Getting Started With PHPUnit

Getting Started with PHPUnit Sebastian Bergmann March 11th 2010

Sebastian Bergmann  Co-Founder and Principal Consultant with thePHP.cc  Pioneer in the field of QA for PHP projects  Creator of PHPUnit  Contributor to PHP

Throwaway code (sometimes) has a right to exist. But this is not what we are dicussing here today.

We are interested in code that is to be maintained over a long period of time.

It is okay to never test code that never changes. For everything else, you need tests. (Timothy Fitz)

Unit Testing Testing a unit of code isolated from its dependencies.

Unit Tests are like a warm blanket you can wrap yourself into if you need to go out into the code forest to refactor. (Volker Dusch)

Examples to introduce unit tests are boring. Please bear with me and do not fall asleep!

The BankAccount example BankAccount.php <?php class BankAccount { protected $balance = 0; public function getBalance() { return $this->balance; } protected function setBalance($balance) { if ($balance >= 0) { $this->balance = $balance; } else { throw new BankAccountException; } } public function depositMoney($balance) { $this->setBalance($this->getBalance() + $balance); return $this->getBalance(); } public function withdrawMoney($balance) { $this->setBalance($this->getBalance() - $balance); return $this->getBalance(); } }

The BankAccount example BankAccountTest.php <?php require_once 'BankAccount.php'; class BankAccountTest extends PHPUnit_Framework_TestCase { }

The BankAccount example BankAccountTest.php <?php require_once 'BankAccount.php'; class BankAccountTest extends PHPUnit_Framework_TestCase { public function testBalanceIsInitiallyZero() { } }

The BankAccount example BankAccountTest.php <?php require_once 'BankAccount.php'; class BankAccountTest extends PHPUnit_Framework_TestCase { public function testBalanceIsInitiallyZero() { $ba = new BankAccount; $this->assertEquals(0, $ba->getBalance()); } }

The BankAccount example Running the test(s) sb@ubuntu ~ % phpunit BankAccountTest PHPUnit 3.4.12 by Sebastian Bergmann. . Time: 0 seconds, Memory: 3.25Mb OK (1 test, 1 assertion)

The BankAccount example Tests can serve as an executable specification.

The BankAccount example Tests can serve as an executable specification. sb@ubuntu ~ % phpunit --testdox BankAccountTest PHPUnit 3.4.12 by Sebastian Bergmann. BankAccount [x] Balance is initially zero

The BankAccount example Leverage the setUp() template method <?php require_once 'BankAccount.php'; class BankAccountTest extends PHPUnit_Framework_TestCase { protected $ba; protected function setUp() { $this->ba = new BankAccount; } public function testBalanceIsInitiallyZero() { $this->assertEquals(0, $this->ba->getBalance()); } }

The BankAccount example More tests … <?php require_once 'BankAccount.php'; class BankAccountTest extends PHPUnit_Framework_TestCase { // ... public function testBalanceCannotBecomeNegative() { try { $this->ba->withdrawMoney(1); } catch (BankAccountException $e) { $this->assertEquals(0, $this->ba->getBalance()); return; } $this->fail(); } }

The BankAccount example More tests … <?php require_once 'BankAccount.php'; class BankAccountTest extends PHPUnit_Framework_TestCase { // ... public function testBalanceCannotBecomeNegative2() { try { $this->ba->depositMoney(-1); } catch (BankAccountException $e) { $this->assertEquals(0, $this->ba->getBalance()); return; } $this->fail(); } }

The BankAccount example More tests … <?php require_once 'BankAccount.php'; class BankAccountTest extends PHPUnit_Framework_TestCase { // ... public function testDepositingAndWithdrawingMoneyWorks() { $this->assertEquals(0, $this->ba->getBalance()); $this->ba->depositMoney(1); $this->assertEquals(1, $this->ba->getBalance()); $this->ba->withdrawMoney(1); $this->assertEquals(0, $this->ba->getBalance()); } }

The BankAccount example More tests … sb@ubuntu ~ % phpunit --testdox BankAccountTest PHPUnit 3.4.12 by Sebastian Bergmann. BankAccount [x] Balance is initially zero [x] Balance cannot become negative [x] Depositing and withdrawing money works

The BankAccount example is finished. You can all wake up again :)

Categories of (Unit) Tests  Small: Unit Tests  Check conditional logic in the code  A debugger should not be required in case of failure  Medium: Functional Tests  Check whether the interfaces between classes abide by their contracts  Large: End-to-End Tests  Check for ”wiring bugs”

Software Testing Pyramid End-to-End Tests Functional Tests Unit Tests

Functional tests can tell you something broke.

Functional tests can tell you something broke. Unit tests can tell you what broke. (Jason Huggins)

Testable Code ”The secret in testing is in writing testable code” Miško Hevery

This presentation is not about architecture. But for thinking about testability it makes sense to look at MVC.

So far we only tested the model.

What about the controller?

ModelViewController A minimalistic MVC implementation  Request  Encapsulate all input  Response  Encapsulate all output  FrontController  Request → Controller → Response  Model ↔ Controller → View

ModelViewController The Request class <?php class Request { protected $data; public function __construct(array $server = array(), array $get = array(), array $post = array(), array $cookie = array(), array $files = array(), array $env = array()) { $this->data['server'] = $server; $this->data['get'] = $get; $this->data['post'] = $post; $this->data['cookie'] = $cookie; $this->data['files'] = $files; $this->data['env'] = $env; } public function __call($type, array $arguments) { if (!isset($this->data[$type])) { throw new BadMethodCallException; } if (empty($arguments) || !isset($this->data[$type][$arguments[0]])) { throw new InvalidArgumentException; } return $this->data[$type][$arguments[0]]; } }

ModelViewController The Response class <?php class Response { protected $headers = array(); protected $data = array(); public function addHeader($header) { $this->headers[] = $header; } public function setData($key, $value) { $this->data[$key] = $value; } }

ModelViewController The FrontController class <?php class FrontController { protected $request; protected $response; public function __construct() { $this->request = new Request( $_SERVER, $_GET, $_POST, $_COOKIE, $_FILES, $_ENV ); $this->response = new Response; } } Request and Response cannot be injected

ModelViewController The FrontController class <?php class FrontController { protected $request; protected $response; public function __construct(Request $request, Response $response) { $this->request = $request; $this->response = $response; } }

ModelViewController The FrontController class <?php class FrontController { // ... public function dispatch(Router $router) { $controller = $router->route($this->request); $view = $controller->execute( $this->request, $this->response ); return $view; } }

ModelViewController index.php <?php function __autoload($class) { require $class . '.php'; }

ModelViewController index.php <?php function __autoload($class) { require $class . '.php'; } $request = new Request( $_SERVER, $_GET, $_POST, $_COOKIE, $_FILES, $_ENV );

ModelViewController index.php <?php function __autoload($class) { require $class . '.php'; } $request = new Request( $_SERVER, $_GET, $_POST, $_COOKIE, $_FILES, $_ENV ); $response = new Response;

ModelViewController index.php <?php function __autoload($class) { require $class . '.php'; } $request = new Request( $_SERVER, $_GET, $_POST, $_COOKIE, $_FILES, $_ENV ); $response = new Response; $frontController = new FrontController( $request, $response );

ModelViewController index.php <?php function __autoload($class) { require $class . '.php'; } $request = new Request( $_SERVER, $_GET, $_POST, $_COOKIE, $_FILES, $_ENV ); $response = new Response; $frontController = new FrontController( $request, $response ); $router = new Router; $router->addRoute('/', 'DefaultController');

ModelViewController index.php <?php function __autoload($class) { require $class . '.php'; } $request = new Request( $_SERVER, $_GET, $_POST, $_COOKIE, $_FILES, $_ENV ); $response = new Response; $frontController = new FrontController( $request, $response ); $router = new Router; $router->addRoute('/', 'DefaultController'); $view = $frontController->dispatch($router); $view->render();

EndtoEnd Testing <?php function __autoload($class) { require $class . '.php'; } class EndToEndTest extends PHPUnit_Framework_TestCase { public function testSomething() { } }

EndtoEnd Testing Create a Request object with test input <?php function __autoload($class) { require $class . '.php'; } class EndToEndTest extends PHPUnit_Framework_TestCase { public function testSomething() { $request = new Request(array('REQUEST_URI' => '/')); } }

EndtoEnd Testing Create a Response object <?php function __autoload($class) { require $class . '.php'; } class EndToEndTest extends PHPUnit_Framework_TestCase { public function testSomething() { $request = new Request(array('REQUEST_URI' => '/')); $response = new Response; } }

EndtoEnd Testing Create a FrontController object <?php function __autoload($class) { require $class . '.php'; } class EndToEndTest extends PHPUnit_Framework_TestCase { public function testSomething() { $request = new Request(array('REQUEST_URI' => '/')); $response = new Response; $frontController = new FrontController( $request, $response ); } }

EndtoEnd Testing <?php function __autoload($class) { require $class . '.php'; } class EndToEndTest extends PHPUnit_Framework_TestCase { public function testSomething() { $request = new Request(array('REQUEST_URI' => '/')); $response = new Response; $frontController = new FrontController( $request, $response ); // Do something } }

EndtoEnd Testing <?php function __autoload($class) { require $class . '.php'; } class EndToEndTest extends PHPUnit_Framework_TestCase { public function testSomething() { $request = new Request(array('REQUEST_URI' => '/')); $response = new Response; $frontController = new FrontController( $request, $response ); // Do something // Perform assertion(s) on the $response object } }

EndtoEnd Testing Imagine that we did not have Request and Response <?php function __autoload($class) { require $class . '.php'; } class EndToEndTest extends PHPUnit_Framework_TestCase { public function testSomething() { $_SERVER['REQUEST_URI'] = '/'; // Do something // Perform assertion(s) on ... what exactly? } }

And what about the view? The view should be so ”dumb” that it requires no testing.

PHPUnit Best Practices

PHPUnit Best Practices Use an XML Configuration File <?xml version="1.0" encoding="UTF-8"?> <phpunit> <testsuites> <testsuite name="My Test Suite"> <directory>path/to/dir</directory> </testsuite> </testsuites> </phpunit>

PHPUnit Best Practices Use a bootstrap script <?xml version="1.0" encoding="UTF-8"?> <phpunit bootstrap="/path/to/bootstrap.php"> <testsuites> <testsuite name="My Test Suite"> <directory>path/to/dir</directory> </testsuite> </testsuites> </phpunit>

PHPUnit Best Practices bootstrap.php <?php function __autoload($class) { require $class . '.php'; }

PHPUnit Best Practices Configure the test suite using the XML configuration file <?xml version="1.0" encoding="UTF-8"?> <phpunit> <php> <const name="foo" value="bar"/> <var name="foo" value="bar"/> <ini name="foo" value="bar"/> </php> </phpunit>

PHPUnit Best Practices Disable PHPUnit features (that you should not need anyway)  Syntax Check  Enabled by default in PHPUnit 3.4  Disabled by default in PHPUnit 3.5  Removed in PHPUnit 3.6  Backup/Restore of global variables  Enabled by default in PHPUnit 3.5  Disabled by default in PHPUnit 3.6  Backup/Restore of static attributes  Disabled by default

PHPUnit Best Practices Disable PHPUnit features (that you should not need anyway) <?xml version="1.0" encoding="UTF-8"?> <phpunit backupGlobals="false" backupStaticAttributes="false" syntaxCheck="false"> <testsuites> <testsuite name="My Test Suite"> <directory>path/to/dir</directory> </testsuite> </testsuites> </phpunit>

PHPUnit Best Practices Use Code Coverage Whitelisting <?xml version="1.0" encoding="UTF-8"?> <phpunit backupGlobals="false" backupStaticAttributes="false" syntaxCheck="false"> <filter> <whitelist addUncoveredFilesFromWhitelist="true"> <directory suffix=".php">path/to/dir</directory> </whitelist> </filter> </phpunit>

PHPUnit Best Practices Make the Code Coverage information more meaningful /** * @covers Object_Freezer::freeze */ public function testFreezingAnObjectWorks() { $this->assertEquals( array( /* ... */ ), $this->freezer->freeze(new A(1, 2, 3)) ); }

PHPUnit Best Practices Exploit dependencies between tests /** * @covers Object_Freezer::freeze * @covers Object_Freezer::thaw * @depends testFreezingAnObjectWorks */ public function testFreezingAndThawingAnObjectWorks() { $object = new A(1, 2, 3); $this->assertEquals( $object, $this->freezer->thaw( $this->freezer->freeze($object) ) ); }

PHPUnit Best Practices Decouple test code from test data <?php class DataTest extends PHPUnit_Framework_TestCase { /** * @dataProvider providerMethod */ public function testAdd($a, $b, $c) { $this->assertEquals($c, $a + $b); } public function providerMethod() { return array( array(0, 0, 0), array(0, 1, 1), array(1, 1, 3), array(1, 0, 1) ); } }

The End  Slides: http://talks.thePHP.cc/  Web: http://thePHP.cc/ http://sebastian-bergmann.de/  Mail: sebastian@thePHP.cc  Twitter: @s_bergmann

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Getting Started With PHPUnit

by Sebastian Bergmann on Mar 11, 2010

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Getting Started With PHPUnit — Presentation Transcript