tools: add lint rule to ensure assertions are reached

[aduh95]

Test assertions that are unreachable are pretty much useless, and it’s not always obvious whether a callback is actually executed. By adding a lint rule that forbids writing assertions in callbacks that are not wrapped with common.mustCall, we should end up with more robust tests.

This is only targeting a few test subdirs, the end goal would be to target more in follow up PRs and eventually the entire test/ dir.

ESlint failures in test/parallel

{glob: 'test/parallel/test-n*', result: '✖ 126 problems (126 errors, 0 warnings)', exitCode: 1 }{glob: 'test/parallel/test-o*', result: '✖ 8 problems (8 errors, 0 warnings)', exitCode: 1 }{glob: 'test/parallel/test-p*', result: '✖ 84 problems (84 errors, 0 warnings)', exitCode: 1 }{glob: 'test/parallel/test-q*', result: '✖ 8 problems (8 errors, 0 warnings)', exitCode: 1 }{glob: 'test/parallel/test-r*', result: '✖ 102 problems (102 errors, 0 warnings)', exitCode: 1 } 

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.52%. Comparing base (e978a63) to head (16ea131).
⚠️ Report is 17 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@## main #60125 +/- ## ========================================== - Coverage 88.53% 88.52% -0.02%  ========================================== Files 703 703 Lines 207833 207825 -8 Branches 40011 40001 -10 ========================================== - Hits 184009 183974 -35 - Misses 15824 15858 +34 + Partials 8000 7993 -7 

see 28 files with indirect coverage changes

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[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/69579/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/69581/

[nodejs-github-bot]

Landed in ec26b1c