Enforce coverage in tests

[wrslatz]

Summary

Enforce a minimum level of coverage across tests. This will ensure important code logic is properly covered by tests. A threshold should be set and enforced in CI.

Context

Not a blocker; to consider for follow-on (could split out to an issue): should we consider running with coverage and enforcing a minimum coverage threshold?

Originally posted by @wrslatz in #454 (comment)

[Miablo]

@wrslatz -- what do you think this min should be? Like 80?

[wrslatz]

@wrslatz -- what do you think this min should be? Like 80?

@Miablo yeah, 80 is probably a good minimum. We can adjust from there and likely increase coverage as we cover uncovered code and exclude code not worth covering.

[Miablo]

Ok just ran the coverage script to see where we are at and these are the results:

Statements : 45.97%
Branches : 36.36%
Functions : 38.33%
Lines : 46.66%

current floor (~45%)

File	Lines	Notes
server/git/	88.9%	Already past 80% — controller.ts 90%, router.ts 50%
server/config/	83.3%	Past 80% — only controller.ts:23-25 uncovered
server/repos/	58.8%	controller.ts core has big gaps (lines 150-280, 293-321)
bot/	44.5%	index.ts is the biggest miss (35.5% — webhook handlers)
server/octokit/	30.8%	controller.ts 20% — almost untested
app/api/auth/lib/	5.95%	auth-options.ts — biggest single drag on the average

Sooooooo - we can either:

1. add more tests to get coverage up to 80% and update the threshold
2. set the threshold to 45 for now to make sure any add-ons don't reduce the current floor then create issues to increase coverage for later

Note: we also have files that are being excluded from coverage. We could add in more files then see where the floor is and then choose option 1 or 2 if it is still below 80. What do you think?

[wrslatz]

I'd review any files currently being excluded and determine whether or not excluding them makes sense. Probably also worth excluding if any other files should be excluded. After that, option 2 (enforcing lower coverage immediately, then going back and increasing coverage) makes sense to me. Hopefully some of these files have easy coverage opportunities.