Comment 22 for bug 1842297

Thanks for your continued work on this, Julian. This code looks good to me, and the tests make me feel much more confident (thanks for bringing in the mocking library too). I've signed off on this code, and added a follow-up to implement my suggestion from the last paragraph of comment #8: user/sandbergja/lp1842297_openathens_integration_signoff

I'll plan to merge this next Wednesday (9/14), to give a chance for any PINES folks to comment on their experience with this in prod and anyone else who may wish to review this.