Building Testable PHP Applications

Slides from Midwest PHP 2013

Transcript

1. Building Testable
   PHP Applications
   Chris Hartjes
   MidwestPHP 2013 - Mar. 3, 2013
   @grmpyprogrammer
   

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2. Text
   Story
   Time
   

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3. WHY DO WE TEST?
   Because programming
   is hard
   

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4. WHY DO WE TEST?
   

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5. A HUGE TOPIC
   

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6. UNCOMFORTABLE TRUTHS
   Some of this
   will not make
   sense to you
   

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7. UNCOMFORTABLE TRUTHS
   Some applications
   will resist all
   attempts to test
   

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8. UNCOMFORTABLE TRUTHS
   Testing is good
   Testable applications
   are better
   

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9. SO WHAT CAN WE DO?
   

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10. IT’S ABOUT TOOLS
    

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11. IT’S ABOUT STRATEGIES
    

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12. AUTOMATION IS KEY
    

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13. AUTOMATION IS KEY
    “Write a script that will
    run all your tests before
    you go live”
    

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14. AUTOMATION
    “Tell your version
    control system to
    run your tests
    on commit or push”
    

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15. AUTOMATION IS KEY
    http://jenkins-ci.org
    http://travis-ci.org
    

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16. ARCHITECTURE
    “Simple systems can
    display complex behavior
    but complex systems can
    only display simple
    behaviour”
    

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17. ARCHITECTURE
    “Inside every great
    large application are
    many great small
    applications”
    

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18. ARCHITECTURE
    “Your framework
    is a detail, not
    the core of your
    application.”
    -- Bob Martin
    

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19. 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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20. DEPENDENCY INJECTION
    “Pass objects and their methods
    other objects and function that are
    required for the task.”
    

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21. DEPENDENCY INJECTION
    namespace Grumpy;
    class Acl {
    protected $_acls; ...
    public function accessAllowed()
    {
    $request = \Grumpy\Context::getRequest();
    return ($acls[$request->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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22. DEPENDENCY INJECTION
    namespace Grumpy;
    class Acl
    {
    ! protected $_acls;
    ! protected $_request;
    ! protected $_userLevel;
    ! ...
    ! public function __construct($request, $userLevel)!
    ! {
    ! ! ...
    ! !
    ! ! $this->_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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23. DEPENDENCY INJECTION
    namespace Grumpy;
    class Acl
    {
    ! ...
    ! public function setRequest($value)
    ! {
    ! ! $this->_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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24. MOCK OBJECTS
    “Mock objects allow you
    to test code in proper
    isolation”
    

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25. MOCK OBJECTS
    Database connections
    Web services
    File system operations
    

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26. HOW DO WE TEST THIS?
    namespace Grumpy;
    class Acl
    {
    ! protected $_acls;
    ! protected $_request;
    ! protected $_userLevel;
    ! ...
    ! public function __construct($request, $userLevel)!
    ! {
    ! ! ...
    ! !
    ! ! $this->_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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27. HOW DO WE TEST THIS?
    class GrumpyAclTest extends \PHPUnit_Framework_TestCase
    {
    ! public function testAdminPurgeAccessAllowed()
    ! {
    ! ! $mockRequest = $this->getMockBuilder('\Grumpy\Controller\Request')
    ! ! ! ->disableOriginalConstructor()
    ! ! ! ->getMock();
    ! ! $mockController->expects($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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28. HOW DO WE TEST THIS?
    “Protected and
    private methods and
    attributes are difficult
    to test properly”
    

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

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

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

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

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34. METHODS?
    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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35. ATTRIBUTES?
    PHP’S Reflection API
    PHPUnit lets you check attribute
    values but not set them
    

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36. HOW DO YOU TEST THIS?
    “If your unit test
    actually uses the
    database, you are
    doing it wrong”
    

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37. HOW DO YOU TEST THIS?
    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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38. HOW DO YOU TEST THIS?
    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));
    ! ! $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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39. HOW DO YOU TEST THIS?
    “API calls should
    be done via
    wrapper methods”
    

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40. HOW DO YOU TEST THIS?
    class HipsterApi
    {
    ! public function getBands()
    ! {
    ! ! return $this->_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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41. HOW DO WE TEST THIS?
    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);
    ! ! $hipsterApiWrapper = new HipsterApiWrapper($mockHipsterApi);
    ! ! $testData = $hipsterApiWrapper->getBands();
    ! ! !
    ! ! $this->assertEquals(
    ! ! ! $expectedData,
    ! ! ! $testData,
    ! ! ! 'Did not get expected getBands() result from HipsterApi'
    ! ! );
    ! }
    }
    

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42. ENVIRONMENTS
    “Your app shouldn’t
    care what environment
    it runs in.”
    

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43. ENVIRONMENTS
    “Keep config files
    for each environment
    under version control”
    https:/
    /github.com/flogic/
    whiskey_disk
    

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44. WHAT NOT TO DO
    

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45. WHAT NOT TO DO
    “Avoid the use of
    static method calls”
    

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46. WHAT NOT TO DO
    class Presentation
    {
    public function speak()
    {
    $rant = Grumpy::getOpinion();
    }
    }
    

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47. WHAT NOT TO DO
    1. Get a Dependency Injection Container
    2. Create a fake version of your object
    with the static call
    3. use the container inside the test
    

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48. WHAT NOT TO DO
    “Avoid creating
    new non-core objects
    unless it’s a factory”
    

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49. WHAT NOT TO DO
    class Presentation
    {
    public function convert($name)
    {
    $slides = new SlideDriver();
    $slides->toPdf($name);
    }
    }
    

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50. WHAT NOT TO DO
    1. Learn dependency injection
    2. Create version of your object
    3. Inject the dependency
    

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51. WHAT NOT TO DO
    “Be careful with
    chaining methods”
    

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52. WHAT NOT TO DO
    class Presentation
    {
    public function munge($frozbit)
    {
    $widgets = $frozbit
    ->what()
    ->is()
    ->this()
    ->i()
    ->dont()
    ->even();
    }
    }
    

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53. WHAT NOT TO DO
    1. Reduce the number of chains
    2. Reduce the amount of work
    

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54. RESOURCES
    The Grumpy Programmer’s
    Guide to Building
    Testable PHP Applications
    http:/
    /grumpy-testing.com
    

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55. RESOURCES
    The Grumpy Programmer’s
    PHPUnit Cookbook
    http:/
    /grumpy-phpunit.com
    

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56. RESOURCES
    The people
    sitting next
    to you
    

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57. THANK YOU!
    @grmpyprogrammer
    http:/
    /www.littlehart.net/atthekeyboard
    https:/
    /joind.in/8233
    

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