testing-conventions
Skill2 starsChanged 2 months agoMITView on GitHub
Test conventions across this portfolio — regression-test comment format, property-test setup for TS and Python, the financial-math arbitrary settings that were tuned by measurement, and why a failing check may be pinning a defect rather than reporting one. Load before writing tests, adding a regression test to a bug fix, setting up property tests, or when a test disagrees with what you expect.
2 other projects use a version of this.
Adopted by
Most recently taken up by
- kunchenguid/no-mistakestheir own version, first seen Oct 8, 2026
- yend724/agent-skillstheir own version, first seen May 4, 2026
Other versions2 projects use a version of this.
Word for word · 0
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Wrote their own version · 2
- kunchenguid/no-mistakes★ 9.2ksame name
- yend724/agent-skills★ 2same 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 repository11 other files it gives its agents.
- .claude/CLAUDE.mdCLAUDE.md
- CLAUDE.mdCLAUDE.md
- ci-and-branch-protectionSkill
- claude-md-hygieneSkill
- design-critiqueSkill
- design-directionSkill
- design-tellsSkill
- memory-and-plansSkill
- portfolio-conventionsSkill
- python-uvSkill
- scheduled-jobsSkill
The file
We split this skill into the rules it gives an agent
1 rule. About 0 are common, 1 is distinctive, and 0 are very specific to this project.
≈0
Common · estimate
Many files like this have a rule of this kind.
≈1
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: line 42
When a check disagrees with what you expect, read the test's intent before assuming the code is wrong.
≈ “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.
Files
Testing conventions
The rules live in ~/.claude/CLAUDE.md. This skill holds the formats and settings.
Unit and regression
- Unit tests for all logic.
A regression test alongside every bug fix, carrying the commit that fixed it:
// Regression: <commit-hash> — <bug description>The hash makes the test self-documenting: a future reader can pull the fix and the reasoning without archaeology in the test file itself.
Property tests for pure transforms
- TypeScript →
fast-check - Python →
hypothesis - File naming:
foo.property.test.tsalongside the unit tests.
Financial-math arbitraries — settings tuned by measurement
| setting | value | why |
| float arbitraries | noNaN, noDefaultInfinity | otherwise every property fails on degenerate inputs rather than on real ones |
| runs | ≥ 1000 | the default run count does not reach the interesting tail |
| tolerance | 1e-6 | not 1e-10 — measured too tight at scale. Accumulated float error over a long series exceeds 1e-10 legitimately, so the tighter tolerance reports false failures. |
The 1e-10 value looks more rigorous and is the obvious thing to reach for. It was tried and it was wrong. Use 1e-6.
A test can pin a defect — read its intent before "fixing" it
When a check disagrees with what you expect, read the test's intent before assuming the code is wrong. Twice in a single day the test was the one asserting the truth:
test_check_ignores_generic_data_driftasserted "data is synced but not guarded" — the surprising behaviour was the deliberate one, named in the test.- A Python and a TypeScript implementation each pinned the other's answer as correct, so "fixing" either one to match intuition would have broken the pair.
A test whose name states an intent is evidence about the design, not just about the code path.
What a green suite does not cover
Two measured blind spots in this portfolio:
- UI components are not unit-tested by convention. In
my-fitness-app, 1,155 tests passed against a tree that would not build — a deleted module was still imported by two components. Only the build gate caught it. - A route-handler test never runs the middleware. A gated API route can ship 100% broken with a fully green suite. Test the middleware path separately.
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