Test Driven Development

Abel Sanchez and John R. Williams

Software Life Cycle

Github

TDD

TDD Workflow

• Write a test
• Watch it fail
• Write the code
• Watch it fail
• Fix
• Watch it pass
• Feel good
• Add, commit, push, pull request

Mocha Test Framework

http://mochajs.org/

Install Mocha Globally

					$ npm install mocha -g
					

Create NPM App

Let's start by creating a new directory

					$ mkdir newdir
					

					$ cd newdir
					

Initialize Application

Initialize application, set "test" property to "mocha || true"

					$ npm init
					

					Press ^C at any time to quit.
					name: (testor) 
					version: (1.0.0) 
					description: use mocha tests
					entry point: (index.js) 
					test command: mocha || true
					

Sample Metadata

Sample package.json file

					{
					  "name": "testor",
					  "version": "1.0.0",
					  "description": "tdd",
					  "main": "index.js",
					  "directories": {
					    "test": "test"
					  },
					  "scripts": {
					    "test": "mocha || true"
					  },
					  "author": "abel@mit.edu",
					  "license": "MIT"
					}
					

Add A Code File

Write a code file, call it sum.js

					function sum(a, b) {
					  return a + b;
					}
					module.exports = sum;
					

Write a Test File

Write a test file, call it test/test.js

					var sum = require('../sum.js');
					var assert = require('assert');

					describe('check functions', function() {

					  describe('add', function() {
					    it('it should return 2 when we pass 1,1', function() {
					      assert.equal(2, sum(1,1));
					    });
					  });

					});
					

Run Test

					$ npm test
					

Sample output

Jest Test Framework

https://github.com/facebook/jest

Install Jest Globally

					$ npm install -g jest
					

Create NPM App

Let's start by creating a new directory

					$ mkdir newdir
					

					$ cd newdir
					

Initialize Application

Initialize application, set "test" property to "jest"

					$ npm init
					

					Press ^C at any time to quit.
					name: (testor) 
					version: (1.0.0) 
					description: use jest tests
					entry point: (index.js) 
					test command: jest
					

Sample Metadata

Sample package.json file

					{
					  "name": "testor",
					  "version": "1.0.0",
					  "description": "jest tests",
					  "main": "index.js",
					  "scripts": {
					    "test": "jest"
					  },
					  "author": "abel@mit.edu",
					  "license": "MIT"
					}
					

Add A Code File

Write a code file, call it sum.js

					function sum(a, b) {
					  return a + b;
					}
					module.exports = sum;
					

Write a Test File

Write a test file, call it sum.test.js

					const sum = require('./sum');

					test('adds 1 + 2 to equal 3', () => {
					  expect(sum(1, 2)).toBe(3);
					});
					

Run Test

					$ npm test
					

Sample output