Automated Testing with PHPUnit

How do you know your code works?

Manual Testing• Type in a value• Submit the form• Check by eye

Manual Testing• Tedious• Time Consuming• Error Prone• Did you test everything?• Consistently?

Automated TestingHave the computer run your tests

Pro: ConfidenceKnow that your code does what it needs toKnow that your code doesn’t break anything that used to work

Regression Testing

Con: Testing isn’t free• Writing tests takes time• Response: So does manual testing

• Mo Code Mo Problems• Response: It’s a worthwhile investment

Unit TestingAutomated testing one unit at a time

What is a unit?Module (procedural programming)Class (OOP)

Breaking Down Unit Tests• Test Suite composed of• Test Case Classes each of which

have• Test Methods which make 1 or more• Assertions

A Unit Test Asserts That A Unit Of Code Performs To A Specification

HelpXUnit Frameworks

XUnit Frameworks Provide• Assertions• Calls Test Methods• Help Setup• Test Cases• Test Runners

Assertions• Code to verify that

expected and actual values match

• Often methods starting with “assert…()” or “refute…()”

• Used by the developer

$this->assertTrue()

$this-> assertFalse()

$this-> assertEquals()

Calls Test Methods• Knows to call your

code which tests a particular condition, method, or other “sub unit”

• Methods usually begin with “Test…()”

• Written by the developer

class … {public function test…() { … }

}

Help setUp and tearDownOffers special functions that get called before and after each test.Written by the developer

class … {public

function setUp() {…}public function tearDown() {…}

}

Unit Test Life Cycle

TestCase:: setUp()

TestCase:: test*()

TestCase:: tearDown()

Test Case• A class with test

methods• Usually offers

assert methods• Extended by the

developer

class MyTest extends PHPUnit_Framework_ TestCase {…}

Provide Test RunnersCode that makes executing tests simpleOften a command-line tool

(useable by IDE)

Test First or Test Last?

Test FirstTest Driven Development (TDD)

Testing Cycle

Write Test

Confirm Test Fails

Make Test Pass

Ensure All Tests

Pass

Find Problems EarlyHow should your code work?What do the requirements mean?

Manage Scope CreepDo The Simplest Thing That Could Possibly WorkYAGNIKnow when you’re done: All tests are green.

Test LastProblematicTests become biased for the code you already wrote

What don’t you test?

Don’t Test the Language/Framework

Don’t test session session initiaitonOr $_POST/$_GET/etc.Or anything provided by PHP (and/or your framework,

$_POST[“loggedIn”] = true;$this-> assertTrue($_POST [“loggedIn”])# Wrong!

Don’t Test Methods Without Logic

class … { private $foo; public get_foo() { return $this->foo; }}

What to Test

Boundariesfunction … {

if ($foo > 3) { // test whether execution goes in here}else { // test whether execution goes in here}

}

Invalid values• 0• Negative values• Empty strings• Very long strings (>500chars)

What’s a good test?• Repeatable• Use setUp() to make sure everything is

right for your test• Independent• Use tearDown() to clean up

• Thorough• It’s ok to have more than one test

method in your case… in fact it’s often necessary!