mocha-skill

Q: How do I install mocha-skill?

Run npx skills add https://github.com/lambdatest/agent-skills --skill mocha-skill in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/mocha-skill/ (personal) or .claude/skills/mocha-skill/ (project).

by lambdatestTesting & QA

Generates Mocha tests in JavaScript with Chai assertions and Sinon mocking. Use when user mentions "Mocha", "Chai", "sinon", "describe/it (not Jest)". Triggers on: "Mocha", "Chai", "sinon", "mocha test".

Installs: 225
Last 24h: —
Trending rank: —
Security: Not audited

Install

Works with every agent the skills CLI supports.

npx skills add https://github.com/lambdatest/agent-skills --skill mocha-skill

01
Install
Run the command in your project. The CLI asks which agents to install for.
02
Describe the task
Ask your agent for something this skill covers. It loads mocha-skill automatically when relevant.
03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.

SKILL.md

The instructions your agent reads when the skill is triggered.

Mocha Testing Skill

Core Patterns

Basic Test with Chai

const { expect } = require('chai');

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

  it('should add two numbers', () => {
    expect(calc.add(2, 3)).to.equal(5);
  });

  it('should throw on divide by zero', () => {
    expect(() => calc.divide(10, 0)).to.throw('Division by zero');
  });
});

Chai Assertions

expect(value).to.equal(5);
expect(arr).to.have.lengthOf(3);
expect(obj).to.have.property('name');
expect(str).to.include('hello');
expect(fn).to.throw(Error);
expect(arr).to.deep.equal([1, 2, 3]);
expect(obj).to.deep.include({ name: 'Alice' });

Sinon Mocking

const sinon = require('sinon');

describe('UserService', () => {
  let sandbox;
  beforeEach(() => { sandbox = sinon.createSandbox(); });
  afterEach(() => { sandbox.restore(); });

  it('fetches user from API', async () => {
    const stub = sandbox.stub(api, 'get').resolves({ name: 'Alice' });
    const user = await userService.getUser(1);
    expect(user.name).to.equal('Alice');
    expect(stub.calledOnce).to.be.true;
  });
});

Async Testing

it('should fetch data', async () => {
  const data = await fetchData();
  expect(data).to.have.property('id');
});

it('callback style', (done) => {
  fetchData((err, data) => {
    expect(err).to.be.null;
    done();
  });
});

Anti-Patterns

Bad	Good	Why
Missing `done()`	Use async/await	Hanging tests
No sandbox	`sinon.createSandbox()`	Stubs leak
Arrow in `describe`	Regular function for `this.timeout()`	Context

Quick Reference

Task	Command
Run all	`npx mocha`
Watch	`npx mocha --watch`
Grep	`npx mocha --grep "login"`
Timeout	`npx mocha --timeout 10000`
Recursive	`npx mocha --recursive`

Setup: `npm install mocha chai sinon --save-dev`

Deep Patterns → `reference/playbook.md`

§	Section	Lines
1	Production Configuration	mocharc, NYC coverage, TypeScript
2	Testing with Chai + Sinon	Stubs, spies, assertions
3	Advanced Sinon Patterns	Fake timers, nock HTTP, sequential
4	Async Patterns	Promise, await, callback, events
5	Hooks & Test Organization	Lifecycle, nesting, grep tags
6	Custom Reporters & Plugins	Reporter class, root hooks
7	Express/API Testing	Supertest integration
8	CI/CD Integration	GitHub Actions, services
9	Debugging Quick-Reference	10 common problems
10	Best Practices Checklist	13 items

FAQ

What does the mocha-skill skill do?

How do I install mocha-skill?

Run npx skills add https://github.com/lambdatest/agent-skills --skill mocha-skill in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/mocha-skill/ (personal) or .claude/skills/mocha-skill/ (project).

Which AI agents can use mocha-skill?

Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.

Is mocha-skill safe to install?

No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.

Who maintains mocha-skill?

It is published by lambdatest in lambdatest/agent-skills. It has 225 recorded installs.

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