Considering that some guests may only come if they know there's precautions, why not tell them?

Why though? If there’s a reason (immunocompromised etc) I can see it, maybe. But just because a test exists? There are so many communicable diseases that could be spread. Are you worried about those? I’m having a hard time understanding the point of testing for one thing but not the many many others.

lol, make sure you wear a mask while walking your dog as well. This is stupid unless you are immune compromised.

You want this to be a happy day. If people are going to refuse even the bare minimum, you don’t need them there.

I would definitely like to have that information ahead of time in as many places as possible as it would make me feel even safer attending. Congrats and best wishes to you and your fiancé!