This document discusses an introduction to test-driven development (TDD) using PHPUnit and provides an example FizzBuzz kata. It begins by addressing common misconceptions about TDD and how TDD can actually reduce time spent debugging and increase confidence in changes. The document then explains how TDD works by making assertions about promises or expectations. It provides details on how to set up a basic TDD kata using PHPUnit, including creating test and code files. The rest of the document demonstrates a FizzBuzz kata as an example TDD exercise.

1. Intro to TDD Using
PHPUnit: A FizzBuzz
Kata
2015 January 7
Kansas City PHP User Group

2. TDD is Stupid
• Writing tests takes time
• I’d rather be coding
• No way I can test everything

3. TDD is Stupid Smart
• Reduces time spent in debugger
• Reduces var_dump and bogus echo statements
• Reduces fear of change

4. Easiest TDD Deals With
Promises
• All tests start with a descriptive name, the promise:
• ex. testEvenNumbersAreDivisibleBy2
• All tests end with $this->assertSomething
• The assert is the final statement of the proof.
• ex.
When Even Numbers Are Divisible By 2,
Assert that (EvenNumber % 2) == 0
Assert that (OddNumber % 2) == 1.

5. TDD Kata
• Kata are are short series of movements repeated enough to be
done without thought — migrating intention into muscle-memory.
• Learn TDD concepts via kata
• True TDD kata are done, discarded, and repeated.
• Non-TDD-Kata Examples:
• Karate Kid III - Kata Scene
• Rika Usami of Japan. 宇佐美 里香。空手 - Final Female Kata

6. Essentials
• To start a TDD Kata using PHPUnit, you need:
• composer.json
• a KataClassTest.php
• a KataClass.php
• You do NOT need to implement the KataClass!

7. Fizz Buzz Kata
• Rules:
• Given a series of numbers, replace certain numbers with
a string.
• Numbers divisible by 3 are replaced by “Fizz”
• Numbers divisible by 5 are replaced by “Buzz”
• Numbers divisible by (3 and 5) are replaced by
“FizzBuzz”
• All other numbers are unchanged

8. Enough Talk. Begin!
• Add the following to composer.json:
• "require-dev": {
"phpunit/phpunit": “~4.4"
}
• Set up environment via Composer:
• $ composer install

9. Test Class
• Create FizzBuzzTest.php
• <?php
include 'vendor/autoload.php';
class FizzBuzzTest extends
PHPUnit_Framework_TestCase
{
}

10. Test, then Fix
• run $ vendor/phpunit/phpunit/phpunit —colors
FizzBuzzTest.php
• Errors!
• Fix ‘em.
• Test again.

11. Demonstration

12. Now, go and study
• PHPUnit:
• Documentation: https://phpunit.de/documentation.html
• Presentations: https://phpunit.de/presentations.html
• Grumpy Programmer Books:
• The Grumpy Programmer's PHPUnit Cookbook: https://leanpub.com/grumpy-phpunit
• The Grumpy Programmer's Guide To Building Testable PHP Applications:
https://leanpub.com/grumpy-testing
• Kata:
• 12 TDDs of Christmas: http://www.wiredtothemoon.com/2012/12/12-tdds-of-christmas/
• http://cyber-dojo.org/
• http://www.codewars.com/

13. Thank you
Eric Poe
eric@ericpoe.com
@eric_poe
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