Agent skill

Jest Skill

by sickn33 in sickn33/agentic-awesome-skills

Generates Jest unit and integration tests in JavaScript or TypeScript.

MITAuto-check passedTesting & QA

Install Jest Skill

skills CLI

$ npx skills add sickn33/agentic-awesome-skills --skill jest-skill -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install sickn33/agentic-awesome-skills jest-skill --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/sickn33/agentic-awesome-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/jest-skill .claude/skills/jest-skill && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "jest-skill" agent skill from https://github.com/sickn33/agentic-awesome-skills/tree/main/skills/jest-skill into .claude/skills/jest-skill/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "jest-skill", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/sickn33/agentic-awesome-skills/tree/main/skills/jest-skill

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add sickn33/agentic-awesome-skills --skill jest-skill -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install sickn33/agentic-awesome-skills jest-skill --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/sickn33/agentic-awesome-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/jest-skill .agents/skills/jest-skill && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "jest-skill" agent skill from https://github.com/sickn33/agentic-awesome-skills/tree/main/skills/jest-skill into .agents/skills/jest-skill/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "jest-skill", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add sickn33/agentic-awesome-skills --skill jest-skill -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install sickn33/agentic-awesome-skills jest-skill --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/sickn33/agentic-awesome-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/jest-skill .cursor/skills/jest-skill && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "jest-skill" agent skill from https://github.com/sickn33/agentic-awesome-skills/tree/main/skills/jest-skill into .cursor/skills/jest-skill/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "jest-skill", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/sickn33/agentic-awesome-skills.git --path skills/jest-skill

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add sickn33/agentic-awesome-skills --skill jest-skill -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install sickn33/agentic-awesome-skills jest-skill --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/sickn33/agentic-awesome-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/jest-skill .gemini/skills/jest-skill && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "jest-skill" agent skill from https://github.com/sickn33/agentic-awesome-skills/tree/main/skills/jest-skill into .gemini/skills/jest-skill/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "jest-skill", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install sickn33/agentic-awesome-skills jest-skill

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add sickn33/agentic-awesome-skills --skill jest-skill -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/sickn33/agentic-awesome-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/jest-skill .github/skills/jest-skill && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "jest-skill" agent skill from https://github.com/sickn33/agentic-awesome-skills/tree/main/skills/jest-skill into .github/skills/jest-skill/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "jest-skill", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add sickn33/agentic-awesome-skills --skill jest-skill -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install sickn33/agentic-awesome-skills jest-skill --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/sickn33/agentic-awesome-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/jest-skill .opencode/skills/jest-skill && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "jest-skill" agent skill from https://github.com/sickn33/agentic-awesome-skills/tree/main/skills/jest-skill into .opencode/skills/jest-skill/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "jest-skill", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: jest-skill
GitHub stars: 47k
Used in: 1 other repo
Token cost: ~1.4k tokens
SKILL.md length: 270 words
Files: 1
Skills in repo: 1,493
Repo updated: Oct 9, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Generates Jest unit and integration tests in JavaScript or TypeScript.

User mentions Jest
SKILL.md covers When to Use, Core Patterns, Quick Reference and Deep Patterns, plus 1 more section
Calls npx
Describe/it/expect

What it does

Jest Skill is an agent skill from sickn33/agentic-awesome-skills. Generates Jest unit and integration tests in JavaScript or TypeScript. Covers mocking, snapshots, async testing, and React component testing. Use when user mentions "Jest", "describe/it/expect", "jest.mock", "toMatchSnapshot".

Its SKILL.md is about 1.4k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Testing & QA, covering Unit testing and React components. It works with Jest, TypeScript and JavaScript. The repository describes itself as: AAS Core is the local, agent-first control plane for complete catalog discovery, agent-owned selection, stack validation, and planning, backed by 2,400+ agentic skills. Includes… The licence is MIT.

When your agent uses it

User mentions Jest
Describe/it/expect
ToMatchSnapshot

Example prompts

“describe/it/expect”
“jest.mock”
“toMatchSnapshot”
“/jest-skill”

Requirements

Node.js

What it can do on your machine

Read from SKILL.md and the folder at commit 680176d. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
- npx
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use npx, which can reach the network depending on how they are called.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Jest Skill loads about 1.4k tokens when it runs. Until then it costs about 59 tokens; SKILL.md has 270 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~59
When it runs · the whole SKILL.md, loaded when a task matches: ~1.4k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from sickn33/agentic-awesome-skills at commit 680176d, republished under its MIT licence (© sickn33). 270 words, ~1,407 tokens.

Download SKILL.mdSave it as .claude/skills/jest-skill/SKILL.md (or your agent's skills folder).

name: jest-skill
description: Generates Jest unit and integration tests in JavaScript or TypeScript. Covers mocking, snapshots, async testing, and React component testing. Use when user mentions "Jest", "describe/it/expect", "jest.mock", "toMatchSnapshot".
risk: critical
source: https://github.com/LambdaTest/agent-skills/tree/main/jest-skill
source_repo: LambdaTest/agent-skills
source_type: community
date_added: 2026-07-01
license: MIT
license_source: https://github.com/LambdaTest/agent-skills/blob/main/LICENSE

Jest Testing Skill

When to Use

Use this skill when you need generates Jest unit and integration tests in JavaScript or TypeScript. Covers mocking, snapshots, async testing, and React component testing. Use when user mentions "Jest", "describe/it/expect", "jest.mock", "toMatchSnapshot". Triggers on: "Jest", "expect().toBe()", "jest.mock",...

Core Patterns

Basic Test

javascript

describe('Calculator', () => {
  let calc;
  beforeEach(() => { calc = new Calculator(); });

  test('adds two numbers', () => {
    expect(calc.add(2, 3)).toBe(5);
  });

  test('throws on division by zero', () => {
    expect(() => calc.divide(10, 0)).toThrow('Division by zero');
  });
});

Matchers

javascript

expect(value).toBe(exact);                 // === strict
expect(value).toEqual(object);             // deep equality
expect(value).toBeTruthy();
expect(value).toBeNull();
expect(value).toBeGreaterThan(3);
expect(value).toBeCloseTo(0.3, 5);
expect(str).toMatch(/regex/);
expect(arr).toContain(item);
expect(arr).toHaveLength(3);
expect(obj).toHaveProperty('name');
expect(obj).toMatchObject({ name: 'Alice' });
expect(() => fn()).toThrow(CustomError);

Mocking

javascript

// Mock function
const mockFn = jest.fn();
mockFn.mockReturnValue(42);
mockFn.mockResolvedValue({ data: 'test' });
expect(mockFn).toHaveBeenCalledWith('arg1');
expect(mockFn).toHaveBeenCalledTimes(1);

// Mock module
jest.mock('./database');
const db = require('./database');
db.getUser.mockResolvedValue({ name: 'Alice' });

// Mock with implementation
jest.mock('./api', () => ({
  fetchUsers: jest.fn().mockResolvedValue([{ name: 'Alice' }]),
}));

// Spy
const spy = jest.spyOn(console, 'log').mockImplementation();
expect(spy).toHaveBeenCalledWith('expected');
spy.mockRestore();

// Fake timers
jest.useFakeTimers();
jest.advanceTimersByTime(1000);
jest.useRealTimers();

Async Testing

javascript

test('fetches users', async () => {
  const users = await fetchUsers();
  expect(users).toHaveLength(3);
});

test('resolves with data', () => {
  return expect(fetchData()).resolves.toEqual({ data: 'value' });
});

test('rejects with error', () => {
  return expect(fetchBadData()).rejects.toThrow('not found');
});

React Component Testing (Testing Library)

javascript

import { render, screen, fireEvent, waitFor } from '@testing-library/react';
import '@testing-library/jest-dom';
import LoginForm from './LoginForm';

test('submits login form', async () => {
  const onSubmit = jest.fn();
  render(<LoginForm onSubmit={onSubmit} />);

  fireEvent.change(screen.getByLabelText('Email'), {
    target: { value: 'user@test.com' },
  });
  fireEvent.change(screen.getByLabelText('Password'), {
    target: { value: 'password123' },
  });
  fireEvent.click(screen.getByRole('button', { name: /login/i }));

  await waitFor(() => {
    expect(onSubmit).toHaveBeenCalledWith({
      email: 'user@test.com', password: 'password123',
    });
  });
});

Snapshot Testing

javascript

test('renders correctly', () => {
  const tree = renderer.create(<Button label="Click" />).toJSON();
  expect(tree).toMatchSnapshot();
});
// Update: jest --updateSnapshot

Anti-Patterns

Bad	Good	Why
`expect(x === y).toBe(true)`	`expect(x).toBe(y)`	Better errors
No `await` on async	Always `await`	Swallows failures
Snapshot everything	Snapshot UI, assert logic	Snapshot fatigue

Quick Reference

Task	Command
Run all	`npx jest`
Watch	`npx jest --watch`
Coverage	`npx jest --coverage`
Update snapshots	`npx jest --updateSnapshot`
Run file	`npx jest tests/calc.test.js`
Single test	`test.only('name', () => {})`

Deep Patterns

For production-grade patterns, see reference/playbook.md:

Section	What's Inside
§1 Production Config	Node + React configs, path aliases, coverage thresholds
§2 Mocking Deep Dive	Module/partial/manual mocks, spies, timers, env vars
§3 Async Patterns	Promises, rejections, event emitters, streams
§4 test.each	Array, tagged template, describe.each for table-driven tests
§5 Custom Matchers	toBeWithinRange, toBeValidEmail, TypeScript declarations
§6 React Testing Library	userEvent, hooks, context providers
§7 Snapshot Testing	Component, inline, property matchers
§8 API Service Testing	Mocked axios, CRUD patterns, error handling
§9 Global Setup	Multi-project config, DB setup/teardown
§10 CI/CD	GitHub Actions with coverage gates
§11 Debugging Table	10 common problems with fixes
§12 Best Practices	15-item production checklist

Limitations

Use this skill only when the task clearly matches its upstream source and local project context.
Verify commands, generated code, dependencies, credentials, and external service behavior before applying changes.
Do not treat examples as a substitute for environment-specific tests, security review, or user approval for destructive or costly actions.

Files

Just SKILL.md in skills/jest-skill of sickn33/agentic-awesome-skills.

Open the folder on GitHubat commit 680176d

Used in 1 other repository

We found 5 copies of this SKILL.md (exact, near-identical or edited) in other folders, from 1 other GitHub owner. This page covers the copy in sickn33/agentic-awesome-skills, which our catalogue first saw on October 7, 2026.

lingxling/awesome-skills-cnantigravity-awesome-skills/skills/jest-skill antigravity-awesome-skills/plugins/agentic-awesome-skills/skills/jest-skill+1 more

Compare with similar skills

Jest Skill next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Jest Skill compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Jest Skill this skillsickn33/agentic-awesome-skills	47k	1 repos	~1.4k	Automated safety check: Pass	MIT	today
Typescript Rulessoftspark/ai-toolkit	179	—	~2.7k	Automated safety check: Notes	Apache-2.0	yesterday
Jest Generatorsecondsky/claude-skills	227	—	~1.1k	Automated safety check: Notes	MIT	11 days ago
React Testinggetsentry/sentry	46k	—	~2.2k	Automated safety check: Pass	Custom licence	today
Javascript Typescript Jestgithub/awesome-copilot	40k	1 repos	~559	Automated safety check: Pass	MIT	today
Jest UnitPramodDutta/qaskills	233	—	~3.8k	Automated safety check: Pass	MIT	5 days ago

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Questions about Jest Skill

What does Jest Skill do?

Generates Jest unit and integration tests in JavaScript or TypeScript. Jest Skill is an agent skill from sickn33/agentic-awesome-skills. Generates Jest unit and integration tests in JavaScript or TypeScript.

When should I use Jest Skill?

Jest Skill fits situations like: user mentions Jest; describe/it/expect; toMatchSnapshot.

How do I install Jest Skill in Claude Code?

Run `npx skills add sickn33/agentic-awesome-skills --skill jest-skill -a claude-code`. Or copy the skill folder (skills/jest-skill in sickn33/agentic-awesome-skills) into .claude/skills/jest-skill in your project. Claude Code loads it when a task matches its description.

How do I install Jest Skill in Codex?

Run `npx skills add sickn33/agentic-awesome-skills --skill jest-skill -a codex`. Or copy the skill folder (skills/jest-skill in sickn33/agentic-awesome-skills) into .agents/skills/jest-skill in your project. Codex loads it when a task matches its description.

Can I use Jest Skill in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add sickn33/agentic-awesome-skills --skill jest-skill -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/jest-skill, .gemini/skills/jest-skill, .github/skills/jest-skill and .opencode/skills/jest-skill in your project.

What does Jest Skill need to run?

Going by SKILL.md and its folder, Jest Skill needs the command-line tools its instructions call (npx). Our summary lists: Node.js.

Does Jest Skill access the network?

SKILL.md contains no URLs. Its commands use npx, which can reach the network depending on how they are called. This is read from the text; nothing was executed.

Is Jest Skill safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Jest Skill use?

Jest Skill is published under the MIT licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Jest Skill use?

About 1.4k tokens (SKILL.md is roughly 5.6k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Jest Skill?

Skills that share tags, products or a category with Jest Skill: Typescript Rules (softspark/ai-toolkit, 179 stars), Jest Generator (secondsky/claude-skills, 227 stars), React Testing (getsentry/sentry, 46k stars) and Javascript Typescript Jest (github/awesome-copilot, 40k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Jest Skill?

sickn33 (a GitHub user) maintains it in sickn33/agentic-awesome-skills, which has 47,379 GitHub stars. The repository holds 1,493 skills in this directory. The repository was last updated on October 9, 2026.

Source: sickn33/agentic-awesome-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Jest Skill

Facts

At a glance

What it does

When your agent uses it

Example prompts

Requirements

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Jest Testing Skill

When to Use

Core Patterns

Basic Test

Matchers

Mocking

Async Testing

React Component Testing (Testing Library)

Snapshot Testing

Anti-Patterns

Quick Reference

Deep Patterns

Limitations

Files

Used in 1 other repository

Compare with similar skills

Similar skills

More from sickn33/agentic-awesome-skills

Related

Questions about Jest Skill