moah0911moah0911/aftermath/skills/test-regression/SKILL.md

test-regression

Skill14 starsChanged 6 days agoMITView on GitHub

Use when a test suite goes green to red after an edit, or a previously passing test starts failing. Diff against last-known-good, isolate the one change, revert just that hunk instead of patching around it. Includes runner-specific failure signatures, subset re-runs, and checkpoint behavior.

1 other project uses a version of this.

Adopted by

Most recently taken up by

hishamkaram/markdown-memorytheir own version, first seen Oct 17, 2026

Other versions1 project uses a version of this.
Word for word · 0
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Edited · 0
None found.
Wrote their own version · 1
hishamkaram/markdown-memory★ 1same name
How matches are found. Word for word: the exact same text. Edited: shares passages with this file (“99% same” means 99% of its five-word phrases also appear here; 10% or more counts). Their own version: similar meaning, or, weakest, the same name. We can’t tell which project had it first. Projects are counted among the 200 most-starred candidates, and mentions are links to the repository we found, up to 50 per site, so both counts are a floor.
In this repository9 other files it gives its agents.
- AGENTS.mdAGENTS.md
- aftermathSkill
- aftermathSkill
- build-failureSkill
- dependency-failureSkill
- destructive-actionSkill
- flaky-testSkill
- merge-conflictSkill
- retry-loopSkill

The file

We split this skill into the rules it gives an agent

6 rules. About 0 are common, 6 are distinctive, and 0 are very specific to this project.

≈0
Common · estimate
Many files like this have a rule of this kind.
≈6
Distinctive · estimate
This author's own choices. Worth a look.
0
Very specific
Tied to their project's names, files or tools. Probably skip.

Common
Distinctive
Very specific

Distinctive:
Stop. No new edits.
line 17
Distinctive:
Never blame the test before the diff is read.
line 41
Distinctive:
After an auto-revert, re-run the failing subset before any new edit.
line 46
Distinctive:
Never patch around a regression with a new guard elsewhere.
line 51
Distinctive:
Never widen the change to "make the test pass".
line 52
Distinctive:
Never claim green from a partial run.
line 53

≈ “Common” is an estimate: at least 1 in 5 of the 350,495 skill files we read have a rule of the same kind, not the same words. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.

Keep what fits and drop the rest. Your version, ready for your agents.

Files

SKILL.md

Test Regression

A green suite just turned red. The edit caused it until proven otherwise.

Steps

Stop. No new edits.
State what broke: which runner, which suite, which tests, what the last edit touched. One line each.
Find last-known-good: last passing run, last commit, or the ultra checkpoint.
git diff against it. Isolate the single hunk that correlates with the failure.
Revert just that hunk (at lite, propose it and wait; at full, ask before the next edit; at ultra with autoRevert: true, the plugin may already have restored it — verify the diff).
Re-run the failing subset only. Green → stand down. Still red → escalate to retry-loop, do not vary the fix blindly.

Runner signatures and subset re-runs

Runner	Failure signature	Re-run the subset
pytest	`FAILED tests/...`, `1 failed`, `Traceback`	`pytest tests/test_auth.py::test_login -q`
Jest / Vitest	`✕`, `1 failed`, `FAIL`	`npx jest auth.spec -t "login"`
Go	`--- FAIL: TestLogin`	`go test ./pkg/auth -run TestLogin -v`
Cargo	`test result: FAILED`, `panicked at`	`cargo test auth::login -- --nocapture`
node:test	`✖`, `fail 1`	`node --test tests/auth.test.js`
Mocha	`1 failing`	`npx mocha tests/auth.spec.js --grep login`
RSpec	`Failures:`, `1 example, 1 failure`	`bundle exec rspec spec/auth_spec.rb:42`
PHPUnit	`FAILURES!`, `Tests: 3, Failures: 1`	`vendor/bin/phpunit --filter testLogin`
Rake / Rails	`Failure:`, `1 failure`	`bin/rails test test/models/auth_test.rb:12`
Gradle / Maven	`BUILD FAILED` / `BUILD FAILURE`	`./gradlew test --tests 'AuthTest'` / `mvn -Dtest=AuthTest test`

Was it already red?

Never blame the test before the diff is read. If the test was already red before your edit, say so with evidence: the prior run log, or stash your change and re-run. Without evidence, assume your edit did it.

Checkpoints

At ultra with autoRevert: true, a green→red transition restores files that still match the agent's edit. Conflicts (manual edits) are left alone and reported.
After an auto-revert, re-run the failing subset before any new edit. A restore is not proof of green.
/aftermath-checkpoint status shows tracked files; restore and clear are manual overrides.

Never

Never patch around a regression with a new guard elsewhere.
Never widen the change to "make the test pass".
Never claim green from a partial run; name the command you ran.

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