backnotprop/pstack · skills/principle-test-behavior-not-implementation/SKILL.md

principle-test-behavior-not-implementation skillA

principle-test-behavior-not-implementation is agent-read markdown (skill) from backnotprop/pstack: Apply when you write, change, or keep a test. Call the code the way its users do and assert the result they observe against a literal expected value. If the test would still pass when every imported function returns undefined, rewrite the assertion or delete the test..

Indexed from public GitHub and served as immutable, content-addressed versions. Install it pinned to an exact SHA-256 with the mdr CLI, and every file is verified against the hash recorded here before it reaches your agent. The deterministic audit below grades the latest version, and the same file always earns the same grade.

How to install

Latest version
mdr add backnotprop/pstack/principle-test-behavior-not-implementation@git:20260914.55bfdc2
Exact content
mdr add backnotprop/pstack/principle-test-behavior-not-implementation@sha256:87e40efe4e486f7e

Pin to a label to follow the author's releases, or to a sha256 to freeze the exact bytes forever. Either way the resolved hash is written to mdr.lock, and mdr install reproduces it on any machine.

Badge

mdr badge

[![mdr](https://markdownregistry.com/badge/art_h4l6k74xvekarg72.svg)](https://markdownregistry.com/a/art_h4l6k74xvekarg72)

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Versions

versioncommittedcommitsizeaudit
git:20260914.55bfdc2 latest2026-09-14 55bfdc2 2,575 BA view

Audit of the latest version

A  17 of 17 checks passed. Deterministic, no model, same answer every run.
  • pass: Frontmatter block present
  • pass: Frontmatter declares a name
  • pass: Frontmatter declares a description
  • pass: Size between 200 bytes and 200 KB (2575 bytes)
  • pass: No zero-width or bidi control characters
  • pass: No instruction hidden inside an HTML comment
  • pass: No link to an exfiltration or paste host
  • pass: No credential-shaped string
  • pass: No instruction to send local credentials anywhere
  • pass: No text hidden with inline styles
  • pass: No prompt-injection phrasing
  • pass: No curl or wget piped into a shell
  • pass: No recursive delete of root, home or parent
  • pass: No instruction to read or print local credentials
  • pass: No base64 blob over 200 characters
  • pass: No link to a raw IP address
  • pass: No script tag

Source

GitHub

backnotprop/pstack · 309 stars · license MIT · pushed 2026-09-14 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_h4l6k74xvekarg72
GET https://markdownregistry.com/api/v1/resolve?ref=backnotprop/pstack/principle-test-behavior-not-implementation
GET https://markdownregistry.com/api/v1/blob/87e40efe4e486f7ea639d2ed1fc0abe6c93b8fd0e89a81218086909d2470a52e