Unit Testing für Dummies

15.11.2009

Lars Jankowfsky, swoodoo AGThorsten Rinne, Mayflower GmbH

About me:

PHP, C++, Developer, Software Architect since 1992

PHP since 1998

Many successful projects from 2 to 20 developers

Running right now three projects using eXtreme Programming

CTO and (Co-)Founder swoodoo AG

(Co-)Founder OXID eSales AG

About me:

Diplom-Informatiker (FH) Certified Scrum MasterZend Certified Engineer

PHP since 1999

Many successful projects from 2 to 6 developers using Scrum, eXtreme Programming, Crystal Clear

Senior Developer / Team Lead at Mayflower GmbH

Master of phpMyFAQ

(c) aboutpixel.de(c) spackletoe http://www.flickr.com/photos/spackletoe/90811910/)

Unit Tests?

PHPUnit Fixtures

Stubs Pitfalls

PHPUnithttp://www.phpunit.de/

PHPUnit

phpunit myTest

user@workshop:/var/www/thorsten-zfguestbook/tests/application$ phpunit controllers_PostsControllerTest

PHPUnit

Fixtures

Fixtures Fixtures

Make sure that tests don‘t alter fixture

Fixture is FIXture

if you feel creating fixtures is too much work - refactor more!

Do never let tests leave altered tests

Fixtures the Ruby way...

Ruby uses YAML

www.yaml.org

PHP YAML support done by using Syck

Syck = YAML + fast

http://whytheluckystiff.net/syck/

http://www.frontalaufprall.com/2008/05/05/php-unit-database-fixtures-the-ruby-way/

Fixtures

YAML loading

public static function create($fileName) { $fileName = 'Fixtures'.DIRECTORY_SEPARATOR.$fileName; ob_start(); include $fileName; $fileContents = ob_get_contents(); ob_clean(); $yamlData = syck_load($fileContents); return $yamlData; }

Fixtures

YAML storing

public static function load($fixtures, $tableName) { if (is_array($fixtures) && count($fixtures)) { foreach ($fixtures as $fixture) { if (is_array($fixture) && is_array(current($fixture))) { Fixtures::load($fixture, $tableName); } $fields = array_keys($fixture); $statement = "INSERT INTO $tableName (" . implode(', ', $fields) . ") VALUES (:" . implode(", :", $fields) . ")"; $stmt = self::$_db->prepare($statement); if (count($fixture)) { foreach ($fixture as $key => $value ) { $stmt->bindValue(':'.$key, $value); } } $stmt->execute(); self::$_usedTables[$tableName] = $tableName; } } }

Fixtures

YAML - cleanup

if (!empty(self::$_usedTables)) { foreach (array_reverse(self::$_usedTables) as $tableName) { self::$_db->execute("TRUNCATE TABLE $tableName"); } }

Fixtures

Fixtures the other side ...

manual fixtures are too much work

use a test database

think about automatic creation of YAML files

Fixtures

Stubs

Mocking stubs? Stubs

Unittesting is about testing a unit of work, not a complete workflow

isolates your code from external dependencies

can be done with PHPUnit, but you don‘t need to

Mocking stubs The PHPUnit way Stubs

/** * A simple stub providing a simple result directly instead of using the database */class UserModelStub extends UserModel { public getUserCount() { return 10; }}

UserModelStub extends PHPUnit_Framework_Testcase { public function testGetUserCount() { $stub = $this->getMock(‘UserModel‘); $stub->expects($this->any())->method(‘getUserCount‘)->will($this->returnValue(10)); }}

Pitfalls

Code the unit test first. Pitfalls

OOP, public, private

Globals

Superglobals

Sessions

Cookies

Dependencies ...

Separate logic from view

create accessors, add all parameters in calls

Pitfalls

Dependency Example

class displayUserDetails(){ /** * Processes input and sends user first name, last name to display; */ function show() { global $dbLink; global $templateEngine; $itemId = (int) $_REQUEST['user_id']; $firstName = $dbLink->getOne("select first_name from users where id = $itemId"); $lastName = $dbLink->getOne("select last_name from users where id = $itemId"); $templateEngine->addTemplateVar('firstName', $firstName); $templateEngine->addTemplateVar('lastName', $lastName); $templateEngine->display(); }}

Pitfalls

Dependency Example

/** * A view class responsible for displaying user details. */class userView(){ /** * Loads user object and sends first name, last name to display */ public function show() { $userId = $this->_inputProcessor->getParameter("user_id"); $this->templateEngine->addTemplateVar('user', $this->model->loadUser(userId)); $this->templateEngine->display(); }} /** * And the corresponding model */class userModel(){ public function loadUser($userId) { $user = new User( $userId ); return array('firstName' => $user->getFirstName(), 'lastName' => $user->getLastName()); }}

Pitfalls

STOP

class someOtherClass { var $setting;

function calculateSomething($a, $b) { return $a+$b; }}

class myOldNastyClass {

function needToTestThisFunction() {

$class = new someOtherClass();

$z = $_GET['input'];

// ....

return $class->calculateSomething( $class->setting, $z); }}

Layer Example Pitfalls

Layer Example

class someOtherClass { private $setting;

public function calculateSomething($a, $b) { return $a+$b; }

public function setSetting($set) { $this->setting = $set; }

public function getSetting() { return $this->setting; }}

class myInput { public function getParameter($name) { return $_GET[$name]; }}

class myOldNastyClass {

private $input; // set e.g. in constructor

public function needToTestThisFunction(someOtherClass &$class, $z) {

$z = $input->getParameter('input'); // ....

return $class->calculateSomething( $class->getSetting(), $z); }}

Pitfalls

(c) istockphoto

„Questions?“