In the past years, JavaScript and its frameworks have gained a lot of popularity. These tools, and many accompanying libraries, have been developed to offer a complete solution for building complex front-end web applications.

The more complex the solutions are, the more we see an increased need for automated processes in the full lifecycle of development. One major part of the lifecycle is automated testing, so today we are going to dive into the most popular Javascript testing frameworks.

A testing framework is simply a set of prewritten tools that helps to support or provide automated testing of an application or its parts. A testing framework should provide:

• Rules or conventions for writing test cases and organizing them into test suites
• Means to automatically execute and self-grade the tests
• Results of the tests that are displayed, formatted, and practical

Let's see an overview of a few of the most popular and widely used JS testing frameworks. We'll list their functionalities and pros and cons, and we'll help you understand them, in order to decide which one would be the best for your project.

MochaJS

MochaJS runs on Node.js and provides support for both front-end and back-end testing. Since it has existed for more than 10 years, it has solid documentation, a wide community, and a lot of online tutorials for easier learning and understanding.

This framework makes asynchronous testing simple by running tests in parallel. That enables accurate reporting and, at the same time, mapping of uncaught exceptions to the correct test cases.

Some of its other benefits include:

• Support for all modern browsers
• Both back-end and front-end testing
• It is open source, which makes it very flexible

• NodeJS debugger is supported which makes error tracing easier

  However, there are also a few cons to consider for this framework:

• Mocha could improve its developer tooling

• It has significantly reduced popularity among the tester community, with the arrival of newer frameworks
• It could do better in terms of overall performance, and onboard features
• Requires a bit more time to set up and configure

Jasmine

Jasmine is a JavaScript BDD (behavior-driven development) test framework, which means it is used to simulate user behavior on a website. It includes both visibility testing as well as responsiveness testing of UI across various devices with different resolutions.

Some other pros of Jasmine include:

• Small, clean, and straightforward syntax
• Strong documentation and community support
• Smooth learning curve
• Good for large projects

When it comes to its downsides, you should consider:

• It needs a lot of configuration, and you need to specify a mocking framework or an assertion library explicitly
• Hard to integrate the snapshot testing by using the jasmine-snapshot library

Karma

Karma is an open-source productive testing environment. It allows a QA to perform tests for an application in different environments.

Karma provides an environment for developers where no configuration setup is needed. Instead, they can just run the tests and get instant feedback. This framework also provides testing on real browsers and devices like phones and tablets.

Some of its other pros include:

• You can control the entire workflow directly from your IDE or CMD
• You can describe tests with popular frameworks like Mocha, Jasmine, and also write a simple adapter for a specific framework
• Supports continuous integration and deployment (CI/CD) using Jenkins, Semaphore or Travis
• Big community

When it comes to cons, there are not any significant ones to consider, and that is why Karma is considered to be one of the best testing frameworks for JavaScript.

Selenium WebDriver

Selenium WebDriver is the most widely accepted testing framework for web applications. It can be used for performing automated cross-browser testing in a thorough manner. It is also open-source, and can be also used for programming languages other than JavaScript.

Some of the main pros for Selenium include:

• The IDE is open source, so it can be easily learned and improved upon by new and inexperienced testers
• It has been around for a long time, so it has a big community and a lot of documentation
• It has its own language, but it also offers language bindings to support coding in Java, JavaScript, PHP, etc.

The pros of Selenium highly outweigh the cons and the fact that it comes free of cost makes it a preferred tool by many organizations. However, these are some of the cons to consider that may help you decide whether it is the right framework for you:

• For getting advantage of the complete features of Selenium, you will require some third-party plugins
• You cannot perform parallel testing with Selenium WebDriver
• The framework is open source and supported by a community, you will not get an instant solution to any of your problems

Pupeteer

Puppeteer is not a framework itself, but a library that can be easily integrated into your solution. It has an API that is used to control Chrome or Chromium over the DevTools protocol. This is perhaps the major downside of Puppeteer since it works only with Chrome and Chromium, and it requires the machine to have them pre-installed.

It can be used for browser-specific applications like page structure tests, taking website screenshots, and more.

Automation scripts written using Puppeteer override the DevTools Protocol API, and it works in a way that it can automatically:

• Launch Chrome (Chromium)
• Open a new tab in the browser
• Navigate to the desired site for testing
• Capture a screenshot and close the browser

Puppeteer allows developers to mock resources, thereby avoiding reliability, consistency, and speed issues. You can manipulate external resources like CSS selectors to make your specific test case execute faster.

One Pager Cheat Sheet

• JavaScript and its frameworks have become increasingly popular and have necessitated the need for automated processes, such as automated testing, to support the full lifecycle of development, which is provided by a testing framework that offers rules, conventions and self-grading tools.
• MochaJS has a wide community, provides support for both front-end and back-end testing, runs tests in parallel for simple asynchronous testing and has both benefits and downsides to consider.
• MochaJS is a versatile testing framework for back-end and front-end code, which can be easily integrated with existing testing frameworks like Jest and Karma.
• Jasmine is a JavaScript BDD testing framework used to simulate and test user behavior, with a small, clean syntax, strong documentation and community support, and a smooth learning curve, though it needs a lot of configuration and lacks built-in snapshot testing.
• Jasmine requires substantial configuration, including integrating an assertion and mocking framework, as well as a snapshot testing library, making it a time-consuming and challenging set up process.
• Karma is an open-source productive testing environment which eliminates the need for configuration setup, supports tests on real browsers and devices, and offers advantages like control over the workflow, adaptability, compatibility with CI/CD, and an active community.
• Karma is an attractive option for developers and QA teams, with its easy setup, real device and browser testing, as well as CI/CD support and large community.
• Selenium WebDriver is an open-source, widely accepted testing framework for web applications, with language bindings for various programming languages and a large community providing support.
• Open-source testing framework Selenium WebDriver is a widely used, free tool that supports multiple programming languages and provides advantages like a large community and documentation for support.
• With Puppeteer, developers can automate certain web browser activities, use a library to control Chrome or Chromium over the DevTools protocol, manipulate external resources to improve test performance, and more.
• Puppeteer only works with Chrome or Chromium as it uses the DevTools Protocol as a connection interface.