Code review comment for ~dmzoneill/charm-prometheus-blackbox-exporter:dev/q2-20

Passed lint test, but unit tests are failing with https://pastebin.canonical.com/p/9tnFBtWrd8/, even after I'd added the report dir mentioned in the README. This is a sizable change, and while I appreciate that this is introducing tests where there were none, it would be good to be able to pass the tests introduced and know the change is good. It's likely that there's something on my test env that's different to the author's, which we should be able to document or, better, add to the Makefile etc.

From what I can see so far, the rest of the change looks good.