test_runner: add mock-timers support for AbortSignal.timeout

[DeveloperViraj]

Fixes: #60509

This PR completes the fix for making AbortSignal.timeout() compatible with
the test runner's mock timers, and adds a regression test to ensure correct
behavior going forward.

What’s included

1. Mock timers fix

• Added "AbortSignal.timeout" as a discrete mock-timers API target.
• Implemented dedicated store/restore handlers for the original
  AbortSignal.timeout property (no silent failures).
• Integrated the mock implementation into the toFake/toReal paths to match
  the design of other mockable timer APIs.
• Restored documentation comments and internal validation that were
  unintentionally removed earlier.

2. New regression test

• Added test/parallel/test-mock-timers-abortsignal-timeout.js
• Verifies that:
  • enabling mock timers with { apis: ['AbortSignal.timeout'] } works
  • mock.tick() correctly triggers abortion after the expected delay

Notes

I created a fresh branch to ensure a clean diff without unrelated changes and
to fully incorporate the feedback from @Renegade334 and @ErickWendel.

Please let me know if you'd like any adjustments to the test or implementation.
Thanks for the clear guidance and review support

[nodejs-github-bot]

Review requested:

• @nodejs/test_runner

[DeveloperViraj]

Hi @Renegade334 @ErickWendel 👋

I’ve opened a fresh PR with a clean branch so it’s easier to review.
All the requested changes have been applied, including the dedicated API
target for AbortSignal.timeout and the new regression test.

Please let me know if anything needs adjusting, happy to update it!
Thanks again for the guidance. 🙏

[codecov]

Codecov Report

❌ Patch coverage is 76.36364% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.52%. Comparing base (3330e5c) to head (ef06137).
⚠️ Report is 7 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/test_runner/mock/mock_timers.js	76.36%	13 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #60751      +/-   ##
==========================================
- Coverage   88.54%   88.52%   -0.02%     
==========================================
  Files         703      703              
  Lines      208252   208306      +54     
  Branches    40153    40160       +7     
==========================================
+ Hits       184391   184413      +22     
- Misses      15869    15893      +24     
- Partials     7992     8000       +8     

Files with missing lines	Coverage Δ
lib/internal/test_runner/mock/mock_timers.js	97.16% <76.36%> (-1.53%)	⬇️

... and 29 files with indirect coverage changes

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[DeveloperViraj]

I've updated both the implementation and the regression test:

Fixed the missing function name & trailing comma issues in mock_timers.js

Cleaned up unused variables

Ensured the mock AbortSignal.timeout() matches Node.js behavior

Updated the test file to avoid restricted syntax and comply with Node’s linting rules

The PR is ready for the next round of review
Let me know if you’d like any additional adjustments!

[Renegade334]

This is looking good! Just a couple of recommended tweaks.

[Renegade334]

Suggested change

	if (NumberIsNaN(delay)) {
	throw new ERR_INVALID_ARG_VALUE('delay', delay, 'delay must be a number');
	}
	validateUint32(delay, 'delay', false);

This should use validateUint32() for consistency with AbortSignal.timeout(). (You'll need to add it to the list of imports from internal/validators.)

[Renegade334]

This docblock should be restored, with the addition of 'AbortSignal.timeout' to the list.

[Renegade334]

Suggested change

	* EnableOptions type:
	*
	* @typedef {object} EnableOptions
	* @property {Array<string>} apis List of timers to enable, defaults to all
	* @typedef {object} EnableOptions
	* @property {SUPPORTED_APIS} apis List of timers to enable, defaults to all

[Renegade334]

Suggested change

	if (this.#realAbortSignalTimeout) {
	ObjectDefineProperty(AbortSignal, 'timeout', this.#realAbortSignalTimeout);
	} else {
	delete AbortSignal.timeout;
	}
	ObjectDefineProperty(AbortSignal, 'timeout', this.#realAbortSignalTimeout);

AbortSignal.timeout() exists in all supported versions of Node.js, so this conditional is unnecessary; the internal property will always be defined if this code is reached.

[StefanStojanovic]

LGTM. Make sure you fix issues found by the linter.

[DeveloperViraj]

All requested updates have now been applied.

Summary of changes:

Updated mock_timers.js according to the reviewer’s feedback

Preserved the required comment and applied all suggested code adjustments

Updated the test file to follow the Node.js test style (including loading common first)

Verified everything locally, all lint issues are resolved

@StefanStojanovic @Renegade334
Please let me know if anything else is needed. Thanks for the review and guidance!

[DeveloperViraj]

@Renegade334
Just a quick follow-up, I’ve applied all the requested changes and fixed all lint issues locally.
If you get a moment, could you please take another look and let me know if anything else is needed?
Thanks a lot for your time and guidance!