While working on any JavaScript project, it is important to write tests for your project features/components as much as it is important to create the project features themselves.

Unit testing in Node.js is a process where by the developer in charge of a project creates a module that helps to test whether a feature that was added in the project was working as it should be.

Most of the time, unit tests are usually performed on individual functions of a feature or project and each function/feature is referred to as a unit.

Node.js provides an easy way for developers to create unit tests for their project features through a very effective package known as Mocha.

Mocha.js is a wonderful JavaScript test framework with wonderful features that helps to simplify the process of unit testing.


#### Using Mocha

In order to use Mocha to create unit tests in your projects, you need to install the package.

To install Mocha, run this command in your project terminal

```
npm install mocha
```

Moving forward, we are going to create a new directory in the root directory of our project and name it `test`.

In the `test` directory, create a file `new.test.js`.

Now, we are going to test a function in the file to show how Mocha works.

We are going to use a npm package to run a test that checks whether the square root of any passed value is returning the correct data.

Let;s install the package by running the command

```
npm install mathjs
```
in `new.test.js` add the following code

```
const { sqrt } = require('mathjs')
const  assert = require('assert');

describe('Square root Test', () => {
	it('should return 2', () => {
		assert.equal(sqrt(4).toString(), 2);
	});
	it('should return 3', () => {	
		assert.equal(sqrt(9).toString(), 3);
	});
});
```

In `package.json`, add this in your `scripts` object

```
"test": "mocha"
```

In your terminal, run the command `npm run test` in order to run the test we created

If the function we tested in returning the correct data, we should see the following result in the terminal log

![enter image description here](https://i.ibb.co/7nK3CZz/new.png)

If the function had failed, which it would have had we passed the wrong data such as in the example below

```
const { sqrt } = require('mathjs')
const  assert = require('assert');

describe('Square root Test', () => {
	it('should return 3', () => {
		assert.equal(sqrt(4).toString(), 3);
	});
	it('should return 12', () => {	
		assert.equal(sqrt(9).toString(), 12);
	});
});
```

Had we run the code above we would get a result similar to this

![enter image description here](https://i.ibb.co/St1NkPT/new.png)

There are numerous ways in which one can use Mocha to conduct  unit tests on ones project but I am unable to cover the full scope in this post.

If you are interested in implementing Mocha in your projects you can refer to the following resources to understand the nitty-gritties of the package

- [https://medium.com/serverlessguru/how-to-unit-test-with-nodejs-76967019ba56](https://medium.com/serverlessguru/how-to-unit-test-with-nodejs-76967019ba56)
- [https://mochajs.org/](https://mochajs.org/)
- [https://github.com/mochajs/mocha](https://github.com/mochajs/mocha)
- [https://www.npmjs.com/package/mocha](https://www.npmjs.com/package/mocha)

I really hope you found this post useful, drop your comments and opinions below, thanks for reading.