README.md

Introduction to Unit Testing in JavaScript

Installation

First, clone this repository. For this lesson we will be using a repository set up to run Node.js, which means you'll be seeing some commands we haven't discussed that start with npm. We aren't going to dig into what this means today, but ultimately it allows us to pull in some powerful tools outside of our basic html/css/js files.

git clone git@github.com:turingschool-examples/testing-javascript.git  

Once, you have it on your computer, cd into the directory in the terminal and run the following command:

npm install

This command installs all of the dependencies we need to run tests.

Getting Started

We'll be modifying two files as we complete these exercises:

• implentation.js
• test.js

Just to verify that everything works, there should be a first example in place.

// implementation.js
function square(num) {
  return num * num;
}

// test.js
describe('square', function () {

  it('returns the square of a number', function () {
    var result = square(2);

    assert.equal(result, 4);
  });

});

Running a Test

From your command line, make sure you are navigated into this repository's root. Run the following:

npm test test.js

What is that doing? npm test is the command, and test.js is the single argument we are passing it. We are telling the computer to run tests, specifically, the tests is test.js file.

Together

Let's write a few cases together.

• addTwo();
• multiplyTwo();
• largerNumber();

Your Turn

Pro Tip: Feel free to google to figure out how to implement some of this logic.

Subtract

Create a function that subtracts the second argument from the first argument passed in. For instance:

subtract(5, 3);

=> 2

subtract(12, 2);

=> 10

Longer Word

Create a function that finds which argument contains the longer word. For instance:

longerWord("hi", "hello");

=> "hello"

longerWord("hey", "hi");

=> "hey"

Reverse String

Create a function that reverses a string that is passed in as a parameter. For instance:

reverseString('reverse');

=> 'esrever'

Try to do this without using the .reverse() function in JavaScript.

Longest Word

Create a function that can find the longest word in a sentence. For instance:

findLongestWord('We had a great time!');

=> 'great'

Time Convert

Create a function that converts a number of minutes passed in as a parameter to the hours and minutes separated by a colon. For instance:

convertTime(126);
'2:06'

convertTime(45);
=> '0:45'

FizzBuzz

FizzBuzz is a classic programming program that a lot of programmers apparently can't do.

We're going to write a function called fizzBuzz() that will behave as follows with the each rule taking precedence over all previous rules:

• If we pass it a number, it will return that number.
• If we pass a number that is a multiple of 3, it will return 'Fizz'.
• If we pass it a number that is a multiple of 5, it will return 'Buzz'.
• If we pass it a number that is a multiple of both 3 and 5, it will return 'FizzBuzz'.

Resources

• Mocha Docs
• Chai Docs

Dive Deeper

• Running Tests In the Browser
• Blog Post about TDD vs BDD