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KohulanKohulan/orthonym-skills/skills/test-gate/SKILL.md

test-gate

Skill2 starsChanged 45 days agoMITView on GitHub

Checks that a test fails on some plausible wrong code, such as a guard that always allows or always refuses, an empty result, an identity transform or a missing lock, and gates each new test on four answers: behaviour, regression, owner and seam. Use when writing, changing or reviewing tests: a regression test for a fix, a PR or diff that adds tests, a coverage push, or a green suite that may not catch a bug. Triggers on 'add a test for', 'review these tests', 'is this test enough', fail-closed guards and health checks, locks and concurrency tests, checks that loop over outputs, and mocks or fixtures that already hold the answer. Not for changing an existing expected value (use change-asserted-value) or deriving a property the output must satisfy (use prove-invariant).

7 other projects use a version of this.

Adopted by

Most recently taken up by

The file

We split this skill into the rules it gives an agent

3 rules. 0 are common, 2 are distinctive, and 1 is very specific to this project.

  • 0

    Common

    Most of the 7 edited versions we read keep these.

  • 2

    Distinctive

    This author's own choices. Worth a look.

  • 1

    Very specific

    Tied to their project's names, files or tools. Probably skip.

  • Common
  • Distinctive
  • Very specific
  1. Distinctive:

    Seam: if it needs an export, flag or hook that no production caller uses, test through the real entry point instead and drop the seam.

    line 23
  2. Very specific:

    No assertion, or try/except: pass where pytest.raises belongs.

    line 49
  3. Distinctive:

    Run each wrong version in the copy.

    line 63

“Common” is measured: kept by at least 6 in 10 of the 7 edited versions of this file we could read. “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-gate

The rule

A test earns its place only if some wrong code makes it fail. For every test you write or review, name the cheapest wrong code that a real bug could produce, and check that the test fails on it. If a plausible wrong version still passes, the test is not done.

Gate for a new test

Answer all four before adding it. A blank answer means do not add it yet.

  1. Behaviour: the observable behaviour or contract it protects.
  2. Regression: the credible bug that makes it fail. For a bug fix, run the test on the pre-fix code and watch it fail for that reason.
  3. Owner: why existing tests miss that bug. One contract has one primary test at the strongest boundary; extend a parametrised case before adding a near-duplicate.
  4. Seam: if it needs an export, flag or hook that no production caller uses, test through the real entry point instead and drop the seam.

Wrong code to try

Try each row that applies, in both directions.

Code under testWrong versions the test must fail on
Guard, validator, permission or health checkalways refuses, and always allows
Returns a collectionreturns empty, returns everything
Cache, dedupe, run-onceignores the cache, runs every time
Lock or other concurrency controlno lock, with callers that really overlap (a Barrier and a slow body)
Transform or formatteridentity, a constant
Error pathnothing raised
TTL or timeouta margin smaller than the clock's resolution

A guard is two contracts. "Refuses when unhealthy" also passes on a guard that refuses everything, which is a total outage. A fail-closed check needs a test that the healthy path still gets through. That test is required, not optional.

A check that loops over outputs passes on no output. "Every span is valid" holds for an empty list. Add inputs that must produce output, with exact expected values.

Signs a test cannot fail

  • No assertion, or try/except: pass where pytest.raises belongs.
  • The expected value comes from the code under test, or is imported from it.
  • A mock or fixture already supplies the asserted answer: a backend mock that returns the cached value, or an autouse fixture that pre-seeds state.
  • A "concurrent" test whose callers never overlap.
  • A name that promises more than its input exercises.
  • A helper that exists only for the test.

Review procedure

  1. Copy the tree to a fresh directory of your own (mktemp -d); a shared scratch directory can hold another run's files. Check that the copy's tests import the copy, not an editable install of the real tree (print <pkg>.__file__). Leave the real tree as you found it.
  2. For each test and fixture, pick the wrong versions from the table, in both directions.
  3. Run each wrong version in the copy. A test that still passes on one is not done: fix it and return to this step. "Would fail" counts only after you have seen it fail.
  4. Report one line per test and fixture: keep, change or drop; the wrong versions you ran and whether the test failed on each; the fix, for anything that is not a keep.

Related: prove-invariant for deriving a property the output must satisfy.

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