test driven development with phpunit

Test Driven Development with PHPUNITTuan Nguyen, Full Stack Developer

Welcome

Background and Motivation - My Background

Tuan Nguyen

• 7+ years of experience in web development

• Recent position: Software development team lead

• Recent project: Enterprise Content Management System

Background and Motivation - Unit Testing

Most of the developers (I know) don’t like Unit Testing. Why?

• “Not having enough time”

• “I understood the requirements and I have implemented them carefully in the code”

• “This part is not so important”

• “I am lazy”


Benefits of unit testing

• Unit Tests reduce bugs

• Unit Tests are good documentation

• Unit Tests improve design

• Unit Tests prove your code actually works

• Unit Test are vital to regression testing


Unit test is a requirement for Software Engineer

Workflow of TDD and Unit Test

3 Laws of TDD

• Create a test that fails

• Write code to pass the test

• Clean up the code

Demonstration of TDD and Unit Test

The problem to solve

Build a simple calculator with four functions: adding, subtracting, multiplying and dividing. [5]


The tools we need

• MAMP - Virtual web servers on local machine

• PHP Composer - Manage open source PHP libraries

• PHPUnit - PHP test frameworks

• Sublime Text - Development-friendly text editor


Create a project


Install PHPUnit


Installed PHPUnit in vendor folder


CalculatorTest.php file with first test case

Demonstration of TDD and Unit TestFirst test doesn’t pass

Demonstration of TDD and Unit TestCreate class Calculator.php to pass the test

Demonstration of TDD and Unit Testsetup() and tearDown() function in PHPUnit

Demonstration of TDD and Unit TestThe first real test - testAdd()

Demonstration of TDD and Unit TestWrite code to pass the test - add() function with bug

Demonstration of TDD and Unit TestTest result of add() function with bug

Demonstration of TDD and Unit TestFix the bug to pass the test

Demonstration of TDD and Unit TestPass the test for add() function

Demonstration of TDD and Unit TestApply these steps for other functions: subtract(), multiply(), divide()

• Full source of CalculatorTest.php - http://pastebin.com/pAFAZJDC

• Full source of Calculator.php - http://pastebin.com/zXhiVLR8

References[1] Top 12 Reasons to Write Unit Tests, http://www.onjava.com/pub/a/onjava/2003/04/02/javaxpckbk.html

[2] Unit testing: Why bother?, http://soundsoftware.ac.uk/unit-testing-why-bother/

[3] The Cycles of TDD, http://blog.cleancoder.com/uncle-bob/2014/12/17/TheCyclesOfTDD.html

[4] Test Driven Development (TDD) using PHPUnit, http://diogoosorio.com/blog/test-driven-development-tdd-using-phpunit

[5] Test Driven Development With PHP, https://paulund.co.uk/test-driven-development-with-php

[6] Let's TDD a Simple App in PHP, http://code.tutsplus.com/tutorials/lets-tdd-a-simple-app-in-php--net-26186

Thank You!Tuan Nguyen, [email protected]