Testing with Mocha

Mocha is a popular open source JavaScript test framework for both Node.js and the browser. Mocha comes with many features.

In this recipe, we're going to write test cases using Mocha for a simple calculator program.

Getting ready

1. Let's first create a directory to work in and initialize our project directory:

   $ mkdir testing-with-mocha
   $ cd testing-with-mocha
   $ npm init --yes

2. We need to have a program that we can test. We'll create a small calculator program that we can use to learn how to unit test with Mocha. Create a file named calculator.js:

   $ touch calculator.js

3. Now, we can add the following to calculator.js for our calculator program:

   module.exports.add = (number1, number2) => {
       return number1 + number2;
   };
   module.exports.subtract = (number1, number2) => {
       return number1 - number2;
   };
   module.exports.multiply = (number1, number2) => {
       return number1...