testing-practices

A guide to writing unit tests and integration tests that give the same result each time. It covers controlling random data, shared state, and filesystem access.

In plain words
What is it for?
Use it when adding tests for individual functions or for several parts of an application working together, especially when repeatable results matter.
Why use it?
It helps prevent tests from passing or failing because of leftover data, random values, or the machine they run on.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/itlackey/akm/testing-practices
Any agent
npx skills add itlackey/akm --skill testing-practices
Clone the repo
git clone --depth 1 https://github.com/itlackey/akm

Made for: Claude Code, Codex.

Per session 8 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 42 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00008 $0.00042
Opus 5 $0.00004 $0.00021
Sonnet 5 $0.00002 $0.00008
Haiku 4.5 $0.00001 $0.00004

Measured 3d ago against content hash ef68acb48ca9, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

testing-practices scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

tests/fixtures/stashes/curate-golden/skills/testing-practices/SKILL.md · 7 lines

What it actually says

Testing Practices

Write reliable deterministic unit and integration tests. Avoid shared state, seed randomness, and isolate the filesystem so tests are reproducible.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 3d ago First seen · 7 lines · 8 tokens per session scan A ef68acb48ca9

Subscribe to this mod's changes

testing-practices is a skill published in the GitHub repository itlackey/akm (55 stars, last pushed 3d ago), licensed MPL-2.0. It adds 8 tokens to every session and 42 once invoked, about $0.0000 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Related

Other skills, from other repositories