Unit Test Fun

Unit Test Fun: Mock Objects, Fixtures,
Stubs & Dependency Injection

Max Köhler I 02. Dezember 2010

© 2010 Mayﬂower GmbH

Wer macht UnitTests?

Unit Test Fun: Mock Objects, Fixtures, Stubs & Dependency Injection I Mayﬂower GmbH I 02. Dezember 2010 I 2

Code Coverage?


Wer glaubt, dass die Tests
gut sind?


Kann die Qualität
gesteigert werden?
100%

0%

Test der kompletten
Architektur?


MVC?
Controller

View Model


Wie testet Ihr eure
Models?


Direkter DB-Zugriff?


Keine UnitTests!

STOP


Integration Tests!


Wie testet Ihr eure
Controller?


Routes, Auth-Mock,
Session-Mock, ...?


Keine UnitTests!

STOP


Was wollen wir testen?


Integration Regression
Testing Testing

Unit Testing

System - Integration
Testing
Acceptance
Testing

System Testing


The goal of unit testing is
to isolate each part of the
program and show that
the individual parts are
correct


Test Doubles


Stubs


Fake that returns
canned data...


Beispiel für ein Auth-Stub

$storageData = array(
'accountId' => 29,
'username' => 'Hugo',
'jid' => 'hugo@example.org');

$storage = $this->getMock('Zend_Auth_Storage_Session', array('read'));
$storage->expects($this->any())
->method('read')
->will($this->returnValue($storageData));

Zend_Auth::getInstance()->setStorage($storage);

// ...

/*
* Bei jedem Aufruf wird nun das Mock als Storage
* verwendet und dessen Daten ausgelesen
*/
$session = Zend_Auth::getInstance()->getIdentity();


Mocks


Spy with
expectations...


Model Mapper Beispiel

class Application_Model_GuestbookMapper
{
protected $_dbTable;

public function setDbTable(Zend_Db_Table_Abstract $dbTable)
{
$this->_dbTable = $dbTable;
return $this;
}

public function getDbTable()
{
return $this->_dbTable;
}

public function getEmail() {}
public function getComment() {}

public function save(Application_Model_Guestbook $guestbook)
{
$data = array(
'email' => $guestbook->getEmail(),
'comment' => $guestbook->getComment(),
);

$this->getDbTable()->insert($data);
}
}


Testen der save() Funktion

class Applicatoin_Model_GuestbookMapperTest extends PHPUnit_Framework_TestCase
{
public function testSave()
{
$modelStub = $this->getMock('Application_Model_Guestbook', array('getEmail', ,getComment'));

$modelStub->expects($this->once())
->method('getEmail')
->will($this->returnValue('super@email.de'));

$modelStub->expects($this->once())
->method('getComment')
->will($this->returnValue('super comment'));

$tableMock = $this->getMock('Zend_Db_Table_Abstract', array('insert'), array(), '', false);
$tableMock->expects($this->once())
->method('insert')
->with($this->equalTo(array(
'email' => 'super@email.de',
'comment' => 'super comment')));

$model = new Application_Model_GuestbookMapper();
$model->setDbTable($tableMock); // << MOCK
$model->save($modelStub); // << STUB
}
}


Stub Mock
Fake that Spy with
returns canned !== expectations...
data...


Fixtures


Set the world up
in a known
state ...


Fixture-Beispiel

class Fixture extends PHPUnit_Framework_TestCase
{
protected $fixture;

protected function setUp()
{
$this->fixture = array();
}

public function testEmpty()
{
$this->assertTrue(empty($this->fixture));
}

public function testPush()
{
array_push($this->fixture, 'foo');
$this->assertEquals('foo', $this->fixture[0]);
}

public function testPop()
{
array_push($this->fixture, 'foo');
$this->assertEquals('foo', array_pop($this->fixture));
$this->assertTrue(empty($this->fixture));
}
}


Method Stack

Ablauf

public static function setUpBeforeClass() { }

protected function setUp() { }

public function testMyTest() { /* TEST */ }

protected function tearDown() { }

protected function onNotSuccessfulTest(Exception $e) { }

public static function tearDownAfterClass() { }


Test Suite ...


...wirkt sich auf die
Architektur aus.


Wenn nicht...


Developer

Titel der Präsentation I Mayﬂower GmbH I xx. Juni 2010 I 34

Was kann man machen?


Production Code
überarbeiten


Dependency Injection


Bemerkt?


Dependency Injection

class Application_Model_GuestbookMapper
{
protected $_dbTable;

public function setDbTable(Zend_Db_Table_Abstract $dbTable)
{
$this->_dbTable = $dbTable;
return $this;
}

public function getDbTable()
{
return $this->_dbTable;
}

public function getEmail() {}
public function getComment() {}

public function save(Application_Model_Guestbook $guestbook)
{
$data = array(
'email' => $guestbook->getEmail(),
'comment' => $guestbook->getComment(),
);

$this->getDbTable()->insert($data);
}
}


Besser aber ...


... Begeisterung sieht anders aus!


Was könnte noch helfen?


TDD?
Test Driven Development

[
~~
[ ~~
~~ ~~
~~ ~~
~~ ~~
~

Probleme früh erkennen!


Uncle Bob´s
Three Rules of TDD


#1
“ You are not allowed to write any

production code unless it is to make a
failing unit test pass.


#2
“ You are not allowed to write any more of

a unit test than is sufﬁcient to fail; and
compilation failures are failures.


#3
“ You are not allowed to write any more

production code than is sufﬁcient to pass
the one failing unit test.


Und wieder...


Developer


Und jetzt?


Things get worst
before they get
better !


Monate später...


Gibts noch was?


Darf ich vorstellen:
„Bug“


Regression Testing
or
Test your Bugs!


Regression Testing

Bug
class Calculate
{
public function divide($dividend, $divisor)
1 {
return $dividend / $divisor;
}
}

2 Warning: Division by zero in /srv/phpunit-slides/Calculate.php on line 7


Regression Testing

Test First!
/**
* Regression-Test BUG-123
*
* @group BUG-123
*
* @return void
3 */
public function testDivideByZero()
{
$calc = new Calculate();
$this->assertEquals(0, $calc->divide(1, 0));
}


Regression Testing

Bugﬁx

class Calculate
{
4 public function divide($dividend, $divisor)
{
if (0 == $divisor) {
return 0;
}
return $dividend / $divisor;
}
}


Regression Testing

phpunit

slides$ phpunit --colors --verbose CalculateTest.php
PHPUnit 3.5.5 by Sebastian Bergmann.
5
CalculateTest
......

Time: 0 seconds, Memory: 5.25Mb

OK (6 tests, 6 assertions)


Regression Testing

@group
slides$ phpunit --colors --verbose --group BUG-123 CalculateTest.php
PHPUnit 3.5.5 by Sebastian Bergmann.
?
CalculateTest
.

Time: 0 seconds, Memory: 5.25Mb

OK (1 tests, 1 assertions)

/**
* Regression-Test BUG-123
*
* @group BUG-123
*
* @return void
? */
public function testDivideByZero()
{


Noch Fragen?


Quellen

I Baby: ADDROX http://www.flickr.com/photos/addrox/2587484034/sizes/m/
I Fish: ADDROX http://www.flickr.com/photos/addrox/274632284/sizes/m/
I Happy: ADDROX http://www.flickr.com/photos/addrox/2610064689/sizes/m/
I Bug: ADDROX http://www.flickr.com/photos/addrox/284649644/sizes/m/


Vielen Dank für Ihre Aufmerksamkeit!

Kontakt Max Köhler
max.koehler@mayflower.de
+49 89 242054-1160

Mayflower GmbH
Mannhardtstr. 6
80538 München

© 2010 Mayﬂower GmbH

Unit Test Fun

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