javascript-testing-patterns

A guide to testing JavaScript and TypeScript code with Jest, Vitest, and Testing Library. Tests check whether code behaves as expected; test-driven development means writing those checks before the code.

In plain words
What is it for?
Use it to write tests, set up testing tools, add mocks and test data, or follow test-driven or behavior-driven development practices.
Why use it?
It helps choose suitable checks for individual functions, connected components, and complete user flows, including failures and unusual inputs.

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/norkzyt/claude-code-autopilot/javascript-testing-patterns
Any agent
npx skills add NorkzYT/claude-code-autopilot --skill javascript-testing-patterns
Clone the repo
git clone --depth 1 https://github.com/NorkzYT/claude-code-autopilot

Made for: Claude Code, Codex.

Per session 63 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 6,337 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. Scan, not verified.
Origin unknown 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 $0.00063 $0.06337
Opus 5 $0.00032 $0.03168
Sonnet 5 $0.00013 $0.01267
Haiku 4.5 $0.00006 $0.00634

Measured 2d ago against content hash 5fc959e9123e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

javascript-testing-patterns scanned grade B with 1 finding 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 2d 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.

Sends data to an external URLmediumData exfiltration

A POST to an outside endpoint may be telemetry or may be exfiltration; either way the mod talks to somewhere, and you should know where.

const response = await fetch("https://api.example.com/users", { method: "POST",
.claude/skills/javascript-testing-patterns/SKILL.md · 1,022 lines

The source is not reproduced here

Licensed GPL-3.0

The repository is licensed GPL-3.0, which this catalogue does not treat as permission to reproduce the file. Read it at the source.

Read it on GitHub

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. 2d ago First seen · 1,022 lines · 63 tokens per session scan B 5fc959e9123e

Subscribe to this mod's changes

javascript-testing-patterns is a skill published in the GitHub repository NorkzYT/claude-code-autopilot (2 stars, last pushed 2mo ago), licensed GPL-3.0. It adds 63 tokens to every session and 6,337 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it B with 1 finding (sends data to an external url). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.