I favor the last option:
Someone else could write a new, much better version of the test suite
It’s even possible that I can help, but I’m a guile/scheme noob so there’s probably not much I can do with the legacy test suite.
To make sure it is not just me to be scared by scheme, elixir & friends I did a quick, unscientific search for activitypub-related repos on github and got 233 repos with this language distribution:
| number of repos | programming language |
|---|---|
| 30 | Python |
| 25 | Go |
| 23 | PHP |
| 21 | JavaScript |
| 16 | Rust |
| 13 | Ruby |
| 10 | TypeScript |
| 9 | HTML |
| 7 | Elixir |
| 5 | Clojure |
IMHO the test suite should be implemented in a language which is both popular among activitypub hackers, and has good support for testing asynchronous protocols.