Sorry, I wasn't clear. In JSONWebKeySetTest we're reaching out to a real set of endpoints.
However, I can't seem to find a public OAuth2 server that supports RFC8414 to write a test.
I was thinking of using something like Wiremock to create a fake server so I can stub it out, and wondered if you'd be happy with that as a change to the existing tests in JSONWebKeySetTest?
by 
Jamie Tanna
.