mocha

What is mocha?

Mocha is a feature-rich JavaScript test framework running on Node.js and in the browser, making asynchronous testing simple and fun. Mocha tests run serially, allowing for flexible and accurate reporting, while mapping uncaught exceptions to the correct test cases.

What are mocha's main functionalities?

Test Organization

Organize tests in suites and sub-suites using describe() and context(), and specify test cases using it().

"use strict";\nconst assert = require('assert');\ndescribe('Array', function() {\n  describe('#indexOf()', function() {\n    it('should return -1 when the value is not present', function() {\n      assert.equal([1, 2, 3].indexOf(4), -1);\n    });\n  });\n});

Asynchronous Testing

Support for testing asynchronous code with ease, using callbacks, promises, or async/await.

"use strict";\nconst assert = require('assert');\ndescribe('User', function() {\n  describe('#save()', function() {\n    it('should save without error', function(done) {\n      const user = new User('Luna');\n      user.save(function(err) {\n        if (err) done(err);\n        else done();\n      });\n    });\n  });\n});

Hooks

Lifecycle hooks such as before(), after(), beforeEach(), and afterEach() for setting up preconditions and clean-up after tests.

"use strict";\ndescribe('Connection', function() {\n  before(function() {\n    // runs once before the first test in this block\n  });\n\n  after(function() {\n    // runs once after the last test in this block\n  });\n\n  beforeEach(function() {\n    // runs before each test in this block\n  });\n\n  afterEach(function() {\n    // runs after each test in this block\n  });\n\n  // test cases\n});

Other packages similar to mocha

jest

Jest is a delightful JavaScript Testing Framework with a focus on simplicity. It works out of the box for any React project and is often compared to Mocha for its comprehensive feature set including a built-in assertion library and mock functions.

jasmine

Jasmine is a behavior-driven development framework for testing JavaScript code. It does not rely on browsers, DOM, or any JavaScript framework. Thus, it's suited for websites, Node.js projects, or anywhere that JavaScript can run. It's compared to Mocha for its clean syntax and testing capabilities.

ava

AVA is a test runner for Node.js with a concise API, detailed error output, and process isolation that lets you develop with confidence. It is often compared to Mocha for its modern, concurrent testing features, but differs in its approach to running tests in parallel by default.

README

☕️ Simple, flexible, fun JavaScript test framework for Node.js & The Browser ☕️

Links

• Documentation
• Release Notes / History / Changes
• Code of Conduct
• Contributing
• Gitter Chatroom (ask questions here!)
• Issue Tracker

Backers

Become a backer and show your support to our open source project on our site.

Sponsors

Does your company use Mocha? Ask your manager or marketing team if your company would be interested in supporting our project. Support will allow the maintainers to dedicate more time for maintenance and new features for everyone. Also, your company's logo will show on GitHub and on our site - who doesn't want a little extra exposure? Here's the info.

Development

You might want to know that:

• Mocha is one of the most-depended-upon modules on npm (source: libraries.io), and
• Mocha is an independent open-source project, maintained exclusively by volunteers.

You might want to help:

• New to contributing to Mocha? Check out this list of good first issues
• Mocha could use a hand with these issues
• The maintainer's handbook explains how things get done

Finally, come chat with the maintainers on Gitter if you want to help with:

• Triaging issues, answering questions
• Review, merging, and closing pull requests
• Other project-maintenance-y things

License

Copyright 2011-2021 OpenJS Foundation and contributors. Licensed MIT.

Changelog

8.4.0 / 2021-05-07

:tada: Enhancements

• #4502: CLI file parsing errors now have error codes (@evaline-ju)

:bug: Fixes

• #4614: Watch: fix crash when reloading files (@outsideris)

:book: Documentation

• #4630: Add options.require to Mocha constructor for root hook plugins on parallel runs (@juergba)
• #4617: Dynamically generating tests with top-level await and ESM test files (@juergba)
• #4608: Update default file extensions (@outsideris)

Also thanks to @outsideris for various improvements on our GH actions workflows.