You can bet that the entire Iranian nuke brain trust will be there. I'd suggest that when they do it, we drop the big one on that site and take them all out at once.
We can say that their test malfunctioned.
I wonder if they would bother to test at all. It's not like plans for a uranium bomb haven't been public for a few decades. If they test and it works, I'd reckon that they would never get another chance to detonate one operationally. Even the Euroweenies would likely come around and realize how dangerous it would be for them. My guess is, if they have one to test they'd skip testing and go operational with it from the get-go.