Testing untestable code

Testing untestable code About me  Stephan Hochdörfer, bitExpert AG  Department Manager Research Labs  enjoying PHP since 1999  S.Hochdoerfer@bitExpert.de  @shochdoerfer

Testing untestable code No excuse for writing bad code!

Testing untestable code Not to freak out!

Testing untestable code Creativity matters!

Testing untestable code "There is no secret to writing tests, there are only secrets to write testable code!" Miško Hevery

Testing untestable code What is „untestable Code“?

Testing untestable code 1. Wrong object construction “new” is evil! s

Testing untestable code 2. Tight coupling

Testing untestable code No code reuse!

Testing untestable code No isolation → not testable!

Testing untestable code 3. Uncertainty

Testing untestable code "...our test strategy requires us to have more control [...] of the sut." Gerard Meszaros, xUnit Test Patterns: Refactoring Test Code

Testing untestable code In a perfect world... Unittest Unittest SUT SUT

Testing untestable code Legacy code is not perfect... Dependency Dependency Unittest Unittest SUT SUT Dependency Dependency

Testing untestable code ... Legacy code is not perfect... Dependency Dependency Unittest Unittest SUT SUT Dependency Dependency ...

Testing untestable code How to get „testable“ code?

Testing untestable code How to get „testable“ code? Refactoring

Testing untestable code "Before you start refactoring, check that you have a solid suite of tests." Martin Fowler, Refactoring

Testing untestable code Hope? - Nope...

Testing untestable code Which path to take?

Testing untestable code Which path to take? Do not change existing code!

Testing untestable code Examples Object Construction External resources Language issues

Testing untestable code Object construction <?php class Car { private $Engine; public function __construct($sEngine) { $this->Engine = Engine::getByType($sEngine); } }

Testing untestable code Object construction - Autoload <?php function run_autoload($psClass) { $sFileToInclude = strtolower($psClass)..php; if(strtolower($psClass) == engine) { $sFileToInclude = /custom/mocks/. $sFileToInclude; } include($sFileToInclude); } // Testcase spl_autoload_register(run_autoload); $oCar = new Car(Diesel);

Testing untestable code Object construction <?php include(Engine.php); class Car { private $Engine; public function __construct($sEngine) { $this->Engine = Engine::getByType($sEngine); } }

Testing untestable code Object construction - include_path <?php ini_set(include_path, /custom/mocks/.PATH_SEPARATOR. ini_get(include_path)); // Testcase include(car.php); $oCar = new Car(Diesel); echo $oCar->run();

Testing untestable code Object construction – Stream Wrapper <?php class CustomWrapper { private $_handler; function stream_open($path, $mode, $options, &$opened_path) { stream_wrapper_restore(file); // @TODO: modify $path before fopen $this->_handler = fopen($path, $mode); stream_wrapper_unregister(file); stream_wrapper_register(file, CustomWrapper); return true; } }

Testing untestable code Object construction – Stream Wrapper stream_wrapper_unregister(file); stream_wrapper_register(file, CustomWrapper);

Testing untestable code Object construction – Stream Wrapper <?php class CustomWrapper { private $_handler ; function stream_read( $count ) { $content = fread($this->_handler, $count ); $content = str_replace (Engine::getByType , Abstract Engine::get , $content ); return $content ; } }

Testing untestable code Object construction – Namespaces <?php class Car { private $Engine; public function __construct($sEngine) { $this->Engine = CarEngine:: getByType($sEngine); } }

Testing untestable code External resources

Testing untestable code External resources Database Webservice Filesystem Mailserver

Testing untestable code External resources – Mock database

Testing untestable code External resources – Mock database Provide own implementation

Testing untestable code External resources – Mock database ZF example: $db = new Custom_Db_Adapter(array()); Zend_Db_Table::setDefaultAdapter($db);

Testing untestable code External resources – Mock database PHPUnit_Extensions_Database_TestCase

Testing untestable code External resources – Mock database Proxy for your SQL Server

Testing untestable code External resources – Mock webservice

Testing untestable code External resources – Mock webservice Provide own implementation

Testing untestable code External resources – Mock webservice Host redirect via /etc/hosts

Testing untestable code External resources – Mock filesystem

Testing untestable code External resources – Mock filesystem <?php // set up test environmemt vfsStream::setup(exampleDir); // create directory in test enviroment mkdir(vfsStream::url(exampleDir)./sample/); // check if directory was created echo vfsStreamWrapper::getRoot()->hasChild(sample);

Testing untestable code External resources – Mock Mailserver

Testing untestable code External resources – Mock Mailserver Use fake mail server

Testing untestable code External resources – Mock Mailserver $ cat /etc/php5/php.ini | grep sendmail_path sendmail_path=/usr/local/bin/logmail $ cat /usr/local/bin/logmail cat >> /tmp/logmail.log

Testing untestable code Dealing with language issues

Testing untestable code Dealing with language issues Testing your privates?

Testing untestable code Dealing with language issues <?php class CustomWrapper { private $_handler; function stream_read($count) { $content = fread($this->_handler, $count); $content = str_replace( private function, public function, $content ); return $content; }

Testing untestable code Dealing with language issues $myClass = new MyClass(); $reflectionClass = new ReflectionClass(MyClass); $reflectionMethod = $reflectionClass-> getMethod(mydemo); $reflectionMethod->setAccessible(true); $reflectionMethod->invoke($myClass);

Testing untestable code Dealing with language issues Overwrite internal functions?

Testing untestable code Dealing with language issues pecl install runkit-0.9

Testing untestable code Dealing with language issues - Runkit <?php ini_set(runkit.internal_override, 1); runkit_function_redefine(mail,,return true;); ?>

Testing untestable code Dealing with language issues pecl install funcall-0.3.0alpha

Testing untestable code Dealing with language issues - Funcall <?php function my_func($arg1, $arg2) { return $arg1.$arg2; } function post_cb($args,$result,$process_time) { // return custom result based on $args } fc_add_post(my_func,post_cb); var_dump(my_func(php, c));

Testing untestable code What else?

Testing untestable code What else? Generative Programming

Testing untestable code Generative Programming Configuration Configuration 1 ... n Implementation Implementation Generator Generator Product components components Product Generator Generator application application

Testing untestable code Generative Programming Configuration Configuration Application Application Implementation Implementation Generator Generator components components Testcases Testcases Generator Generator application application

Testing untestable code Generative Programming A frame is a data structure for representing knowledge.

Testing untestable code A Frame instance <?php class Car { private $Engine; public function __construct($sEngine) { $this->Engine = <!{Factory}!>:: getByType($sEngine); } }

Testing untestable code The Frame controller public class MyFrameController extends SimpleFrameController { public void execute(Frame frame, FeatureConfig config) { if(config.hasFeature("unittest")) { frame.setSlot("Factory", "FactoryMock"); } else { frame.setSlot("Factory", "EngineFactory"); } } }

Testing untestable code Generated result - Testcase <?php class Car { private $Engine; public function __construct($sEngine) { $this->Engine = FactoryMock:: getByType($sEngine); } }

Testing untestable code Generated result - Application <?php class Car { private $Engine; public function __construct($sEngine) { $this->Engine = EngineFactory:: getByType($sEngine); } }

Testing untestable code What is possible?

Testing untestable code What is possible? Show / hide parts of the code

Testing untestable code What is possible? Change content of global vars!

Testing untestable code What is possible? Define pre- or postfixes!

Testing untestable code Is it worth it?

Testing untestable code Conclusions Change your mindset to write testable code!

Testing untestable code Conclusions PHP is a swiss-army knife. Use it that way!

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Testing untestable code Bildquellen http://www.flickr.com/photos/andresrueda/3452940751/ http://www.flickr.com/photos/andresrueda/3455410635/

Testing untestable code - phpconpl11

by Stephan Hochdörfer on Oct 23, 2011

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Testing untestable code - phpconpl11 Presentation Transcript