Mostly because I was curious about how it works, I reverse-engineered the Guile code for the activitypub.rocks test suite and rewrote much of it in Python (trying to keep the original look-and-feel and functionality).
I have a demonstration site running (for now) at https://aptestsuite.stevebate.dev/ and have created a git repo for the source code.
The questionnaire seems to work fine, but the partially-automated aspects of the C2S testing require a C2S-capable server with OAuth 2.0 support. However, that could be modified relatively easily. In any case, that part of the test suite is still a WIP.