Unit-Testing Bad-Practices by Example

Unit-Testing Bad-Practices
by Example

Benjamin Eberlei
direkt eﬀekt GmbH

August 2009

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

About Me

Benjamin Eberlei
direkt eﬀekt GmBH (digital marketing)
Zend Framework contributor
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 ()
{
Zen d_ C o n t r o l l e r _ Front :: getInstance () ->
s e t C o n t r o l l er Dir ec to ry ( ’/ _files ’) ;
require_once ’/ _files / ViewController . php ’;
$controller = new ViewController (
new Z e n d _ C o n t r o l l e r _ R e q u e s t _ H t t p () ,
new Z e n d _ C o n t r o l l e r _ R e s p o n s e _ C l i ()
);
$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 Z e n d _ C o n t r o l l e r _ R e q u e s t _ H t t p () ;
$request - > set ControllerName ( ’ view ’)
-> setActionName ( ’ test ’) ;
$response = new Z e n d _ C o n t r o l l e r _ R e s p o n s e _ C l i () ;
Zen d_ C o n t r o l l e r _ Front :: getInstance () ->
s e t C o n t r o l l er Dir ec to ry ( ’/ _files ’) ;
$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 c r e ateViewController ( $controllerName = null ,
$actionName = null )
{
$request = new Z e n d _ C o n t r o l l e r _ R e q u e s t _ H t t p () ;
if ( $controllerName !== null ) {
$request - > setControllerName ( $controllerName ) ;
}
if ( $actionName !== null ) {
$request - > setActionName ( $actionName ) ;
}
$response = new Z e n d _ C o n t r o l l e r _ R e s p o n s e _ C l i () ;
Zen d_ C o n t r o l l e r _ Front :: getInstance ()
-> s e t C o n t r o l le rD ire ct or y ( ’/ _files ’) ;

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


ZF Controller Refactoring 2
public function t e s tI nit Vi ew Ref ac to red ()
{
// 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 t e s t R e n d e r B y N a m e R e f a c t o r e d ()
{
// fixture setup
$controller =
$this - > c r e a teViewController ( ’ view ’ , ’ test ’) ;

// execution
$controller - > testAction () ;

// assertions
$this - > assertContains (
’ In the index action view ’ ,
$response - > getBody ()
);
}


Assertion Roulette


Doctrine ResultSetMapping

public function t e s t B a s i c Re s u l t S e t M a p p i n g ()
{
// 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 ’) ;
$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 t e s t R e m o v e O r d e r e d P a r a m e t e r ()
{
$urlCfg = new e zcUrlConfiguration () ;
$urlCfg - > a d dO r d eredParameter ( ’ section ’ ) ;
$urlCfg - > a d dO r d eredParameter ( ’ module ’ ) ;
$urlCfg - > a d dO r d eredParameter ( ’ view ’ ) ;

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

// [..]
}


ezcUrl Test 2
{
// [..]

// functionality tested in other tests before
array ( ’ section ’ = > 0 , ’ module ’ = > 1 , ’ view ’ = > 2) ,
$url - > configuration - > orderedParameters
);
$this - > assertEquals ( ’ doc ’ , $url - > getParam ( ’ section ’) ) ;
’ components ’ , $url - > getParam ( ’ module ’)
);

// [..]
}


ezcUrl Test 3

{
// [..]
// Primary Assertion according to test method name
$url - > configuration - > r em ove Or de re dPa ra me ter ( ’ view ’) ;
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 ( e z c U r l I n v a l i d P a r a m e t e r E x c e p t i o n $e ) {
$expected = " ... " ;
$this - > assertEquals ( $expected , $e - > getMessage () ) ;
}

// [..]?
}


ezcUrl Test 5

{
// [..]
// try removing again - nothing bad should happen
$url - > configuration - > r em ove Or de re dPa ra me ter ( ’ view ’) ;
try
{
$this - > assertEquals ( null , $url - > getParam ( ’ view ’) ) ;
$this - > fail ( ’ Expected exception was not thrown . ’) ;
} catch ( e z c U r l I n v a l i d P a r a m e t e r E x c e p t i o n $e ) {
$expected = " ... " ;
$this - > assertEquals ( $expected , $e - > getMessage () ) ;
}
}


Fragile Test


Zend SOAP Wsdl Test
function 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
// Z e n d _ C o n t r o l l e r _ A c t i o n _ H e l p e r _ V i e w R e n d e r e r T e s t
protected function setUp ()
{
$this - > request = new Z e n d _ C o n t r o l l e r _ R e q u e s t _ H t t p () ;
$this - > response = new Z e n d _ C o n t r o l l e r _ R e s p o n s e _ H t t p () ;
$this - > front = Ze nd_C ontro ller _Fron t :: getInstance ()
;
$this - > front - > resetInstance () ;
$this - > front - > a ddModuleDirectory ( ’/ _files / modules ’)
-> setRequest ( $this - > request )
-> setResponse ( $this - > response ) ;

$this - > helper = new
Z e n d _ C o n t r o l l e r _ A c t i o n _ H e l p e r _ V i e w R e n d e r e r () ;
Z e n d _ C o n t r o l l e r _ A c t i o n _ H e l p e r B r o k e r :: addHelper (
$this - > helper
);
}


Indirect Tests: ezcMvc
function t e s t I n t e r n alRedirect () {
$config = new s impleConfiguration () ;
$config - > route = ’ IRController ’;
$dispatcher = new e z c M v c C o n f i g u r a b l e D i s p a t c h e r (
$config ) ;
$dispatcher - > run () ;
self :: assertEquals ( " BODY : Name : name , " .
" Vars : array ([ CR ] ’ nonRedirVar ’ = > 4 , " .
" [ CR ] ’ ReqRedirVar ’ = > 4 ,[ CR ]) " , $config - > store ) ;
}

function t e s t E x t e r n alRedirect () {
$config = new s impleConfiguration () ;
$config - > route = ’ IRController ’;
$dispatcher = new e z c M v c C o n f i g u r a b l e D i s p a t c h e r (
$config ) ;
$dispatcher - > run () ;
self :: assertEquals ( " BODY : Name : name , " .
" Vars : array ([ CR ] ’ nonRedirVar ’ = > 4 , " .
" [ CR ] ’ ReqRedirVar ’ = > 4 ,[ CR ]) " , $config - > store ) ;
}


Test-Names: FLOW3 MVC
dispatchCallsTheControllersProcess
RequestMethodUntilTheIsDispatchedFlag
InTheRequestObjectIsSet()
dispatchThrowsAnInﬁniteLoopException
IfTheRequestCouldNotBeDispached
After99Iterations()
resolveControllerReturnsTheNotFound
ControllerDeﬁnedInTheFLOW3Settings
AndInjectsCorrectException
IfTheResolvedControllerDoesNotExist()


Slow Tests


Zend Service Amazon
public function setUp ()
{
$this - > _amazon = new Zend_Service_Amazon () ;
$this - > _query = new Z e n d _ S e r v i ce _ A m a z o n _ Q u e r y ()

$this - > _httpClient =
new Z e n d _ H t t p _ C l i e n t _ A d a p t e r _ S o c k e t () ;
$this - > _amazon - > getRestClient ()
-> getHttpClient ()
-> setAdapter ( $this - > _httpClient ) ;

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


Zend Service Amazon 2

public function t e s t I t e m S ea r c h M u s i c M o z a r t ()
{
$resultSet = $this - > _amazon - > itemSearch ( array (
’ SearchIndex ’ = > ’ Music ’ ,
’ Keywords ’ = > ’ Mozart ’ ,
’ ResponseGroup ’ = > ’ Small , Tracks , Offers ’
));
foreach ( $resultSet as $item ) {
$item instanceof Z e n d_ S e r vi c e _ Am a z o n_ I t e m
);
}
}


Zend Amazon Refactored

public function setUpRefactored ()
{
$this - > _amazon = new Zend_Service_Amazon () ;

$this - > _httpClient =
new Z e n d _ H t t p _ C l i e n t _ A d a p t e r _ T e s t () ;

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


Zend Amazon Refactored 2
public function t e s t I t e m S e a r c h M u s i c M o z a r t R e f a c t o r e d ()
{
$this - > _httpClient - > setResponse (
fil e_get_ contents ( " ExpectedTestResponse . txt " )
);

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

foreach ( $resultSet as $item ) {
$item instanceof Z e n d_ S e r vi c e _ Am a z o n_ I t e m
);
// 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 t h e C o n s t r u c t o r A c c e p t s V a l i d I d e n t i f i e r s () {
$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 d a t a A c c e p t V a l i d I d e n t i f ie r
*/
public function c o n s t r u c t o r A c c e p t s V a l i d I d e n t i f i e r ( $id ) {
$mockBackend = $this - > createMockBackend () ;

$abstractCache = $this - > getMock (
’ F3 FLOW3 Cache Frontend StringFrontend ’ ,
array () ,
array ( $id , $mockBackend )
);
}
static public function d a t a A c c e p tV a l i d I d e n t i f i e r () {
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 Z e n d _ S e r v e r _ R e f l e c t i o n _ C l a s s (
new ReflectionClass ( ’ Ze nd_ Se rv er_ Re fl ect io n ’)
);

$methods = $r - > getMethods () ;
$this - > assertTrue ( is_array ( $methods ) ) ;
foreach ( $methods as $m ) {
$m instanceof Z e n d _ S e r v e r _ R e f l e c t i o n _ M e t h o d
);
}
}


A working implementation

class Z e n d _ S e r v e r _ R e f l e c t i o n _ C l a s s ()
{
public function getMethods ()
{
return array () ;
}
}

Great, all tests pass!


Test Refactoring
public function t e s t G e tM e t ho d s R ef a c t or e d ()
{
);

$methods = $r - > getMethods () ;
$this - > assertTrue ( is_array ( $methods ) ) ;
$this - > assertEquals (3 , count ( $methods ) ) ; // (!!)
);
}
}


Test Refactoring 2
public function ass ertReflMethods ( $methods , $expected )
{
$this - > assertTye ( ’ array ’ , $methods ) ;
$this - > assertEquals ( $expected , count ( $methods ) ) ;
);
}
}
public function t e s t G e tM e t ho d s R ef a c t or e d ()
{
);
$this - > as sertRe flMethods ( $r - > getMethods () , 3) ;
}


ezcPersistentObject Relations

public function t e s tIsRelatedSuccess ()
{
$person = $this - > session - > load ( " TestPerson " , 1 ) ;
$addresses = $this - > session - > getRelatedObjects (
$person , ’ TestAddress ’
);

foreach ( $addresses as $address ) {
$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 ) ) ;
-> will ( $this - > returnValue ( FALSE ) ) ;
-> will ( $this - > returnValue ( TRUE ) ) ;

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

// [..]
}


FLOW3 MVC Dispatcher 2
public 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 ( ’
reso lveController ’) ,
array () , ’ ’ , FALSE
);
$dispatcher - > expects ( $this - > any () )
-> method ( ’ resolveController ’)
-> will ( $this - > returnValue ( $mockController ) )
;
$dispatcher - > dispatch ( $mockRequest , $mockResponse ) ;
}


Conclusion

Don’t use global state (Singleton
Anti-Pattern)
Use utility methods for Assertions, Object
and Mock Creation
Use Mocks (but not exclusively)
Give meaningful test-names
Dont test through the UI


Further Readings

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

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


Thank You!

E-Mail: kontakt@beberlei.de
Twitter: beberlei
Slides: http://www.whitewashing.de
PHP Quality Assurance Book, Early 2010!


Unit-Testing Bad-Practices by Example

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