Javascript Unit Testing Frameworks With Code Examples

When a tool is also backed up by a giant like Meta, there’s considerable extra comfort and peace of mind. Vue Testing Library is a set of tools focused on testing components without relying on implementation details. Built with accessibility in mind, its approach also makes refactoring a breeze. Mocha is a JavaScript test framework that is focused on being flexible. Because of this flexibility, it allows you to choose different libraries to fulfill other common features such as spying (e.g., Sinon) and assertions (e.g., Chai).

If you look at the State of JS 2020 survey results, you’ll certainly see other names pop up on the list like Jasmine and Testing Library in particular. That said, it’s essential to think about trends and market adoption when choosing a JavaScript unit testing framework. For most teams, sticking to a widely used framework will make it easier to find support resources and recruit the right talent to the team. Introduced in 2010, Jasmine is an open-source JavaScript testing framework that is capable of testing all types of JavaScript applications. This framework supports Behavioral Driven Development . Using Jasmine, one can perform test cases similar to user behavior on a website.

Install Cypress and write tests locally.

Jest builds on the body of work laid by Jasmine, which uses a behavior-driven development taxonomy where you describe a test suite, make it … should (or expect … to) expectations. Running the automation tests on aBrowserStack real device cloud reduces the time needed to be spent on configuring and maintaining the device infrastructure. This will eventually lead to a robust test framework ensuring better test coverage and a better product for the end-users. You can access 3000+ browser-device combinations offering a wide coverage, allowing you to test end to end under real user conditions. Puppeteer is a Node library that provides a high-level API. This API is used to control Chrome or Chromium over the DevTools protocol.

It comes with the Framework Class Library, a large class library, which enables .NET to provide the interoperability feature. JavaScript is one of the most popular programming languages ​​among application and website developers. It can be defined as a high-level, dynamic, interpreted language used with HTML web applications. It is also used for non-web documents, such as PDF files and desktop widgets. Jasmine happens to be compatible across almost every library or framework of your choice, and this makes it one of the most flexible testing frameworks out there.

The following section provides guidelines on things to keep in mind when evaluating which component testing framework is best for your application. This section aims to provide guidance to navigating the testing ecosystem and choosing the right tools for your Vue application or component library. Mocha runs just fine with the built-in assert module of Node.js , or with any other assertion library such as Chai or Should. Mainly utilized for asynchronous testing, Jasmine happens to be a JavaScript testing framework that is full of innovative features. Running on Node JS allows flexible and accurate bug reporting by running the test cases serially. The different types of testing frameworks have made many individuals confused in the long run.

unit testing frameworks javascript

Jasmine is ranked on #3 for JavaScript testing framework according to stateofjs 2018. Rated as number #1 JavaScript automation testing framework for 2018 by the stateofjs survey. Jest was developed by Facebook and used to test WordPress Developer vs Web Developer: A Detailed Overview JavaScript codes, especially applications developed using React JS. Start up with your free practical React Redux testing. Part of the popularity of Jest is that it covers a lot of prevalent technologies and frameworks.

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It creates test Globals (keywords like “describe” or “test”) by default, so that you don’t have to import them in your tests. If you want flexible configuration, including your preferred libraries, then the additional set-up and PHP hosting for your website configuration of Mocha is something you definitely need to check out. Jest improves with every update, and as mentioned before, has the most active community, which helps you reach solutions fast when you’re most in need.

Needs to review the security of your connection before proceeding. By default, Cypress does not support multiple-browser instances or control more than one open browser simultaneously. Cypress will never have support for handling multiple browser tabs. You can control the entire workflow directly from your IDE or CMD. You only need to save a file and the framework will run the test cases for you. LambdaTest integrates with numerous CI/CD tools such as Jenkins, CircleCI and more to help you pace your release pipelines.

Jasmine is a popular testing framework which is famously used as a behavior-driven development tool. BDD involves writing tests before you write the actual code (as opposed to Test driven development ). It’s DOM-less, which means it does not rely on browsers to run. Unlike other JS testing frameworks, Storybook is more of a UI testing tool. It provides an isolated environment for testing components.

  • The List reporter outputs a simple specifications list as test cases pass or fail, outputting the failure details at the bottom of the output.
  • You will also need to have yarn or npm installed in your system.
  • If a file matching the given glob changes or is added or removed mocha will rerun all tests.
  • With this transition, comes the need for excellent testing tools too.
  • TestCafe is a great alternative to Selenium-Based tools.

In other words, if you are using the tdd interface, suiteSetup maps to beforeAll, and setup maps to beforeEach. Each process launched by parallel mode is assigned a unique id, from 0 for the first process to be launched, to N-1 for the Nth process. This worker id may be accessed in tests via the environment variable MOCHA_WORKER_ID. It can be used for example to assign a different database, service port, etc for each test process. Third-party reporters may encounter issues when attempting to access non-existent properties within Test, Suite, and Hook objects. If a third-party reporter does not work in parallel mode , please file an issue.

Tools like mocha and chai can be used to create the necessary testing environment and structure around this library. The library provides special tools for different frameworks like React, Preact, React Native, Marko, Angular, Vue, and Svelte. The most famous of them is React Testing Library which is very widely adopted. Sometimes the quick and effective unit and integration tests are not enough.


When a test file is loaded, Mocha executes all of its suites and finds–but does not execute–any hooks and tests therein. Mocha has been around for quite a while; it was initially released in November 2011. However, unlike other frameworks like Jest and Jasmine, it relies on third-party assertions, mocking, and spying tools like Sinon and Chai. It is very extensible and has a lot of plugins, extensions, and libraries designed to run on top of it. According to “The State of JavaScript 2021,” the most popular JavaScript testing frameworks and libraries in 2021 were Testing Library, Vitest, Jest, Cypress, Playwright, and Storybook.

  • It’s actually a fork of an earlier project, Puppeteer .
  • In other words, jsdom simulates a browser’s environment without running anything but plain JS.
  • To maintain backwards compatibility, run your root hooks if and only if global.beforeEach exists.
  • The framework is open source and supported by a community, you will not get an instant solution to any of your problems.

Cypress is also a JavaScript testing framework that is favored for React projects, but is also more broadly applicable across other JavaScript frameworks like Angular and Node. Just thinking about it makes many people want to slow down and reduce the pace of code updates, which is exactly the opposite of what most software teams need to achieve. How often have you seen a desire to introduce more benefits and improvements into the software projects as quickly as possible?

Where can I test JavaScript code?

Jest aims to work out of the box, config free, on most JavaScript projects. Here are some of the tools and services to help your business grow. The primary factor to choose Karma lies in its support to integrate with CI/CD engines and the following features. Vitest supports both Typescript and JSX out of the box. AVA doesn’t create any Globals for you, so you can control more easily what you use.

The dream of every JavaScript developer is to create a bug-free web app. You can start your journey on the path of a bug-free code by unit testing your components. Well, Storybook makes unit testing easier by helping you to create independent components.

If you are proficient in JavaScript and are looking for a tool that can perform automation testing on a local machine, you should check out Cypress. To sum up, if your web application is built using modern JavaScript frameworks like React, Angular, etc. and cross browser testing is not of high priority, Cypress might suit the bill. It has a simple API while still supporting advanced features.

Depending on the number and nature of your tests, you may find a significant performance benefit when running tests in parallel (using the –parallel flag). The mocha executable supports all applicable flags which the node executable supports. By default all files in the current directory having one of the extensions provided by –extension and not contained in the node_modules or .git folders are watched.

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