test: await fire-and-forget waitFor calls in Course.test.jsx

[brian-smith-tcril]

Summary

Four waitFor(...) calls in Course.test.jsx ran without await, so their background polls threw after their own test finished, and Jest misattributed the rejection to whichever test ran next. Three of them also wrapped an un-awaited findByText (which returns a Promise) in the matcher, so those three assertions were vacuous (matching against a promise object, and never awaited). This awaits them so they genuinely assert.

Pre-existing latent bug — the file already documents this class in its it.skip notes (see #1669); the base suite passed only because the leaks' timing happened not to collide. Split out as the bottom of the stack so the sequence-data → React Query conversion (#2011, on top) stays sequence-only — but it's a prerequisite: the async seed timing in #2011 makes the line-351 leak collide reliably and turn the suite red.

What changed

Only src/courseware/course/Course.test.jsx:

• await the fire-and-forget waitFor in "passes handlers to the sequence".
• Rewrite the three "Sequence alerts display" assertions as expect(await screen.findByText(X)).toBeInTheDocument() so they genuinely assert.

Left untouched: three un-awaited waitFors inside it.skip blocks (they don't run).

Testing

npm run types (0 errors), npm run lint (clean), and the full suite green. The four cases pass in isolation and the suite is green consecutively. No production behavior change — with the line-351 waitFor properly awaited, "passes handlers to the sequence" still renders Previous/Next and fires its handlers as before.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.66%. Comparing base (09a89b7) to head (9074e29).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2060      +/-   ##
==========================================
+ Coverage   93.59%   93.66%   +0.06%     
==========================================
  Files         368      368              
  Lines        6015     6015              
  Branches     1420     1383      -37     
==========================================
+ Hits         5630     5634       +4     
+ Misses        369      365       -4     
  Partials       16       16              

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