test_runner: add `context.log()` and `test:log` event by MoLow · Pull Request #64389 · nodejs/node

MoLow · 2026-07-09T09:58:25Z

Add a log(message[, data]) method to TestContext and SuiteContext that emits a new test:log event.

Unlike test:diagnostic, which is buffered so it is emitted in the order tests are defined, test:log is emitted immediately, in the order tests execute, including under process isolation where it bypasses the per-file declaration order buffer.

Motivation for adding this

This gives reporters that render the test tree unbuffered a live, attributed logging channel that captured stdout cannot provide under concurrency (see for example https://www.npmjs.com/package/@reporters/live and https://www.npmjs.com/package/@reporters/web).

The event carries the message, an optional opaque structured payload that the runner passes through untouched, and the emitting test's name, testId, parentId, nesting, and location.

Built-in reporters render it the same way they render test:diagnostic.

nodejs-github-bot · 2026-07-09T09:58:30Z

Review requested:

@nodejs/test_runner

codecov · 2026-07-09T11:38:23Z

Codecov Report

❌ Patch coverage is 97.43590% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 90.25%. Comparing base (7c53fb5) to head (e24d081).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/test_runner/reporter/utils.js	75.00%	1 Missing ⚠️

Additional details and impacted files

@@ Coverage Diff @@## main #64389 +/- ##
=======================================
Coverage 90.24% 90.25% =======================================
Files 741 741 Lines 241375 241410 +35 Branches 45476 45490 +14 =======================================
+ Hits 217822 217876 +54 + Misses 15126 15085 -41 - Partials 8427 8449 +22

Files with missing lines	Coverage Δ
lib/internal/test_runner/reporter/junit.js	`94.76% <100.00%> (+0.03%)`	⬆️
lib/internal/test_runner/reporter/spec.js	`81.81% <100.00%> (+0.12%)`	⬆️
lib/internal/test_runner/reporter/tap.js	`94.89% <100.00%> (+0.01%)`	⬆️
lib/internal/test_runner/runner.js	`94.42% <100.00%> (ø)`
lib/internal/test_runner/test.js	`97.92% <100.00%> (+0.01%)`	⬆️
lib/internal/test_runner/tests_stream.js	`92.95% <100.00%> (+0.45%)`	⬆️
lib/internal/test_runner/reporter/utils.js	`94.54% <75.00%> (-0.74%)`	⬇️

... and 38 files with indirect coverage changes

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nodejs-github-bot · 2026-07-09T13:47:17Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74690/

github-actions · 2026-07-09T23:00:43Z

The notable-changePRs with changes that should be highlighted in changelogs. label has been added by @Renegade334.

Please suggest a text for the release notes if you'd like to include a more detailed summary, then proceed to update the PR description with the text or a link to the notable change suggested text comment. Otherwise, the commit will be placed in the Other Notable Changes section.

nodejs-github-bot · 2026-07-11T10:05:13Z

Commit Queue failed

- Loading data for nodejs/node/pull/64389
✔ Done loading data for nodejs/node/pull/64389
----------------------------------- PR info ------------------------------------
Title test_runner: add `context.log()` and `test:log` event (#64389)
Author Moshe Atlow <moshe@atlow.co.il> (@MoLow)
Branch MoLow:test-runner-log -> nodejs:main
Labels semver-minor, lib / src, notable-change, author ready, needs-ci
Commits 1
- test_runner: add context.log() and test:log event
Committers 1
- Moshe Atlow <moshe@atlow.co.il>
PR-URL: https://github.com/nodejs/node/pull/64389
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Chemi Atlow <chemi@atlow.co.il>
------------------------------ Generated metadata ------------------------------
PR-URL: https://github.com/nodejs/node/pull/64389
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Chemi Atlow <chemi@atlow.co.il>
--------------------------------------------------------------------------------
ℹ This PR was created on Thu, 09 Jul 2026 09:58:25 GMT
✔ Approvals: 2
✔ - Benjamin Gruenbaum (@benjamingr) (TSC): https://github.com/nodejs/node/pull/64389#pullrequestreview-4662895197
✔ - Chemi Atlow (@atlowChemi): https://github.com/nodejs/node/pull/64389#pullrequestreview-4664897612
✔ Last GitHub CI successful
ℹ Last Full PR CI on 2026-07-09T13:47:17Z: https://ci.nodejs.org/job/node-test-pull-request/74690/
- Querying data for job/node-test-pull-request/74690/
✔ Build data downloaded
✔ Last Jenkins CI successful
--------------------------------------------------------------------------------
✔ No git cherry-pick in progress
✔ No git am in progress
✔ No git rebase in progress
--------------------------------------------------------------------------------
- Bringing origin/main up to date...
From https://github.com/nodejs/node
* branch main -> FETCH_HEAD
✔ origin/main is now up-to-date
- Downloading patch for 64389
From https://github.com/nodejs/node
* branch refs/pull/64389/merge -> FETCH_HEAD
✔ Fetched commits as 26079c0cfa62..645ad450751b
--------------------------------------------------------------------------------
Auto-merging doc/api/test.md
CONFLICT (content): Merge conflict in doc/api/test.md
error: could not apply 645ad45075... test_runner: add context.log() and test:log event
hint: After resolving the conflicts, mark them with
hint: "git add/rm <pathspec>", then run
hint: "git cherry-pick --continue".
hint: You can instead skip this commit with "git cherry-pick --skip".
hint: To abort and get back to the state before "git cherry-pick",
hint: run "git cherry-pick --abort".
hint: Disable this message with "git config set advice.mergeConflict false"
✘ Failed to apply patches

https://github.com/nodejs/node/actions/runs/29148679566

Add a log(message[, data]) method to TestContext and SuiteContext that emits a new test:log event. Unlike test:diagnostic, which is buffered so it is emitted in the order tests are defined, test:log is emitted immediately, in the order tests execute, including under process isolation where it bypasses the per-file declaration order buffer. This gives reporters that render the test tree unbuffered a live, attributed logging channel that captured stdout cannot provide under concurrency. The event carries the message, an optional opaque structured payload that the runner passes through untouched, and the emitting test's name, testId, parentId, nesting, and location. Built-in reporters render it the same way they render test:diagnostic. Signed-off-by: Moses Atlow <moshe@atlow.co.il>

nodejs-github-bot · 2026-07-12T07:37:59Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74748/

nodejs-github-bot · 2026-07-12T10:18:56Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74750/

nodejs-github-bot · 2026-07-12T10:53:48Z

CI: https://ci.nodejs.org/job/node-test-pull-request/74751/

nodejs-github-bot · 2026-07-12T11:45:07Z

Landed in 892976d

Add a log(message[, data]) method to TestContext and SuiteContext that emits a new test:log event. Unlike test:diagnostic, which is buffered so it is emitted in the order tests are defined, test:log is emitted immediately, in the order tests execute, including under process isolation where it bypasses the per-file declaration order buffer. This gives reporters that render the test tree unbuffered a live, attributed logging channel that captured stdout cannot provide under concurrency. The event carries the message, an optional opaque structured payload that the runner passes through untouched, and the emitting test's name, testId, parentId, nesting, and location. Built-in reporters render it the same way they render test:diagnostic. Signed-off-by: Moses Atlow <moshe@atlow.co.il> PR-URL: #64389 Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com> Reviewed-By: Chemi Atlow <chemi@atlow.co.il>

Notable changes: ffi: * (SEMVER-MINOR) add getCurrentEventLoop (Paolo Insogna) #64323 test_runner: * (SEMVER-MINOR) add context.log() and test:log event (Moshe Atlow) #64389 * (SEMVER-MINOR) report `entryFile` in `TestStream` events (Moshe Atlow) #64309 PR-URL: #64655

Add a log(message[, data]) method to TestContext and SuiteContext that emits a new test:log event. Unlike test:diagnostic, which is buffered so it is emitted in the order tests are defined, test:log is emitted immediately, in the order tests execute, including under process isolation where it bypasses the per-file declaration order buffer. This gives reporters that render the test tree unbuffered a live, attributed logging channel that captured stdout cannot provide under concurrency. The event carries the message, an optional opaque structured payload that the runner passes through untouched, and the emitting test's name, testId, parentId, nesting, and location. Built-in reporters render it the same way they render test:diagnostic. Signed-off-by: Moses Atlow <moshe@atlow.co.il> PR-URL: #64389 Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com> Reviewed-By: Chemi Atlow <chemi@atlow.co.il>

Notable changes: ffi: * (SEMVER-MINOR) add `getCurrentEventLoop` (Paolo Insogna) #64323 test_runner: * (SEMVER-MINOR) add `context.log()` and `test:log` event (Moshe Atlow) #64389 * (SEMVER-MINOR) report `entryFile` in `TestStream` events (Moshe Atlow) #64309 PR-URL: #64655

Add a log(message[, data]) method to TestContext and SuiteContext that emits a new test:log event. Unlike test:diagnostic, which is buffered so it is emitted in the order tests are defined, test:log is emitted immediately, in the order tests execute, including under process isolation where it bypasses the per-file declaration order buffer. This gives reporters that render the test tree unbuffered a live, attributed logging channel that captured stdout cannot provide under concurrency. The event carries the message, an optional opaque structured payload that the runner passes through untouched, and the emitting test's name, testId, parentId, nesting, and location. Built-in reporters render it the same way they render test:diagnostic. Signed-off-by: Moses Atlow <moshe@atlow.co.il> PR-URL: #64389 Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com> Reviewed-By: Chemi Atlow <chemi@atlow.co.il>

Notable changes: doc: * add MikeMcC399 as collaborator (Mike McCready) #64656 ffi: * (SEMVER-MINOR) add `getCurrentEventLoop` (Paolo Insogna) #64323 test_runner: * (SEMVER-MINOR) add `context.log()` and `test:log` event (Moshe Atlow) #64389 * (SEMVER-MINOR) report `entryFile` in `TestStream` events (Moshe Atlow) #64309 PR-URL: #64655

nodejs-github-bot added lib / src Issues and PRs related to general changes in the lib or src directory. needs-ci PRs that need a full CI run. labels Jul 9, 2026

MoLow force-pushed the test-runner-log branch from 31f363d to 645ad45Compare July 9, 2026 10:03

benjamingr approved these changes Jul 9, 2026
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atlowChemi approved these changes Jul 9, 2026
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Comment threaddoc/api/test.md

MoLow added the commit-queue Add this label to land a pull request using GitHub Actions. label Jul 9, 2026

Renegade334 added semver-minor PRs that contain new features and should be released in the next minor version. notable-change PRs with changes that should be highlighted in changelogs. labels Jul 9, 2026

nodejs-github-bot added commit-queue-failed An error occurred while landing this pull request using GitHub Actions. and removed commit-queue Add this label to land a pull request using GitHub Actions. labels Jul 11, 2026

MoLow force-pushed the test-runner-log branch from 645ad45 to e24d081Compare July 12, 2026 07:24

atlowChemi approved these changes Jul 12, 2026
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nodejs-github-bot removed the commit-queue Add this label to land a pull request using GitHub Actions. label Jul 12, 2026

nodejs-github-bot merged commit 892976d into nodejs:mainJul 12, 2026
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github-actionsBot mentioned this pull request Jul 21, 2026
2026-07-22, Version 26.6.0 (Current) #64655
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MoLow mentioned this pull request Aug 3, 2026
feat!: support test:log for real-time per-test logging MoLow/reporters#272
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test_runner: add `context.log()` and `test:log` event - #64389

test_runner: add `context.log()` and `test:log` event#64389
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