Unit-Testing Bad-Practices by Example

Unit-Testing Bad-Practicesby Example

Benjamin Eberlei

direkt effekt GmbH

August 2009

Eberlei (direkt effekt GmbH) Unit-Testing Bad-Practices August 2009 1 / 49

About Me

I Benjamin Eberlei

I direkt effekt GmBH (digital marketing)

I Zend Framework contributor

I Test-Driven-Development, Legacy Testing


And You?


Why Test Quality Matters



“We spent 90% of the time

modifying existing tests to

acommodate for a relatively

minor change.“

(G. Meszaros, xUnit Test Patterns)


“Walking on water and

developing software from a

specification are easy if both

are frozen.”

(Edward V. Berard)

Safety Net vs Dead Weight


Test Smells


“Smell you later!”

(Nelson, The Simpsons)

Code Duplication


ZF Controller Action

public function testInitView (){

Zend_Controller_Front :: getInstance ()->setControllerDirectory(’/_files ’);

require_once ’/_files/ViewController.php’;$controller = new ViewController(

new Zend_Controller_Request_Http (),new Zend_Controller_Response_Cli ()

);$view = $controller ->initView ();$this ->assertTrue($view instanceof Zend_View);$scriptPath = $view ->getScriptPaths ();$this ->assertTrue(is_array($scriptPath));$this ->assertEquals(’/views/scripts/’, $scriptPath [0])

;}


ZF Controller Action 2

public function testRenderByName (){

$request = new Zend_Controller_Request_Http ();$request ->setControllerName(’view’)

->setActionName(’test’);$response = new Zend_Controller_Response_Cli ();Zend_Controller_Front :: getInstance ()->

setControllerDirectory(’/_files ’);require_once ’/_files/ViewController.php’;$controller = new ViewController($request , $response);

$controller ->testAction ();$this ->assertContains(’In the index action view’,

$response ->getBody ());}


ZF Controller Refactoring

Extract Test Utility Method:public function createViewController($controllerName=null ,

$actionName=null){

$request = new Zend_Controller_Request_Http ();if($controllerName !== null) {

$request ->setControllerName($controllerName);}if($actionName !== null) {

$request ->setActionName($actionName);}$response = new Zend_Controller_Response_Cli ();

Zend_Controller_Front :: getInstance ()->setControllerDirectory(’/_files ’);

require_once ’/_files/ViewController.php’;

return new ViewController($request , $response);}


ZF Controller Refactoring 2

public function testInitViewRefactored (){

// fixture setup$controller = $this ->createViewController ();

// execution$view = $controller ->initView ();$scriptPath = $view ->getScriptPaths ();

// assertions$this ->assertTrue($view instanceof Zend_View);$this ->assertTrue(is_array($scriptPath));$this ->assertEquals(

’/views/scripts/’, $scriptPath [0]);

}


ZF Controller Refactoring 3

public function testRenderByNameRefactored (){

// fixture setup$controller =

$this ->createViewController(’view’, ’test’);

// execution$controller ->testAction ();

// assertions$this ->assertContains(

’In the index action view’,$response ->getBody ()

);}


Assertion Roulette


Doctrine ResultSetMapping

public function testBasicResultSetMapping (){

// Fixture Setup$rsm = new ResultSetMapping ();$rsm ->addEntityResult(

’Doctrine\Tests\Models\CMS\CmsUser ’,’u’

);$rsm ->addFieldResult(’u’, ’id’, ’id’);$rsm ->addFieldResult(’u’, ’status ’, ’status ’);$rsm ->addFieldResult(’u’, ’user’, ’user’);$rsm ->addFieldResult(’u’, ’name’, ’name’);// [..]

}


Doctrine ResultSetMapping 2


// [..]$this ->assertFalse($rsm ->isScalarResult(’id’));$this ->assertFalse($rsm ->isScalarResult(’status ’));$this ->assertFalse($rsm ->isScalarResult(’user’));$this ->assertFalse($rsm ->isScalarResult(’name’));

$this ->assertTrue($rsm ->getClass(’u’) ==’Doctrine\Tests\Models\CMS\CmsUser ’

);$class = $rsm ->getOwningClass(’id’);$this ->assertTrue(

$class == ’Doctrine\Tests\Models\CMS\CmsUser ’);

}


Doctrine ResultSetMapping 3


// [..]$this ->assertEquals(’u’, $rsm ->getAlias(’id’));$this ->assertEquals(’u’, $rsm ->getAlias(’status ’));$this ->assertEquals(’u’, $rsm ->getAlias(’user’));$this ->assertEquals(’u’, $rsm ->getAlias(’name’));

$this ->assertEquals(’id’, $rsm ->getField(’id’));$this ->assertEquals(’status ’, $rsm ->getField(’status ’));$this ->assertEquals(’username ’, $rsm ->getField(’user’));$this ->assertEquals(’name’, $rsm ->getField(’name’));

}


Eager Test


ezcUrl Test

public function testRemoveOrderedParameter (){

$urlCfg = new ezcUrlConfiguration ();$urlCfg ->addOrderedParameter( ’section ’ );$urlCfg ->addOrderedParameter( ’module ’ );$urlCfg ->addOrderedParameter( ’view’ );

$u = ’http :// www.example.com/doc/components ’;$url = new ezcUrl($u, $urlCfg);

//[..]}


ezcUrl Test 2


// [..]

// functionality tested in other tests before$this ->assertEquals(

array(’section ’ => 0, ’module ’ => 1, ’view’ => 2),$url ->configuration ->orderedParameters

);$this ->assertEquals(’doc’, $url ->getParam(’section ’));$this ->assertEquals(

’components ’, $url ->getParam(’module ’));

// [..]}


ezcUrl Test 3


// [..]

// Primary Assertion according to test method name$url ->configuration ->removeOrderedParameter(’view’);$this ->assertEquals(

array( ’section ’ => 0, ’module ’ => 1 ),$url ->configuration ->orderedParameters

);

// [..]?}


ezcUrl Test 4


// [..]

try{

$this ->assertEquals(null , $url ->getParam(’view’));$this ->fail(’Expected exception was not thrown.’);

} catch ( ezcUrlInvalidParameterException $e ) {$expected = "...";$this ->assertEquals($expected , $e->getMessage ());

}

// [..]?}


ezcUrl Test 5


// [..]

// try removing again - nothing bad should happen$url ->configuration ->removeOrderedParameter(’view’);try{

$this ->assertEquals(null , $url ->getParam(’view’));$this ->fail(’Expected exception was not thrown.’);

} catch ( ezcUrlInvalidParameterException $e ) {$expected = "...";$this ->assertEquals($expected , $e->getMessage ());

}}


Fragile Test


Zend SOAP Wsdl Testfunction testAddBinding () {$wsdl = new Zend_Soap_Wsdl(

’MyService ’, ’http :// localhost/MyService.php’);$wsdl ->addPortType(’myPortType ’);$wsdl ->addBinding(’MyServiceBinding ’, ’myPortType ’);

$this ->assertEquals($wsdl ->toXml ()),’<?xml version ="1.0"? >’ .’<definitions xmlns ="http :// schemas.xmlsoap.org/wsdl/" ’. ’xmlns:tns="http :// localhost/MyService.php" ’. ’xmlns:soap="http :// schemas.xmlsoap.org/wsdl/soap/" ’. ’xmlns:xsd="http ://www.w3.org /2001/ XMLSchema" ’. ’xmlns:soap -enc="http :// schemas.xmlsoap.org/soap/

encoding /" ’. ’xmlns:wsdl="http :// schemas.xmlsoap.org/wsdl/" ’. ’name=" MyService" targetNamespace ="http :// localhost/

MyService.php">’. ’<portType name=" myPortType "/>’. ’<binding name=" MyServiceBinding" type=" myPortType "/>’

. ’</definitions >’ );}


Obscure Tests


Global State: Zend Framework

// Zend_Controller_Action_Helper_ViewRendererTestprotected function setUp(){

$this ->request = new Zend_Controller_Request_Http ();$this ->response = new Zend_Controller_Response_Http ();$this ->front = Zend_Controller_Front :: getInstance ()

;$this ->front ->resetInstance ();$this ->front ->addModuleDirectory(’/_files/modules ’)

->setRequest($this ->request)->setResponse($this ->response);

$this ->helper = newZend_Controller_Action_Helper_ViewRenderer ();

Zend_Controller_Action_HelperBroker :: addHelper($this ->helper

);}


Indirect Tests: ezcMvcfunction testInternalRedirect () {

$config = new simpleConfiguration ();$config ->route = ’IRController ’;$dispatcher = new ezcMvcConfigurableDispatcher(

$config );$dispatcher ->run();self:: assertEquals("BODY: Name: name , ".

"Vars: array ([CR] ’nonRedirVar ’ => 4,"."[CR] ’ReqRedirVar ’ => 4,[CR])", $config ->store);

}

function testExternalRedirect () {$config = new simpleConfiguration ();$config ->route = ’IRController ’;$dispatcher = new ezcMvcConfigurableDispatcher(

$config );$dispatcher ->run();self:: assertEquals("BODY: Name: name , ".

"Vars: array ([CR] ’nonRedirVar ’ => 4,"."[CR] ’ReqRedirVar ’ => 4,[CR])", $config ->store);

}


Test-Names: FLOW3 MVC

I dispatchCallsTheControllersProcessRequestMethodUntilTheIsDispatchedFlagInTheRequestObjectIsSet()

I dispatchThrowsAnInfiniteLoopExceptionIfTheRequestCouldNotBeDispachedAfter99Iterations()

I resolveControllerReturnsTheNotFoundControllerDefinedInTheFLOW3SettingsAndInjectsCorrectExceptionIfTheResolvedControllerDoesNotExist()


Slow Tests


Zend Service Amazon

public function setUp (){

$this ->_amazon = new Zend_Service_Amazon ();$this ->_query = new Zend_Service_Amazon_Query ()

$this ->_httpClient =new Zend_Http_Client_Adapter_Socket ();

$this ->_amazon ->getRestClient ()->getHttpClient ()->setAdapter($this ->_httpClient);

// terms of use compliance:// no more than one query per secondsleep (1);

}


Zend Service Amazon 2

public function testItemSearchMusicMozart (){

$resultSet = $this ->_amazon ->itemSearch(array(’SearchIndex ’ => ’Music ’,’Keywords ’ => ’Mozart ’,’ResponseGroup ’ => ’Small ,Tracks ,Offers ’

));

foreach ($resultSet as $item) {$this ->assertTrue(

$item instanceof Zend_Service_Amazon_Item);

}}


Zend Amazon Refactored

public function setUpRefactored (){

$this ->_amazon = new Zend_Service_Amazon ();

$this ->_httpClient =new Zend_Http_Client_Adapter_Test ();

$this ->_amazon ->getRestClient ()->getHttpClient ()->setAdapter($this ->_httpClient);

}


Zend Amazon Refactored 2

public function testItemSearchMusicMozartRefactored (){

$this ->_httpClient ->setResponse(file_get_contents("ExpectedTestResponse.txt")

);

$resultSet = $this ->_amazon ->itemSearch(array(’SearchIndex ’ => ’Music ’,’Keywords ’ => ’Mozart ’,’ResponseGroup ’ => ’Small ,Tracks ,Offers ’

));

foreach ($resultSet as $item) {$this ->assertTrue(

$item instanceof Zend_Service_Amazon_Item);// Assert some relevant stuff now!

}}


Conditional Logic

“Everyone knows that debugging is

twice as hard as writing a program in

the first place. So if you’re as clever as

you can be when you write it, how will

you ever debug it?” (Brian Kernighan)


FLOW3 Cache Frontend

public function theConstructorAcceptsValidIdentifiers () {$mockBackend = $this ->createMockBackend ();

$identifiers = array(’x’, ’someValue ’, ’123 fivesixseveneight ’,’some&’, ’ab_cd%’,rawurlencode(’package :// some/ $ &% sadf’),str_repeat(’x’, 250)

);

foreach ($identifiers as $identifier) {$abstractCache = $this ->getMock(

’F3\FLOW3\Cache\Frontend\StringFrontend ’,array(),array($identifier , $mockBackend)

);}

}


FLOW3 Cache Refactored/*** @dataProvider dataAcceptValidIdentifier*/

public function constructorAcceptsValidIdentifier($id) {$mockBackend = $this ->createMockBackend ();

$abstractCache = $this ->getMock(’F3\FLOW3\Cache\Frontend\StringFrontend ’,array(),array($id , $mockBackend)

);}static public function dataAcceptValidIdentifier () {

return array(array(’x’), array(’someValue ’),array(’123 fivesixseveneight ’),array(’some&’), array(’ab_cd%’),array(

rawurlencode(’package :// some/ $ &% sadf’)),array(str_repeat(’x’, 250))

);}


Zend Server ReflectionClass

public function testGetMethods (){

$r = new Zend_Server_Reflection_Class(new ReflectionClass(’Zend_Server_Reflection ’)

);

$methods = $r->getMethods ();$this ->assertTrue(is_array($methods));foreach ($methods as $m) {

$this ->assertTrue($m instanceof Zend_Server_Reflection_Method

);}

}


A working implementation

class Zend_Server_Reflection_Class (){

public function getMethods (){

return array ();}

}

Great, all tests pass!


Zend Server ReflectionClassTest Refactoring

public function testGetMethodsRefactored (){


);

$methods = $r->getMethods ();$this ->assertTrue(is_array($methods));$this ->assertEquals (3, count($methods)); // (!!)foreach ($methods as $m) {


);}

}


Zend Server ReflectionClassTest Refactoring 2

public function assertReflMethods($methods , $expected){

$this ->assertTye(’array ’, $methods);$this ->assertEquals($expected , count($methods));foreach ($methods as $m) {


);}

}public function testGetMethodsRefactored (){


);$this ->assertReflMethods($r->getMethods (), 3);

}


ezcPersistentObject Relations

public function testIsRelatedSuccess (){

$person = $this ->session ->load( "TestPerson", 1 );$addresses = $this ->session ->getRelatedObjects(

$person , ’TestAddress ’);

foreach ( $addresses as $address ) {$this ->assertTrue(

$this ->session ->isRelated( $person , $address ));

}}


Mock-Overkill


FLOW3 MVC Dispatcher

public function testDispatch () {$mockRequest = $this ->getMock(’F3\FLOW3\MVC\

RequestInterface ’);$mockRequest ->expects($this ->at(0))

->method(’isDispatched ’)->will($this ->returnValue(FALSE));

$mockRequest ->expects($this ->at(1))->method(’isDispatched ’)->will($this ->returnValue(FALSE));

$mockRequest ->expects($this ->at(2))->method(’isDispatched ’)->will($this ->returnValue(TRUE));

$mockResponse = $this ->getMock(’F3\FLOW3\MVC\ResponseInterface ’

);

// [..]}


FLOW3 MVC Dispatcher 2public function testDispatch () {

// [..]$mockController = $this ->getMock(

’F3\FLOW3\MVC\Controller\ControllerInterface ’,array(’processRequest ’, ’canProcessRequest ’)

);$mockController ->expects($this ->exactly (2))

->method(’processRequest ’)->with($mockRequest , $mockResponse);

$dispatcher = $this ->getMock(’F3\FLOW3\MVC\Dispatcher ’, array(’

resolveController ’),array(), ’’, FALSE

);$dispatcher ->expects($this ->any())

->method(’resolveController ’)->will($this ->returnValue($mockController))

;$dispatcher ->dispatch($mockRequest , $mockResponse);

}


Conclusion

I Don’t use global state (Singleton

Anti-Pattern)

I Use utility methods for Assertions, Object

and Mock Creation

I Use Mocks (but not exclusively)

I Give meaningful test-names

I Dont test through the UI


Further Readings

I xUnit Test Patterns

Book by Gerald Meszaros, http://xunitpatterns.com/Test%20Smells.html

I TDD Anti Patterns

http://blog.james-carr.org/2006/11/03/tdd-anti-patterns/


Thank You!

E-Mail: [email protected]

Twitter: beberlei

Slides: http://www.whitewashing.de

PHP Quality Assurance Book, Early 2010!


Unit-Testing Bad-Practices by Example

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