7 Best Unit Testing Frameworks for Javascript

One of the most popular programming languages used by developers, including test automation engineers, is JavaScript. Over the years, JavaScript has maintained its appeal, and it is unlikely that this will change in the near—or perhaps not so near—future.

Given the high demand for this programming language over the past few years, numerous automation frameworks have emerged to help engineers test JavaScript applications. 

This article aims to help you better understand the best unit testing framework for JavaScript in 2022. 

First, we will look at the advantages and disadvantages of each so you can make a better decision when choosing a framework for your next automated test—and possibly even integrating the test automation framework with a test management tool. 

Let’s begin immediately.

Best Unit Testing Framework For Javascript Tools

#01 Jest

Jest is a popular and one of the best unit testing frameworks for javascript that claims to provide “delightful JavaScript testing,” Jest takes pride in providing a complete and hassle-free experience.

The completeness stems from the fact that, unlike some competitors, Jest does not rely on third-party tools for much of its functionality. Instead, the ease of use is due to Jest’s zero configuration setup. So you can quickly install it and begin writing your first test.

Pros

• It provides a command-line interface for efficiently controlling your tests.
• It includes an interactive mode that runs all affected tests for the code changes you made in your most recent commit.
• With. “only” and. “skip”, you can test a single test or skip tests. This feature comes in handy when debugging individual tests.
• It has excellent documentation, plenty of examples, and a helpful community. You can join the Jest Discord community or ask questions on Stack Overflow.
• Mocking is made easier for developers, as it is one of the most challenging tasks for testing engineers.

Cons

• Auto-mocking causes a slow runtime. While auto-mocking was once thought to be a benefit, it can now be a detriment to testing because it auto-wraps all of your libraries, making your tests run a little slower.

#02 Mocha

Mocha, the second most popular library, is only a test framework that provides developers with the primary test structure. Mocha was initially designed to work with Node.js. 

Still, it now supports a wide range of frameworks, including front-end frameworks like React, Vue, and Angular, as long as you’re willing to get your hands dirty with some configuration.

Pros

• Simple and lightweight. Mocha is a simple solution for smaller projects that do not require sophisticated assertions or testing logic.
• The configuration is adaptable. If you desire flexible configuration, including your preferred libraries, Mocha’s additional setup and configuration is something you should consider.
• Support for the ES module. Mocha allows you to write your tests as ES modules rather than just CommonJS. 

Cons

• More difficult to set up. You must include additional assertions libraries, making it a little more challenging to set up than others. 
• Potential plugin inconsistency. Mocha includes the test structure as globals and saves time by not requiring it in every file. The disadvantage is that plugins may need you to have these anyway, resulting in inconsistencies, which can be frustrating if you’re a perfectionist!
• Documentation is lacking. According to reports, Mocha’s documentation is not its strongest suit.

#03 Cypress

Cypress is again one of the well-known best unit testing frameworks for JavaScript tools we came across while researching for this blog.

Sure like any other technology, Cypress does have a few cons with a ton of pros overall, when you see the big picture, you won’t be able to deny the presence of this tool in the list of best unit testing framework for javascript tools.

Pros

• Cypress is entirely browser-based (Chrome, Firefox, and Edge), with no need for driver binaries.
• Code and application code coexist, giving you complete control over the application under test. Cypress is best known for its E2E (end-to-end) testing capability, which allows you to simulate pre-defined user behaviour, and it reports potential differences each time you deploy new code.
• E2E testing. Cypress can be trusted for end-to-end user testing because it is implemented in a real browser.
• Timeline Snapshot testing. Cypress captures a snapshot of the execution at that precise moment, enabling the QA tester or developer to review what transpired at a specific step.
• Consistent and Reliable Comparatively to other js testing frameworks, Cypress provides a consistent and reliable test execution result.
• Documentation. Cypress has all the information you need to get up to speed, from scratch to run. It also has a thriving neighbourhood.
• Fast. Cypress’s test execution is quick, with a response time of under 20 milliseconds.

Cons

A single browser only. Only one browser can be used to run tests for Cypress.

#04 AVA

AVA is a minimalistic testing runner that takes advantage of JavaScript’s async nature to run tests concurrently, increasing performance.

AVA does not create any Globals for you, giving you more control over what you use. This can add clarity to tests, ensuring that you understand exactly what is happening.

Pros

• Concurrently executing tests 
• Testing is very helpful because it takes advantage of JavaScript’s async nature. 
• The main advantage is reducing the gap between deployments.
• Easy API: Contains a basic API that only offers the features you need
• Snapshot evaluation: Provided by jest-snapshot, which is excellent for notifying you when your application’s user interface (UI) changes unexpectedly.
• Reporter on Tap: By default, Ava displays a report that is readable by humans, but it’s great to get a report in TAP format!

Cons

• No testing in groups: Ava does not allow for the grouping of related tests.
• No internal mockery: Mocking is not included with Ava out of the box, but you can use third-party libraries to do that.

#05 Puppeteer 

The Chrome Development Team created a Node library called Puppeteer, a test execution framework that gives users control over a headless Chrome. The Puppeteer can do everything that can be done manually in a browser.

Most users employ this tool to run various tests on web applications, including: – Creating screenshots and PDFs from web pages – Crawling websites – Automating the testing of chrome extensions, keyboard input simulation, and form submissions.

A puppeteer is a great option for testing the user interface of single-page applications because it is a full-feature-loaded tool. We have also placed it on the list of the best unit testing framework for javascript tools.

Pros

• React Team’s recommendation. The documentation for React contains references and recommendations for using this library.

• Lightweight. Because it was created specifically for testing React apps/components.

• Community. Testing Library has recently gained a lot of traction. Indeed, stackoverflow.com statistics show that the volume of questions about Testing Library has outgrown enzyme.

Cons

• There is no shallow rendering. It doesn’t allow you to “shallowly” render your component without its children, but you can do so by “mocking” features of testing frameworks like Jest.

#06 Karma

Karma is a simple and lightweight open-source JavaScript test runner supported by Google’s Angular.js team and is ideal for testing AngularJS code or any other JavaScript projects. 

Although Node.js is required to run Karma, you are not required to write your code in Node modules. It is simple to run tests locally during development with Karma. The entire workflow can be managed from the command line or an IDE.

Karma is neither a testing framework nor a library of assertions. Instead, it simply launches instances of the web browsers you specify, loads the files you specify, and displays the test results for each browser in the terminal. 

For example, you can use Karma with other testing software. Many popular JavaScript testing suites like Jasmine, Mocha, and QUnit have excellent plugin support.

Pros

• One of the most significant advantages of Karma is the ability to test JavaScript code in multiple real browsers and platforms of your choice, such as desktops, phones, tablets, or a headless PhantomJS instance. Firefox, Chrome and Chrome Canary, Opera, Safari, Internet Explorer, PhantomJS, SauceLabs, BrowserStack, and many other browsers are available.

• Karma’s goal is to create a productive testing environment for developers, so re-running tests when files change is a huge benefit. This tool can be told to monitor all files specified in the configuration file. When changes are made to the file and saved, all of the captured browsers are prompted to run the test code again. Instant feedback from tests makes test writing more efficient and productive.

• Karma is highly configurable and simple to debug. Its tests are capable of being run on a continuous integration server. Karma integrates easily with packages such as Jenkins, Travis, and Semaphore.

Cons

• Because Jest does not run on a real browser (it uses jsdom), it is possible that jsdom will differ from your targeted browser.

• Debugging is less visual than it is in KARMA.

#07 Jasmine

Popular testing framework Jasmine is well-known for being a tool for behaviour-driven development (BDD), and hence, we include it in this list of the best unit testing framework for javascript tools. 

In contrast to test-driven development (TDD), BDD involves writing tests before writing actual code. However, Jasmine can be used by other programming languages, such as Ruby (via Jasmine-gem) or Python (via Jasmin-py). 

In addition to writing JS tests, it has gradually lost some of its appeal. It is DOM-less, so its operation is independent of browsers.

Pros 

• Uncomplicated API. It offers clear, straightforward syntax and a comprehensive and simple API for creating unit tests.
• Includes batteries as well. Jasmine already consists of all the necessary assertion and mocking libraries, so they are not required. 
• So fast. It is fairly quick because it doesn’t rely on any outside libraries.

Cons

• Damaging the environment globally. You don’t need to import test Globals (keywords like “describe” or “test”) because it creates them by default. This might become a drawback in certain circumstances.
• Async testing is difficult; with Jasmine, asynchronous testing functions can be challenging.

Which Javascript Unit Testing Framework Should I Use?

Understand Your Testing Requirements

First and foremost. Do not begin tooling or attempting to solve a problem without determining the problem. 

Each framework you will ever come across can be the best unit testing framework for javascript but understanding the testing requirements and scope of testing is critical; only then should you begin to plan how to build the framework.

I recommend answering the three questions below at the start of this journey and returning to them at various points later on. It can aid in validating that the appropriate areas are being tested and that proper processes for implementation and maintenance are in place.

Which Are The Most Important Areas To Test? 

Before beginning any testing or getting started with any of the best unit testing framework for javascript, decide what you want to concentrate on. First, determine which application features or areas should be tested first.

Create a list of testable scenarios for each feature and decide which level of testing will best satisfy each. Understanding the principles of test automation can be useful for determining the most crucial areas to test and the depths at which to do so.

How Will The Framework Be Implemented And Maintained? 

Make a high-level plan for the framework’s implementation after identifying the owners or stakeholders. Before considering the project’s scope and timeline, consider the steps you must take to establish the framework.

Following implementation, additional tasks will be like maintaining the framework and adding new tests. For example, when tests should be added to the feature development process and any test coverage thresholds you should not cross, they should be discussed with the stakeholders.

This will really help you a lot in selecting the best unit testing framework for javascript to suit your overall project requirements.

Look For The Pros And Cons In Each Framework

My top requirement for a framework is to be simple to use and expand upon.

In terms of documentation and customer support, I’m also curious about how well the framework is supported. It also helps to know whether the framework is actively being developed and whether the tech community as a whole uses it extensively.

Additionally, I’d like to know if the framework is a paid or open-source option. Both kinds are common, but I prefer open-source frameworks whenever I can. Work with management to determine a fair price for a framework if your organization is willing to pay for it.

Hence, you will not just select the best unit testing framework for javascript but also the one best compatible with you.

Make A Choice As A Team

After researching frameworks, weighing the Pros and Cons, and spiking a few options, you should be able to rank each framework on your list. Gather the stakeholders and go over each option.

After the discussion, your team will most likely have identified at least one framework that appears to be the best option. Choose one, detail how to implement the framework in the plan, and then go for it.

Because, at the end, your entire team has to use the best unit testing framework for javascript that you choose to work with.

If no frameworks meet your requirements, consider creating your own. 

This is not the path I would recommend because it is difficult and time-consuming, especially in the beginning. However, if you decide that this is the path for you, you can use this guide to help you succeed.

It is also acceptable to change your mind later. Things shift. Applications evolve. What you choose today might not be the best choice in a year. 

This isn’t ideal, but it’s doable. I’ve worked on projects where we decided to change the test framework only a year after it was implemented and others where we decided to change it after five or more years. 

While making a significant change will take time, it will be worth it in the end.

Test Runners 

Test runners are libraries or tools that launch, execute, and aggregate the results of your tests. JS tests can run in various environments, including a browser, a headless browser, and Node.js. 

All three require different configurations and have different benefits and constraints. Almost all test runners can generate coverage reports, which show how much of your code your unit tests have executed.

Testing frameworks are used to organize tests by providing wireframing that makes them structured and readable.

Testing Frameworks

Testing frameworks are used to organize tests by providing wireframing that makes them structured and readable.

Assertion Libraries

These provide functions for determining the validity of a statement. They are effectively syntactic sugar that saves us from writing a lot of if statements and try/catch statements, making unit tests much more readable.

Double-Check Your Libraries.

These are plugins that hook into assertions and testing frameworks and provide access to test doubles. They are also known as mocking libraries. They are used to isolate the unit to be tested and to simulate various test scenarios.

Conclusion

You should consider the application type being tested, the number of configurations that require support, the requirement for front-end and back-end testing, community support, etc. 

When selecting a JavaScript test automation framework, be sure to consider the benefits and drawbacks of each framework. 

The ideal test automation solution differs from project to project and depends on several variables. Fortunately, TestGrid provides automation solutions that address various project and product requirements. 

To meet all of your testing and quality control requirements,

To learn more about TestGrid, click here.