Jest vs Jasmine: Know Their Pros And Cons


Whether you’re writing JavaScript for the browser or node JS, the question constantly exists that “what unit test library should I use to confirm my javascript code is working as wanted?”  We’ve got some data you probably are eager to know. In this blog, we will learn about jest vs jasmine, jasmine js, and Javascript framework. So let’s begin…

Jasmine js

Jasmine is simpler to get started, it was created to be easy to set up and utilize in approximately any scenario. It needs a runner, such as Karma, in maximum scenarios, but few distros have one baked in. Jasmine is the greatly widely utilized test framework for those people who do testing in AngularJS. 

So, if you use AngularJS it should be perhaps among the first options. Besides, it functions pretty well in most scenarios you might require, asynchronous code being the central issue area. Moreover, it is an open-source JavaScript framework with the capacity of testing any type of JavaScript application. By following the Behavior Driven Development (BDD) method, Jasmine gives a small syntax to test the smallest unit of the whole application rather than testing it as an entirety.

Pros:

  1. Easy setup through jasmine-node.
  2. Headless running out of the box.
  3. The polished syntax for built-in assertions can be broadened with some other assertion libraries.
  4. Supported by various CI servers and some that don’t support native plugins.
  5. The explanatory syntax for the BDD paradigm.
  6. AngularJS usage is extensively supported.
  7. Jasmine does not rely on any other JavaScript framework.
  8. Jasmine does not need any DOM.
  9. All the syntax used in the Jasmine framework is neat and apparent.
  10. Jasmine is heavily impacted by JS Spec, Rspec, and Jspec.
  11. Jasmine is an open-source framework and effortlessly available in various versions like stand-alone, Node.js, ruby gem, etc.

Cons:

  1. Asynchronous testing is rather tough.
  2. Expects a particular suffix to all test files.

How to Use Jasmine?

Jasmine is very susceptible to execute in any type of development method. All you require to download is the standalone library files from the official website i.e. https://jasmine.github.io/ and enforce the same in your application. The comprehensive environment setup will be defined later. Once you successfully install and unzip the zip file, then you will discover the sub-folders inside that zip file. Now let’s move ahead and explore just as we will discuss jest vs jasmine too.

Jest vs jasmine

Jest

Jest is a JavaScript test runner, i.e., a JavaScript archive or library for building, running, and structuring tests. Jest boats as an NPM package, you can download it in any JavaScript project. It is one of the most outstanding test runners nowadays, and the default option for React projects.

The first thing you should know: how do you know what to test?

When it comes to testing, just an easy block of code could immobilize learners. The most familiar question is this- “How do I understand or know what to test?”

If you’re jotting down a web application an adequate beginning point would be testing every page of the app and every user interaction. However, web applications are also created of units of code such as for purposes and modules that require to be tested too.

There are two strategies maximum of the times:

  • you inherit legacy code which arrives without tests
  • you have to execute a fresh functionality out of thin air

Now, what to do? Well, for both cases you can enable yourself by an understanding of tests as fractions of code that test if a provided function generates the expected outcome.

Here’s how a particular test flow seems like:

  1. import the function to test
  2. provide input to the function
  3. describe what to expect as the outcome
  4. check if the function generates the expected output

That’s it as testing won’t be difficult anymore if you understand in these terms: input – expected result – assert the result.

Specifications and test-driven development

As creators, we all like freedom and creativity. However, when it comes to serious matters most of the time you don’t possess so much freedom. We’ve bought to follow specifications, that is, a written or verbal explanation of what to create. A super crucial customer needs a JavaScript function that should filter a collection of objects.

For every object, we should test a property called “URL” and if the significance of the property matches a given term then we should encompass the matching object in the occurring array. Being a test-savvy JavaScript developer you need to follow test-driven development, a discipline that assesses to write a failing test before beginning to code. We will also explore jest vs jasmine but before that let’s see how to test react with jest.

jest vs jasmine

How to test React with Jest?

React is a greatly famous JavaScript library for building dynamic user interfaces. Jest functions smoothly for testing React apps, Jest, and React both are from Facebook’s engineers. Jest is further the default test runner in create-react-app. At the time of writing if you want to utilize import ES module syntax in your Jest tests without babel and friends then you should possess Node.js >=v13.x, and Jest >=26.1.0 installed.

If you don’t wish to blunder your default Node.js version you can utilize a tool such as nvm to install many Node.js versions. Once nvm is in the position you can install the recent release of Node.js. 

nvm install node

To create import work in Jest, package.json should possess the key type configured as a module, and Jest must be named through Node.js with a flag:

  “scripts”: {

    “test”: “node –experimental-vm-modules node_modules/jest/bin/jest.js”

  },

  “type”: “module”,

Once accomplished you can begin using import in Jest. Presume you like to test a module at src/SimpleModule.js:

export function simpleFunc() {

  return “Hello!”;

}

export function complexFunc() {

  return “complex!”;

}

In a test file at __tests__/SimpleModule.spec.js you can import the module as you would do normally:

import { simpleFunc } from “../src/SimpleModule”;

describe(“A simple module”, () => {

  test(“it should say hello”, () => {

    expect(simpleFunc()).toEqual(“hello!”);

  });

});

You should note that things could differ a bit in the future, keep an eye on this problem. Now let’s have a glimpse at mocha.

Mocha

Mocha is considerably more flexible, but you have to part it together yourself. There is no spy framework created into Mocha, so maximum people use sinon.js. There’s no assertion framework manufactured into Mocha, so you’ll have to choose one. You can further configure Mocha for BDD (jasmine style) or TDD effortlessly. You have to select and choose how you like Mocha to function.

jest vs jasmine

Perhaps for this flexibility (tremendous to build the test environment that you certainly need) or because it’s simple to switch from Jasmine to Mocha, JavaScript users are beginning to prefer it above other test frameworks. Let’s look at its advantages below.

Advantages:

  1. Easy setup.
  2. Headless running out of the box.
  3. Enables use of any assertion library that will throw exceptions on failure.
  4. Tons of plugins, highly extensible.
  5. It functions rather nice with asynchronous testing.
  6. Has aliases for processes to be more BDD or TDD-oriented.
  7. Asynchronous testing is a breeze.

Disadvantages:

  1. It remains to be the newer on the field, so sometimes there could be an absence of support in distinct areas.

To conclude, it is crucial to point out that, although Jasmine does not possess a test runner and Mocha on the other hand comprises one and an API for setting up the test suite. Both libraries are supported by the prominent test runner Karma. Karma can operate your tests against various browsers. So, if you were to select a test framework set up now, you will probably use Karma for the test runner. This provides you consecutive feedback while formulating your code.

Hopefully, this blog has made it more obvious as to what some of the fundamental differences are between Jasmine and Jest and Mocha. If you have any queries, please do not think twice to contact us. We will be glad to help you. Testing is a huge and interesting topic. There are various types of tests and many libraries for testing. In this jest vs jasmine tutorial, you understood how to configure Jest for coverage reporting, how to govern and write a simple unit test, and how to test JavaScript code, and nonetheless, you have learned everything jasmine js, javascript jasmine, and javascript match.