️ Repo: CI run failures (test failures)

Tooling Suggestion Checklist

• I have tried restarting my IDE and the issue persists.
• I have pulled the latest main branch of the repository.
• I have read and agree to Mocha's Code of Conduct and Contributing Guidelines
• I have searched for related issues and issues with the faq label, but none matched my issue.
• I want to provide a PR to resolve this

Overview

2026-00-16:

• Merged #6349 after a batch of 10 passing runs. CI is very stable right now, we're working on shoring it up and making it easier to fix in the future :)

2026-06-16:

• Merged #6058 to resolve #6037, which should address most of the run failures. We'll keep chipping away at child issues, which are now the best source of truth for up-to-date info :)

2026-03-29:

• "--timeout should allow numeric value" failed once on main: Run 5193

2026-03-23:

• "reruns test when file under --watch-files changes" fails rarely in #5409: Run 4859

2026-02-16: Codecov has been pretty stable recently, and #5409 fixes some reliability issues with --watch tests (see also #5714). 2 out of 20 runs (4875 to 4894) failed, with 3 jobs failing and 3 total tests failing:

• 4880 - reporters:
  • XUnit reporter when 'reporterOptions.output' is provided when fileStream cannot be created when given an invalid pathname
    • "before each" hook for "should throw system error": Timeout of 1000ms exceeded
      • new failure, likely a rare timeout issue, we can double timeout here and monitor
      • possibly new because Mocha previously didn't report hook failures? https://github.com/mochajs/mocha/issues/1955
    • "after each" hook for "should throw system error": TypeError: cleanup is not a function
      • new failure, likely connected to the before each hook failing
• 4880 - Codecov: no test failures
• 4894 - watch: "--watch when enabled reruns test when file matching --watch-files is removed"
  • Should be fixed by #5409 or its followup work
  • This failure is common as can be seen by the many links to this issue from affected PRs. We are prioritizing reviewing that PR to resolve this and other issues promptly :)

Older

2025-11-21: Yes, some checks are now failing due to Codecov. I'll reach out to Codecov support when I have some time.

2025-10-02:

4 of 20 runs (IDs 4283-4302) failed due to test issues, 1 failed due to Coveralls (ref #3943):

Run(s)	Config	Test name	Err msg	Comments
4283	20.19.4 Windows	Mocha "before each" hook for "should delegate Mocha.unloadFile() for each item in its list of files"	Timeout of 1000ms exceeded	new failure
4286	24.6.0 Windows	--parallel pool shutdown during normal ...	expected [ false, true, true ] to have items satisfying false	new failure
4288, 4290	20.19.4 Windows	--watch when enabled reruns test when file under --watch-files changes	expected 1 to be 2	was rare failure before as well

2025-08-17

• Run 4174: --exit tests occasionally fail (~2% chance), re-opened this one at medium priority
• Run 4201: --parallel test failing, increase timeout (2025-08-22), second instance total across thousands of runs of that test

Original overview:

The GitHub action to run all tests on various versions of Node and various operating systems has started returning intermittent test failures again.

• Passing run
• Failing run

The only difference (netlify.toml changed)