I wish there was an ActivttyPub tester / data flow simulator that can emulate, like, activity of various Fediverse software for testing compatibility.
Like, you're developing a new AP software, and want to test how well it integrates into the existing instances, and you want to emulate, say for example, a busy Mastodon instance. You just spin this up, point it at your new software, set what kinds of objects and activities you want to exchange, and run it.
I bet, this would've speed up the development of the new AP software significantly.