving a plug-in long-term, with a long testing list for each iteration.

I know you have your own priorities and difficulties, but I'm here to flag up this would be really important for me, a user of the UXP, to be able to use it effectively and well. If there is a way that I've missed, please do direct me there, and I'll look up where I think the signpost should go, and add it here.