test_runner: support custom message for expectFailure #61563

Han5991 · 2026-01-28T14:50:42Z

Summary

This PR enhances the expectFailure option in the test runner to accept different types of values, enabling both custom failure labels and robust error validation. This implementation is referenced from and inspired by nodejs/test-runner#10.

Changes

The expectFailure option now supports the following types:

String: Treated as a failure label (reason).

test('bug', { expectFailure: 'Investigating' }, ...);

RegExp / Function / Error Class: Treated as a matcher to validate the thrown error (similar to assert.throws).

test('regex', { expectFailure: /error message/ }, ...);
test('class', { expectFailure: RangeError }, ...);

Object:
- If it contains label or match properties, it's treated as a configuration object.
```
test('config', {
  expectFailure: {
    label: 'Known issue',
    match: /specific error/
  }
}, ...);
```
- Otherwise, it's treated as an object matcher (properties matching).

References

Based on concepts from: doc(proposal): expectFailure label and/or matcher test-runner#10

nodejs-github-bot · 2026-01-28T14:51:15Z

Review requested:

@nodejs/test_runner

doc/api/test.md

JakobJingleheimer

We already have a plan for the value of expectFail: it will soon accept a regular expression to match against.

Han5991 · 2026-01-28T15:25:42Z

We already gave a plan for the value of expectFail: it will soon accept a regular expression to match against.

@JakobJingleheimer
Ah, thanks for the context! I missed that there was an existing plan for error matching.

In that case, I'd be happy to pivot this PR to implement the expectFailure validation logic (accepting a string/regex to match the error) instead of just a message. Does that sound good, or is there someone else already working on it?"

JakobJingleheimer · 2026-01-28T15:33:11Z

@vassudanagunta you were part of the original discussion; did you happen to start an implementation?

To my knowledge though, no-one has started.

I had planned to pick it up next week, but if you would like to do, go ahead.

If you do, I think it would probably be better to start a new PR than to pivot this one. So open a draft and I'll add it to the test-runner team's kanban board so it gets proper visibility.

codecov · 2026-01-28T16:01:01Z

Codecov Report

❌ Patch coverage is 97.43590% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.75%. Comparing base (3819c7f) to head (7145647).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/test_runner/test.js	97.40%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #61563      +/-   ##
==========================================
+ Coverage   89.74%   89.75%   +0.01%     
==========================================
  Files         675      675              
  Lines      204642   204715      +73     
  Branches    39322    39350      +28     
==========================================
+ Hits       183657   183745      +88     
+ Misses      13257    13241      -16     
- Partials     7728     7729       +1

Files with missing lines	Coverage Δ
lib/internal/test_runner/reporter/tap.js	`98.23% <100.00%> (ø)`
lib/internal/test_runner/test.js	`96.84% <97.40%> (-0.49%)`	⬇️

... and 43 files with indirect coverage changes

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vassudanagunta · 2026-01-28T18:23:39Z

@JakobJingleheimer nope, haven't started this, though I had long ago implemented it in node-test-extra (not yet released).

I think it's important to get the requirements nailed. IMHO, #61570.

JakobJingleheimer · 2026-01-28T20:10:19Z

As I said, let's put together a proposal in the nodejs/test_runner repo 🙂

vassudanagunta · 2026-01-28T22:00:28Z

As I said

?

I should start a discussion in that repo?

ljharb · 2026-01-28T22:06:07Z

reviewed before reading the discussion; imo a string should work as in this PR whether or not it also supports accepting a regex.

JakobJingleheimer · 2026-01-28T22:31:51Z

It could do. My concern is supporting this without considering the intended regex feature accidentally precluding that intended feature, or inadvertently creating a breaking change, or creating heavily conflicting PRs (very frustrating for the implementators).

I think we can likely get both; we can easily avoid those problems with a quick proposal so everyone is on the same page 🙂

I should start a discussion in that repo?

Please start a proposal like the ones already in that repo 🙂 https://github.com/nodejs/test-runner/tree/main/proposals we can discuss it in that PR

ljharb · 2026-01-28T22:33:40Z

conflicts fair; as long as the "should expect failure" uses truthiness (does an empty string count as true or false, though?), i can't foresee any semantic collision.

Han5991 · 2026-01-29T02:26:17Z

@ljharb @vassudanagunta

I've opened a proposal PR in the test-runner repository as suggested by @JakobJingleheimer.
It would be great to continue the discussion on the spec details there:
nodejs/test-runner#10

Han5991 · 2026-01-30T02:17:37Z

doc/api/test.md

+  expectFailure: {
+    with: /error message/,
+    message: 'reason for failure',
+  },


Updated the proposal based on the feedback:

Added support for Direct Matchers (e.g., expectFailure: /error/).

Clarified that with is for validation and message is for reasoning.

Noted that expectFailure: 'reason' and { message: 'reason' } are equivalent.

It should all happen in the proposal (I believe I suggested closing this PR in the interim; it can always be re-opened).

I've included it in the proposal. Could you please review it?

nodejs/test-runner#10

Yes, I shall tomorrow when I'm back from holiday.

Okay, I'll close this for now as requested until the proposal is passed. I'll reopen it once we are ready

vassudanagunta

I think this needs to be documented a little better for the user.

vassudanagunta · 2026-02-04T06:53:52Z

doc/api/test.md

That minimum changes to fix the incorrect English is to move "currently" before "returns", and to refer to "test-cases" plural.

But the entire sentence is unnecessarily complex and confusing, needing a rewrite. I'd recommend:

Suggested change

In each of the following, `doTheThing()` fails to return `true`,

vassudanagunta · 2026-02-04T06:55:21Z

doc/api/test.md

Suggested change

but since the tests are flagged `expectFailure`, they pass.

vassudanagunta · 2026-02-04T07:15:28Z

doc/api/test.md

+it('should do the thing', { expectFailure: 'feature not implemented' }, () => {
+  assert.strictEqual(doTheThing(), true);
+});
+


The ability to expect a specific failure deserves some explanation.

Suggested change

```

If the value of `expectFailure` is a

[<RegExp>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp) |

[<Function>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function) |

[<Object>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object) |

[<Error>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error),

the tests will pass only if they throw a matching value.

See [`assert.throws`] for how the each value type is interpreted.

Each of the following tests will fail _despite_ being flagged `expectFailure`

because the failure was not the expected one.

```js

You'll need to add a link to the assert.throws documentation at the bottom of the file.

vassudanagunta · 2026-02-04T07:33:10Z

doc/api/test.md

+  assert.strictEqual(doTheThing(), true);
+});
+
+it('should fail with specific error', {


Finally, I think this example with the {match, label} value should be broken out as the last example with its own explanation, e.g. "To supply both a reason and specific error for assertFailure..."

vassudanagunta · 2026-02-04T07:43:03Z

doc/api/test.md

    thread. If `false`, only one test runs at a time.
    If unspecified, subtests inherit this value from their parent.
    **Default:** `false`.
+  * `expectFailure` {boolean|string|Object} If truthy, the test is expected to


Missing: that you can specify a specific error directly, without a wrapping {match: ...} object. And probably should reference the specific types with a link to assert.throws as I suggested above.

If it seems redundant to do that in two places, the I guess provide all the details in this section and link to here from Expecting tests to fail.

JakobJingleheimer · 2026-02-04T18:26:45Z

@Han5991 the proposal isn't finished / accepted yet (still hasn't been reviewed by the rest of the test-runner team), so I think it's premature to resume this (the proposal isn't a requirement, but I think it's a good idea and will reduce churn, needless re-reviews, etc—and indeed, there was just earlier today another adjustment to align terms). I do appreciate the enthusiasm 😁

It's added to the team's agenda, so it'll get raised at the next meeting.

Han5991 · 2026-02-04T21:49:20Z

Thanks for letting me know. I'll leave it as a draft until the proposal is finalized.

Resolved by proposal

JakobJingleheimer · 2026-02-09T20:05:36Z

@Han5991 the proposal is all set, so full-steam ahead 🙂 (or whatever pace you want)

Han5991 · 2026-02-09T22:39:27Z

@JakobJingleheimer
Thank you for taking the time to let me know!

Normalize expectFailure values to support string labels, direct matchers, and { label, match } objects while validating errors via assert.throws. Update TAP reporting and tests, including function matcher coverage and unexpected-pass behavior, and clarify docs for direct matcher usage.

nodejs-github-bot added needs-ci PRs that need a full CI run. test_runner Issues and PRs related to the test runner subsystem. labels Jan 28, 2026

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Han-sangwook mentioned this pull request Jan 29, 2026

feat: proposal for expectFailure enhancements nodejs/test-runner#9

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doc(proposal): expectFailure label and/or matcher nodejs/test-runner#10

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Han5991 marked this pull request as draft January 31, 2026 07:56

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Han5991 marked this pull request as ready for review February 3, 2026 22:45

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	In each of the following, `doTheThing()` fails to return `true`,

+```
+If the value of `expectFailure` is a
+[<RegExp>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp) |
+[<Function>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function) |
+[<Object>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object) |
+[<Error>](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error),
+the tests will pass only if they throw a matching value.
+See [`assert.throws`] for how the each value type is interpreted.
+Each of the following tests will fail _despite_ being flagged `expectFailure`
+because the failure was not the expected one.
+```js

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References

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