The Top 3 JavaScript Testing frameworks

JEST vs Cypress vs Mocha — Software testing is a must for improving the correctness and quality of the code.

Charuka E Bandara
Nov 26, 2020 · 7 min read
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Photo by Fotis Fotopoulos on Unsplash

A few times back software testing frameworks were just limited to one programming language or maybe two. But right now testings are doing in a lot of programming languages like Java, Visual basic script, C#, and JavaScript, etc.

In modern-day development, JavaScript plays a significant role. Many industrial giants use JavaScript Development and testing frameworks for their software implementations. Since this much usage, the number of JavaScript frameworks such as Angular, React, Vue, svelte, and the quality of them is growing day by day. Because of that, the usage of JavaScript testing frameworks such as Jest, Jasmine, Karma, etc. is getting improved and more useable than ever.

What is testing?

If we discuss in one sentence, software testing could be a method, to gauge the practicality of a software system application with associate intent to seek whether the developed software system met the required needs or not and to spot the defects to confirm that the merchandise is defect-free to supply a top-quality product. Nowadays there are many software testing frameworks to make the developer's life easier.

What is a testing framework?

A testing framework could be a set of tips or rules used for making and planning test cases. A framework comprises a mixture of practices and tools that square measure designed to assist QA professionals to check additional with efficiency.

These tests might embrace writing standards, test-data handling strategies, object repositories, processes for storing check results, or info on a way to access external resources.

Three common types of tests

Unit Testing

Unit testing is the most commonly used testing method. It focuses on the smallest unit of software design, usually writing and testing by the developer himself. What mainly focus on this method are incorrect package installations, issues in loops, conditions, statements, etc, and issues in functionalities and arithmetics. Below code, the fragment is an example unit test.

for (var i = 0, l = items.length; i < l; i++) {
(function(n) {
var item = items[n];
var desc = 'should turn `' + item.passed + '` into `' + item.expected + '`';
it(desc, function (done) {
tester(item.passed, item.expected, done);
});
})(i);
}

Integration testing

Integration testing is one of the most popular testing methods in the software industry. It is processing across several units to achieve test goals and find defects. Mainly there are two types of testing mechanisms which are black-box testing and white-box testing.

Black-box testing uses mostly for validations while ignoring the internal working mechanism of the software.

White-box testing uses mostly for verification while concerning the internal working mechanism of the software.

const testButton = document.getElementById(‘test-button’);testButton.click(); drone.ifClickTestButton() .then(isButtonChange => assert(isButtonChange));

End to End Testing

This is the most popular method among almost all tech companies for software testing. Here we do testing according to the black-box testing approach.

Go to URL “https://localhost:4200"
Click on "SignUp"
Expected page URL “https://localhost:4200/sign-up"
Type 'new-user' in the #user_name field
Type 'new-password' in the #password field
Click "SignUp"
Expected page URL “https://localhost:4200/user-profile"

To have an obvious idea about testing types and the advantages of testing, I recommend reading the following article.

03 Popular JavaScript testing Frameworks

01. JEST

It is a JavaScript testing framework that is developed and maintained by Facebook. Jest is popular among the community because of the simplicity and its support for popular JavaScript frameworks like Angular, React, Vue, NodeJS, and also with Babel.

Installing Jest and use it in your code is as easy as you think.

//using yarn
yarn add — dev jest
//using npm
npm install --save-dev jest

After the installation, you need to add jest to your package.json

"scripts": {
"test": "jest"
}

According to the stats of stateofJS we can see that the popularity and usage of the framework are at its hype.

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Source: https://2019.stateofjs.com/testing/jest/

Pros of Jest

  • Almost zero configurations need for any of the JavaScript Frameworks.
  • Tests are running n an isolated manner, which means parallel to each test. So, performing the framework is optimized and enhanced.
  • Jest is a well documented and organized framework that has a rich tool kit with it.
  • It has complete code coverage. Testers can generate code coverage by adding the flag --coverage.
yarn jest --coverage
// will give you passed test Suites and failed Test suites
  • Jest uses a custom resolver for imports in user’s tests, by making it simple to mock any object outside of the developer’s test’s scope.
  • Exception handling is better with its own contexts such as toBe, toBeCloseTo, toEqual, toStrictEqual, toHaveProperty, toMatchSnapshot and toThrowError.
expect(received).toStrictEqual(expect)
//here expected and recieved results will be displayed
- Expected - 0
+ Recieved + 1

Cons of Jest

  • Jest snapshots are efficient only when the code base is small and when reading them from top to bottom. So, you need to reduce the length of the snapshot.

02. Cypress

Cypress a quick, effortless, and dependable tool for testing modern frontend web applications. It aims to overcome the many issues that the engineers and developers face while testing web applications, especially based on React and AngularJS.

Installing Cypress on Linux is not as simple as installing Jest. They have a desktop application which supports the following requirements :

  • macOS 10.9 and above (64-bit only)
  • Linux Ubuntu 12.04 and above, Fedora 21 and Debian 8 (64-bit only)
  • Windows 7 and above

For the Linux operating system, you need to have the required dependencies installed on your system using the following command.

apt-get install libgtk2.0–0 libgtk-3–0 libgbm-dev libnotify-dev libgconf-2–4 libnss3 libxss1 libasound2 libxtst6 xauth xvfb

Then you can install Cypress using the same as yarn or npm.

npm install cypress --save-dev
//or
arn add cypress --dev

Finally, you can open your Cypress project by using yarn or npx.

npx cypress open
//or
yarn run cypress open

According to the stats of stateofJS we can see that the popularity and usage of the framework are neutral during a single year.

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Source: https://2019.stateofjs.com/testing/cypress/

Pros of Cypress

  • It is a developer-friendly open-source all in one testing framework which does not use Selenium.
  • It is a framework that really focuses on end-to-end testing rather than using testing. So, it is not a normal automation framework.
  • They build much of the architecture surrounding Cypress to handle modern JavaScript frameworks well. So, it tests anything which runs on a web browser.
  • Cypress automatically load balances and it can run recorded tests in parallel across multiple virtual machines. You just pass in a --parallel flag.
  • There is a built-in testing library with the support of e2e testing. So, it more flexible with API e2e testing.
  • Testers have the snapshot option, so testers can see what happened before and after each action or command.

Cons of Cypress

  • Cypress has not supported browsers such as IE, Safari, or Opera.
  • Since parallel testing runs on a single machine, it needs more processing power. So, Cypress itself does not recommend this approach.

03. Mocha

Mocha is one of the older, simple, and lightweight JavaScript testing frameworks that runs on NodeJS and the browser, which has over 5 million weekly downloads.

Installing mocha is really simple using npm

npm install --save-dev mocha

Before running any test, you need to change your “scripts” tag in the package.json.

"scripts": {
"test": "mocha"
}

According to the stats of stateofJS we can see that the popularity and usage of the framework are neutral during the last four years. But it increases the interest during the last year.

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Source: https://2019.stateofjs.com/testing/mocha/

Pros of Mocha

  • Supports in any browser or any google chrome base library.
  • Works fine both in frontend and backend.
  • mapping exception for test cases is much easier than other frameworks.
  • Since it comparably older testing framework, there is more support from the community.
  • It has a rich set of plugins and extensions to be used in many unique scenarios.

Cons of Mocha

  • Snapshot testing in mocha is not as easy as other frameworks because you have to deal with a library called chai jest snapshot.
  • To use mocha, we need to have many configurations. So it is easy to use.

Conclusion

With compares to traditional testing approaches, it has a greater advantage to use testing frameworks for automatically look at the code base, which helps to increase a team’s test speed and potency,. Also, for accuracy, it can cut down maintenance prices for specific software and with lower risks.

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Source: https://2019.stateofjs.com/testing/

According to the above survey, we can see that there is a significantly high demand for Jest rather than any other frameworks. We can understand the reason for that by looking at the above-detailed descriptions.

Finally, I would like to recommend that, it is important to use JavaScript testing frameworks for your projects to improve your code correctness and quality.

JavaScript In Plain English

New JavaScript + Web Development articles every day.

Charuka E Bandara

Written by

I am a full-stack software developer and a person who has a passion and love for writing and reading. Email me at ericbandara95@gmail.com

JavaScript In Plain English

New JavaScript + Web Development articles every day.

Charuka E Bandara

Written by

I am a full-stack software developer and a person who has a passion and love for writing and reading. Email me at ericbandara95@gmail.com

JavaScript In Plain English

New JavaScript + Web Development articles every day.

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