Understanding The Helter Skelter World of Building Testable PHP Applications

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January 18, 2014 Understanding The Helter Skelter World of Building Testable PHP Applications by Chris Hartjes - SkiPHP 2014

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01 Who is the guy?

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2002

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Some apps will resist our efforts

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So what can we do?

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It’s About Tools

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It’s About Strategies

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WHAT DOES TESTABLE CODE LOOK LIKE?

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✤ Single-purpose objects! ✤ Loose coupling! ✤ Consistency in architectural decisions

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✤ Desired functionality clearer! ✤ Less methods to test! ✤ More likely to be easily extendable

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“Simple systems can display complex behaviour but complex systems can only display simple behaviour.” – Chris Hartjes

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“It's called the Onion Architecture and its main principal is this: organize the layers of your application code like the layers of an onion. Every layer of the onion is only coupled (or dependent upon) any layer deeper in the onion than itself.” –Kristopher Wilson http://kristopherwilson.com/2013/07/04/implementing-the-onion- architecture-in-php/

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“Inside every large program is a small program struggling to get out.” – Hoare’s Law of Large Programs

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“Your framework should be an implementation detail, not a giant killer squid, sucking the life out your application.” – Chris Hartjes

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The Law of Demeter “The Law of Demeter for functions states that any method of an object should call only methods belonging to itself, any parameters that were passed in to the method, any objects it created, and any directly held component objects.”

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“Also known more commonly as! ‘passing in a parameter’” –Chris Hartjes

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Dependency Injection “Pass objects and their methods! other objects that are required.”

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getUri()] >= $_SESSION['user_level']);! }! }! ! // Meanwhile inside your controller! $acl = new \Grumpy\Acl();! ! if (!$acl->accessAllowed()) { ! \Grumpy\View::render('access_denied.tmpl');! } else { ! \Grumpy\View::render('show_stolen_cc.tmpl');! }

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_request = $request;! ! ! $this->_userLevel = $userLevel;! ! }! }! ! // Meanwhile inside your controller! $acl = new \Grumpy\Acl($this->request, $_SESSION['user_level']);! ! if (!$acl->accessAllowed()) { ! ! \Grumpy\View::render('access_denied.tmpl');! } else { ! ! \Grumpy\View::render('show_stolen_cc.tmpl');! }

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_request = $value;! ! }! ! ! public function setUserLevel($value)! ! {! ! ! $this->_userLevel = $value;! ! }! }! ! // Meanwhile inside your controller...! $acl = new \Grumpy\Acl();! $acl->setRequest($this->_request);! $acl->setUserLevel($_SESSION['user_level']);! ! if (!$acl->accessAllowed()) {! ! \Grumpy\View::render('access_denied.tmpl');! } else {! ! \Grumpy\View::render('show_stolen_cc.tmpl');! }

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Test Doubles ✤ create copies of existing objects for testing purposes! ✤ essential for effective unit testing

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✤ Database connections! ✤ Web services! ✤ File system operations! ✤ Other objects our test-under-code needs to use

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✤ PHPUnit’s built-in support! ✤ Mockery ! ✤ Prophecy

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getMockBuilder('\Grumpy\Controller\Request')! ! ! ! ->disableOriginalConstructor()! ! ! ! ->getMock();! ! ! $mockRequest->expects($this->once))! ! ! ! ->method('getUri')! ! ! ! ->will($this->returnValue('/account/purge'));! ! ! $testUserLevel = 'admin';! ! ! $acl = new \Grumpy\Acl($mockRequest, $testUserLevel);! ! ! ! $this->assertTrue(! ! ! ! $acl->accessAllowed(),! ! ! ! 'admin user should have access to purge accounts'! ! ! );! ! }! }

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Protected and Private Methods “Protected and ! private methods and! attributes are difﬁcult! to test properly.”

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Etsy’s PHPUnit Extensions! https://github.com/etsy/phpunit-extensions Uses annotations to ﬂag! methods you wish to test

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class ObjectWithPrivate {! ! ! private function myInaccessiblePrivateMethod()! ! {! ! ! return 'inaccessible';! ! }! ! ! /** @accessibleForTesting */! ! private function myAccessiblePrivateMethod() {! ! ! return 'accessible';! ! }! }!

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class ObjectWithPrivateTest extends PHPUnit_Framework_Testcase! {! ! public $accessible;! ! ! public function setUp()! ! {! ! ! parent::setUp();! ! ! $this->accessible = new PHPUnit_Extensions_Helper_AccessibleObject(! ! ! ! new ObjectWithPrivate());! ! }! ! ! public function testMyAccessiblePrivateMethod()! ! {! ! ! $this->assertEquals(! ! ! ! 'accessible',! ! ! ! $this->accessible->myAccessiblePrivateMethod()! ! ! );! ! }! }!

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PHP’S Reﬂection API! ! http://www.gpug.ca/2012/06/02/testing-protected-methods- with-phpunit/

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class Foo! {! ! protected $_message;! ! ! protected function _bar()! ! {! ! ! $this->_message = 'WRITE TESTS OR I CUT YOU';! ! }! }!

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class FooTest extends PHPUnit_Framework_Testcase()! {! ! public function testProtectedBar()! ! {! ! ! $testFoo = new Foo();! ! ! $expectedMessage = 'WRITE TESTS OR I CUT YOU';! ! ! $reflectedFoo = new \ReflectionMethod($testFoo, '_bar');! ! ! $reflectedFoo->setAccessible(true);! ! ! $reflectedFoo->invoke($testFoo);! ! ! $testMessage = PHPUnit_Framework_Assert::readAttribute(! ! ! ! $testFoo,! ! ! ! '_message')! ! ! $this->assertEquals(! ! ! ! $expectedMessage,! ! ! ! $testMessage,! ! ! ! "Did not get expected message"! ! ! );! ! ! }! }!

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“I suggest never testing private or protected methods directly. Instead, test public methods and use code coverage information to make sure they are executed.” –Chris Hartjes

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Databases In Unit Tests “I will just create! a database for! testing purposes!”

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“If you use a database in your unit tests, you are simply testing that your database works. It better work or else you are screwed.” –Chris Hartjes

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class Bar! {! ! public function getBazById($id)! ! {! ! ! $this->db->query("SELECT * FROM baz WHERE id = :bazId");! ! ! $this->db->bind('bazId', $id);! ! ! $results = $this->db->execute();! ! ! $bazList = array();! ! ! ! if (count($results) > 0) {! ! ! ! foreach ($results as $result) {! ! ! ! ! $bazList[] = $result;! ! ! ! }! ! ! }! ! ! ! return $bazList;! ! }! }!

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class BarTest extends PHPUnit_Framework_Testcase! {! ! public function testGetBazById()! ! {! ! ! $bazId = 666;! ! ! $expectedResults= array(1, 2, 3, 4, 5);! ! ! ! $mockDb = $this->getMockBuilder('\Grumpy\Db')! ! ! ! ->disableOriginalConstructor()! ! ! ! ->setMethods(array('query', 'execute', 'bind'))! ! ! ! ->getMock();! ! ! $mockDb->expects($this->once())! ! ! ! ->method('query');! ! ! $mockDb->expects($this->once())! ! ! ! ->method('bind');! ! ! $mockDb->expects($this->once())! ! ! ! ->method('execute')! ! ! ! ->will($this->returnValue($testResults));! ! ! ! // Actual test! ! ! (…)! ! }! }!

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class BarTest extends PHPUnit_Framework_Testcase! {! ! public function testGetBazById()! ! {! ! ! (…)! ! ! // Test setup above! ! ! ! ! ! $testBar = new Bar();! ! ! $testBar->setDb($mockDb);! ! ! $testResults = $testBar->getBazById($bazId);! ! ! ! $this->assertEquals(! ! ! ! $expectedResults,! ! ! ! $testResults,! ! ! ! 'Did not get expected baz result set'! ! ! );! ! }! }!

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API Calls

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_call('/api/bands', $this->_apiKey);! ! }! }! ! class HipsterApiWrapper! {! ! public function __construct($hipsterApi)! ! {! ! ! $this->_hipsterApi = $hipsterApi;! ! }! ! ! public function getBands()! ! {! ! ! return $this->_hipsterApi->getBands();! ! }! }!

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class HipsterApiTest extends PHPUnit_Framework_Testcase! {! ! public function testGetBands()! ! {! ! ! $hipsterApiData = "[{'id': 17, 'Anonymous'}, {'id': 93, 'HipStaar'}]";! ! ! $mockHipsterApi = $this->getMockBuilder('HipsterApi')! ! ! ! ->disableOriginalConstructor()! ! ! ! ->getMock();! ! ! $mockHipsterApi->expects($this->once())! ! ! ! ->with('getBands')! ! ! ! ->will($this->returnValue($hipsterApiData));! ! ! $expectedData = json_decode($hipsterApiData);! ! ! ! // Test follows! ! ! (…)! ! ! }! }!

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class HipsterApiTest extends PHPUnit_Framework_Testcase! {! ! public function testGetBands()! ! {! ! ! (…)! ! ! // Test setup above! ! ! ! $hipsterApiWrapper = new HipsterApiWrapper($mockHipsterApi);! ! ! $testData = $hipsterApiWrapper->getBands();! ! ! ! ! ! ! $this->assertEquals(! ! ! ! $expectedData,! ! ! ! $testData,! ! ! ! 'Did not get expected getBands() result from HipsterApi'! ! ! );! ! }! }

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Environmental Concerns “Your app shouldn’t! care what environment! it runs in.”

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✤ PHPDotEnv (https://github.com/vlucas/phpdotenv)! ✤ Old-school INI ﬁles in their own VCS repo

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“Where did you learn! about all this stuff?!?”!

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http://grumpy-testing.com

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http://grumpy-phpunit.com

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http://grumpy-learning.com

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THANK YOU! ✤ Twitter -> @grmpyprogrammer! ✤ Email -> [email protected]! ✤ IRC -> #phpmentoring on Freenode! ✤ https://joind.in/10440