Overview

Mocha

Stacks8.9K

Followers3.0K

Votes430

Karma

Stacks2.6K

Followers603

Votes181

GitHub Stars12.0K

Forks1.7K

Karma vs Mocha: What are the differences?

Introduction

Here, we will present the key differences between Karma and Mocha, two popular JavaScript testing frameworks.

Test Runner and Browser Integration: Karma acts as a test runner and provides seamless browser integration, allowing you to run tests on multiple browsers simultaneously. Mocha, on the other hand, is a test framework, but it doesn't have built-in support for browser automation and requires additional tools like WebDriver for running tests in different browsers.
Testing Styles:
- Karma primarily focuses on running tests written in various testing frameworks like Mocha, Jasmine, or QUnit, providing a test runner for these frameworks to execute tests in a browser environment.
- Mocha is a more comprehensive testing framework that provides a syntax for writing tests, assertion libraries, and supports different styles of testing like BDD (Behavior-Driven Development) and TDD (Test-Driven Development) out of the box.
Parallel Execution: Karma allows parallel execution of tests across multiple browsers, improving test execution time for large test suites. Mocha, however, doesn't offer parallel execution by default and will run tests sequentially.
Code Coverage: Karma includes built-in code coverage reports, which can be generated during test execution, giving insights into the percentage of code covered by tests. Mocha itself doesn't provide code coverage functionality, but it can be integrated with other tools like Istanbul to generate code coverage reports.
Browser Refresh: Karma has a live-reload feature that automatically refreshes the browsers whenever the test or source code changes. Mocha doesn't have this functionality, requiring you to manually refresh the browser or use additional tools like nodemon.
Integration with Task Runners: Karma integrates well with task runners like Grunt or Gulp, allowing you to automate test execution along with other development tasks. Mocha, being a test framework, can also be integrated with task runners, but it requires additional configuration and setup.

In summary, Karma offers browser integration, parallel execution, code coverage, automatic browser refresh, and seamless integration with task runners. On the other hand, Mocha provides a comprehensive testing framework with different testing styles and can be integrated with Karma for browser testing.

Advice on Mocha, Karma

Abigail

Dec 10, 2019

Decided

We use Mocha for our FDA verification testing. It's integrated into Meteor, our upstream web application framework. We like how battle tested it is, its' syntax, its' options of reporters, and countless other features. Most everybody can agree on mocha, and that gets us half-way through our FDA verification and validation (V&V) testing strategy.

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Comments

Detailed Comparison

Mocha	Karma
Mocha is a feature-rich JavaScript test framework running on node.js and 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.	Karma is not a testing framework, nor an assertion library. Karma just launches a HTTP server, and generates the test runner HTML file you probably already know from your favourite testing framework. So for testing purposes you can use pretty much anything you like.
browser support;simple async support, including promises;test coverage reporting;string diff support;javascript API for running tests;proper exit status for CI support etc;auto-detects and disables coloring for non-ttys;maps uncaught exceptions to the correct test case;async test timeout support;test-specific timeouts;growl notification support;reports test durations;highlights slow tests;file watcher support;global variable leak detection	Test on Real Devices;Remote Control;Testing Framework Agnostic;Open Source;Easy Debugging;Continuous Integration
Statistics
GitHub Stars -	GitHub Stars 12.0K
GitHub Forks -	GitHub Forks 1.7K
Stacks 8.9K	Stacks 2.6K
Followers 3.0K	Followers 603
Votes 430	Votes 181
Pros & Cons
Pros 137 Open source 102 Simple 81 Promise support 48 Flexible 29 Easy to add support for Generators Cons 3 Cannot test a promisified functions without assertion 2 No assertion count in results 1 Not as many reporter options as Jest	Pros 61 Test Runner 35 Open source 27 Continuous Integration 22 Great for running tests 18 Test on Real Devices Cons 1 Slow, because tests are run in a real browser 1 Requires the use of hacks to find tests dynamically
Integrations
No integrations available	Jasmine

What are some alternatives to Mocha, Karma?

BrowserStack

BrowserStack is the leading test platform built for developers & QAs to expand test coverage, scale & optimize testing with cross-browser, real device cloud, accessibility, visual testing, test management, and test observability.

Selenium

Selenium automates browsers. That's it! What you do with that power is entirely up to you. Primarily, it is for automating web applications for testing purposes, but is certainly not limited to just that. Boring web-based administration tasks can (and should!) also be automated as well.

Sauce Labs

Cloud-based automated testing platform enables developers and QEs to perform functional, JavaScript unit, and manual tests with Selenium or Appium on web and mobile apps. Videos and screenshots for easy debugging. Secure and CI-ready.

LambdaTest

LambdaTest platform provides secure, scalable and insightful test orchestration for website, and mobile app testing. Customers at different points in their DevOps lifecycle can leverage Automation and/or Manual testing on LambdaTest.

Jasmine

Jasmine is a Behavior Driven Development testing framework for JavaScript. 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.

Jest

Jest provides you with multiple layers on top of Jasmine.

Cypress

Cypress is a front end automated testing application created for the modern web. Cypress is built on a new architecture and runs in the same run-loop as the application being tested. As a result Cypress provides better, faster, and more reliable testing for anything that runs in a browser. Cypress works on any front-end framework or website.

Playwright

It is a Node library to automate the Chromium, WebKit and Firefox browsers with a single API. It enables cross-browser web automation that is ever-green, capable, reliable and fast.

Rainforest QA

Rainforest gives you the reliability of a QA team and the speed of automation, without the hassle of managing a team or the pain of writing automated tests.

CodeceptJS

It is a modern end to end testing framework with a special BDD-style syntax. The test is written as a linear scenario of user's action on a site. Each test is described inside a Scenario function with I object passed into it.