What I personally want more than a good test suite in #ActivityPub, and possibly a lower bar, is a good reference implementation.
Specifically, I'd want something that:
Implements all nontrivial requirements of the spec.
Implements a significant percentage of the data vocabulary
Can handle a nontrivial amount of traffic. It doesn't need to be optimized for it, but it can't fall over in a stiff breeze—analysis should be comparable to analysis of a prod system, just at smaller scale
