testing-checklist

testing-checklist is a skill for Claude Code from yuri-semenenko/ai-engineering-workspace. It costs 133 tokens per session (1,551 once invoked), scanned A, original, MIT.

A practical checklist for deciding what to test and how to write tests, including TDD, which means writing a failing test before the code and then making it pass.

In plain words
What is it for?
Use it when adding features, fixing bugs, reviewing tests, or choosing between unit, integration, and browser-level tests in projects using Vitest or React Testing Library.
Why use it?
It helps catch the behavior that matters without chasing coverage numbers or filling the codebase with brittle, low-value tests.

Skill for Claude Code

Written for Claude Code: installed under .claude/. Also seen: mentions subagents.

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/yuri-semenenko/ai-engineering-workspace/testing-checklist
Any agent
npx skills add yuri-semenenko/ai-engineering-workspace --skill testing-checklist
Clone the repo
git clone --depth 1 https://github.com/yuri-semenenko/ai-engineering-workspace

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for testing-checklist

README.md
[![agentmods](https://agentmods.dev/badge/skills/yuri-semenenko/ai-engineering-workspace/testing-checklist.svg)](https://agentmods.dev/skills/yuri-semenenko/ai-engineering-workspace/testing-checklist)
Your own site
<a href="https://agentmods.dev/skills/yuri-semenenko/ai-engineering-workspace/testing-checklist"><img src="https://agentmods.dev/badge/skills/yuri-semenenko/ai-engineering-workspace/testing-checklist.svg" alt="Measured on agentmods" height="20"></a>
Per session 133 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,551 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 5.1 $0.00133 $0.01551
Opus 5 $0.00067 $0.00776
Sonnet 5 $0.00027 $0.00310
Haiku 4.5 $0.00013 $0.00155

Measured 6d ago against content hash 145dbcb57549, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

testing-checklist 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 6d 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.

claude-code/.claude/skills/testing-checklist/SKILL.md · 82 lines

How it starts

The opening of the file, as written. The whole thing — 82 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Testing Checklist

A pragmatic checklist for writing and reviewing tests. Read the relevant section for the change at hand rather than the whole file. Tests are the executable spec — optimize them for reading, not for coverage numbers.

Rationalizations (read first)

Rationalization Rebuttal
"I'll add tests later." Later is the load-bearing word — it rarely arrives. The test is part of the change, not a follow-up.
"Tests pass, ship it." Passing tests are evidence, not proof. They only cover what they assert — check what they don't cover.
"This code is too simple to break." Simple code with branch logic breaks at the boundaries. Test the boundaries, skip the trivial middle.
"Coverage is at N%, we're good." Coverage measures execution, not assertion. A test with no meaningful assert inflates N and catches nothing.
"The bug is fixed, no test needed." A fix without a regression test is a bug on a return ticket. Red first, then green.
"I'll write the code first, then add tests." Test-after validates the code you happened to write, not the behavior you wanted. Red first keeps the test honest.
"I'll DRY up these tests with helpers." Test code is spec, not production code. DAMP wins: some duplication beats indirection the reader must unfold.

What to test (in priority order)

  • Branch logic — every non-trivial if/switch/early-return path, especially error paths.
  • Boundaries — empty input, one item, max size, null/undefined, zero, negative, off-by-one edges.
  • Contracts — what callers rely on: return shapes, thrown error types, emitted events, side effects.
  • Error handling — the failure path is production code too; assert what happens when the dependency fails.
  • Regressions — every fixed bug gets a test that fails without the fix (write it first, watch it fail).

What NOT to test

  • Implementation details — private helpers, internal state, call order that a refactor may change. Test through the public surface.
  • The framework — React rendering, ORM query building, library internals. Assume they work; test your logic.
  • Trivial pass-throughs — getters, re-exports, config objects with no logic.
  • Exact copies of the implementation — a test that mirrors the code's algorithm proves nothing; assert on known input → expected output instead.

Read the full file on GitHub · 82 lines

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. 6d ago First seen · 82 lines · 133 tokens per session scan A 145dbcb57549

Subscribe to this mod's changes

testing-checklist is a skill published in the GitHub repository yuri-semenenko/ai-engineering-workspace (1 stars, last pushed 5d ago), licensed MIT. It adds 133 tokens to every session and 1,551 once invoked, about $0.0007 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 2026-08-31.

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