test: more tweaks to certwatcher tests

[tstirrat15]

Description

require.NoError calls t.Fatalf, which kills the goroutine from which it's called. For this reason you're not supposed to use it inside of goroutines, but the callback in RegisterCallback is invoked inside of a goroutine.

I'm not entirely sure that this is the fix, but it probably isn't helping.

Changes

• Use assert instead of require

Testing

Review.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 48.35%. Comparing base (fa85ab8) to head (22159dc).

❌ Your project check has failed because the head coverage (48.35%) is below the target coverage (75.00%). You can increase the head coverage or adjust the target coverage.

❗ There is a different number of reports uploaded between BASE (fa85ab8) and HEAD (22159dc). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (fa85ab8)	HEAD (22159dc)
	25	24

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #3054       +/-   ##
===========================================
- Coverage   73.66%   48.35%   -25.30%     
===========================================
  Files         499      450       -49     
  Lines       60165    56419     -3746     
===========================================
- Hits        44312    27276    -17036     
- Misses      12666    26272    +13606     
+ Partials     3187     2871      -316     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.