What should you test with your unit tests? Some people will say that unit behaviour is best tested through it's outcomes. But what if communication between units itself is more important than the results of it? This session will introduce you to two different ways of unit-testing and show you a way to assert your object behaviours through their communications.

1. Design how your
objects talk
through mocking

2. ”
– Reverse Focus on the reverse mortgages
“One of the most common mistakes people
make is to fixate on the goal or expected
outcome while ignoring their underlying
behaviours.”

3. @everzet
• BDD Practice Manager
• Software Engineer
• Creator of Behat, Mink,
Prophecy, PhpSpec2
• Contributor to Symfony2,
Doctrine2, Composer

4. This talk is about
• Test-driven development with and without mocks
• Introducing and making sense of different types of
doubles
• OOP as a messaging paradigm
• Software design as a response to messaging
observations
• Code

5. Test-driven
development
By Example
!
“The TDD book”
!
Circa 2002

6. Money multiplication test from the TDD book
public void testMultiplication()
{
Dollar five = new Dollar(5);
Dollar product = five.times(2);
!
assertEquals(10, product.amount);
!
product = five.times(3);
!
assertEquals(15, product.amount);
}

7. Money multiplication test in PHP
public function testMultiplication()
{
$five = new Dollar(5);
$product = $five->times(2);
$this->assertEquals(10, $product->getAmount());
$product = $five->times(3);
$this->assertEquals(15, $product->getAmount());
}

8. Event dispatching test
public function testEventIsDispatchedDuringRegistration()
{
$dispatcher = new EventDispatcher();
$repository = new UserRepository();
$manager = new UserManager($repository, $dispatcher);
!
$timesDispatched = 0;
$dispatcher->addListener(
'userIsRegistered',
function() use($timesDispatched) {
$timesDispatched += 1;
}
);
!
$user = User::signup('ever.zet@gmail.com');
$manager->registerUser($user);
$this->assertSame(1, $timesDispatched);
}

9. Event dispatching test
public function testEventIsDispatchedDuringRegistration()
{
$dispatcher = new EventDispatcher();
$repository = new UserRepository();
$manager = new UserManager($repository, $dispatcher);
!
$timesDispatched = 0;
$dispatcher->addListener(
'userIsRegistered',
function() use($timesDispatched) {
$timesDispatched += 1;
}
);
!
$user = User::signup('ever.zet@gmail.com');
$manager->registerUser($user);
$this->assertSame(1, $timesDispatched);
}

12. ”
– Ralph Waldo Emerson
“Life is a journey, not a destination.”

13. Growing
Object-Oriented
Software,
Guided by Tests
!
“The GOOS book”
!
Circa 2009

14. Event dispatching test
public function testEventIsDispatchedDuringRegistration()
{
$dispatcher = new EventDispatcher();
$repository = new UserRepository();
$manager = new UserManager($repository, $dispatcher);
!
$timesDispatched = 0;
$dispatcher->addListener(
'userIsRegistered',
function() use($timesDispatched) {
$timesDispatched += 1;
}
);
!
$user = User::signup('ever.zet@gmail.com');
$manager->registerUser($user);
$this->assertSame(1, $timesDispatched);
}

15. Event dispatching collaborators
public function testEventIsDispatchedDuringRegistration()
{
$dispatcher = new EventDispatcher();
$repository = new UserRepository();
$manager = new UserManager($repository, $dispatcher);
!
$timesDispatched = 0;
$dispatcher->addListener(
'userIsRegistered',
function() use($timesDispatched) {
$timesDispatched += 1;
}
);
!
$user = User::signup('ever.zet@gmail.com');
$manager->registerUser($user);
$this->assertSame(1, $timesDispatched);
}

16. Find the message
public function testEventIsDispatchedDuringRegistration()
{
$dispatcher = new EventDispatcher();
$repository = new UserRepository();
$manager = new UserManager($repository, $dispatcher);
!
$timesDispatched = 0;
$dispatcher->addListener(
'userIsRegistered',
function() use($timesDispatched) {
$timesDispatched += 1;
}
);
!
$user = User::signup('ever.zet@gmail.com');
$manager->registerUser($user);
$this->assertSame(1, $timesDispatched);
}

17. messages or state

18. ”
– Alan Kay, father of OOP
“OOP to me means only messaging, local
retention and protection and hiding of state-
process, and extreme late-binding of all things.”

19. Interfaces
interface LoginMessenger {
public function askForCard();
public function askForPin();
}
interface InputMessenger {
public function askForAccount();
public function askForAmount();
}
interface WithdrawalMessenger {
public function tellNoMoney();
public function tellMachineEmpty();
}

20. Doubles
1. Dummy
2. Stub
3. Spy
4. Mock
5. Fake

21. Prophecy
(1) use ProphecyProphet;
(2) use ProphecyArgument;
(3) $prophet = new Prophet();
(4) $userProphecy = $prophet->prophesize(UserInterface::class);
(5) $userProphecy->changeName('everzet')->shouldBeCalled();
(6) $user = $userProphecy->reveal();
(7) $user->changeName('_md');
(8) $prophet->checkPredictions();

22. 1. Dummy

23. 1. Dummy
class System {
private $authorizer;
public function __construct(Authorizer $authorizer) {
$this->authorizer = $authorizer;
}
public function getLoginCount() {
return 0;
}
}

24. 1. Dummy
class System {
private $authorizer;
public function __construct(Authorizer $authorizer) {
$this->authorizer = $authorizer;
}
public function getLoginCount() {
return 0;
}
}
!
public function testNewlyCreatedSystemHasNoLoggedInUsers() {
$auth = $this->prophesize(Authorizer::class);
$system = new System($auth->reveal());
$this->assertSame(0, $system->getLoginCount());
}

25. 1. Dummy
class System {
private $authorizer;
public function __construct(Authorizer $authorizer) {
$this->authorizer = $authorizer;
}
public function getLoginCount() {
return 0;
}
}
!
public function testNewlyCreatedSystemHasNoLoggedInUsers() {
$auth = $this->prophesize(Authorizer::class);
$system = new System($auth->reveal());
$this->assertSame(0, $system->getLoginCount());
}

26. 2. Stub

27. 2. Stub
class System {
// ...
!
public function logIn($username, $password) {
if ($this->authorizer->authorize($username, $password)) {
$this->loginCount++;
}
}
!
public function getLoginCount() {
return $this->loginCount;
}
}

28. 2. Stub
class System {
// ...
!
public function logIn($username, $password) {
if ($this->authorizer->authorize($username, $password)) {
$this->loginCount++;
}
}
!
public function getLoginCount() {
return $this->loginCount;
}
}
!
public function testCountsSuccessfullyAuthorizedLogIns() {
$auth = $this->prophesize(Authorizer::class);
$system = new System($auth->reveal());
!
$auth->authorize('everzet', '123')->willReturn(true);
!
$system->logIn('everzet', ‘123’);
!
$this->assertSame(1, $system->getLoginCount());
}

29. 2. Stub
class System {
// ...
!
public function logIn($username, $password) {
if ($this->authorizer->authorize($username, $password)) {
$this->loginCount++;
}
}
!
public function getLoginCount() {
return $this->loginCount;
}
}
!
public function testCountsSuccessfullyAuthorizedLogIns() {
$auth = $this->prophesize(Authorizer::class);
$system = new System($auth->reveal());
!
$auth->authorize('everzet', '123')->willReturn(true);
!
$system->logIn('everzet', ‘123’);
!
$this->assertSame(1, $system->getLoginCount());
}

30. 2. Stub
class System {
// ...
!
public function logIn($username, $password) {
if ($this->authorizer->authorize($username, $password)) {
$this->loginCount++;
}
}
!
public function getLoginCount() {
return $this->loginCount;
}
}
!
public function testCountsSuccessfullyAuthorizedLogIns() {
$auth = $this->prophesize(Authorizer::class);
$system = new System($auth->reveal());
!
$auth->authorize('everzet', '123')->willReturn(true);
!
$system->logIn(‘_md', ‘321’);
!
$this->assertSame(1, $system->getLoginCount());
}

31. 3. Spy

32. 3. Spy
class System {
// ...
!
public function logIn($username, $password) {
if ($this->authorizer->authorize($username, $password)) {
$this->loginCount++;
$this->lastLoginTimer->recordLogin($username);
}
}
}

33. 3. Spy
class System {
// ...
!
public function logIn($username, $password) {
if ($this->authorizer->authorize($username, $password)) {
$this->loginCount++;
$this->lastLoginTimer->recordLogin($username);
}
}
}
!
public function testCountsSuccessfullyAuthorizedLogIns() {
$auth = $this->prophesize(Authorizer::class);
$timer = $this->prophesize(LoginTimer::class);
$system = new System($auth->reveal(), $timer->reveal());
$auth->authorize('everzet', '123')->willReturn(true);
!
$system->login('everzet', '123');
!
$timer->recordLogin('everzet')->shouldHaveBeenCalled();
}

34. 3. Spy
class System {
// ...
!
public function logIn($username, $password) {
if ($this->authorizer->authorize($username, $password)) {
$this->loginCount++;
$this->lastLoginTimer->recordLogin($username);
}
}
}
!
public function testCountsSuccessfullyAuthorizedLogIns() {
$auth = $this->prophesize(Authorizer::class);
$timer = $this->prophesize(LoginTimer::class);
$system = new System($auth->reveal(), $timer->reveal());
$auth->authorize('everzet', '123')->willReturn(true);
!
$system->login('everzet', '123');
!
$timer->recordLogin('everzet')->shouldHaveBeenCalled();
}

35. 4. Mock

36. 3. Spy
class System {
// ...
!
public function logIn($username, $password) {
if ($this->authorizer->authorize($username, $password)) {
$this->loginCount++;
$this->lastLoginTimer->recordLogin($username);
}
}
}
!
public function testCountsSuccessfullyAuthorizedLogIns() {
$auth = $this->prophesize(Authorizer::class);
$timer = $this->prophesize(LoginTimer::class);
$system = new System($auth->reveal(), $timer->reveal());
$auth->authorize('everzet', '123')->willReturn(true);
!
$system->login('everzet', '123');
!
$timer->recordLogin('everzet')->shouldHaveBeenCalled();
}

37. 4. Mock
class System {
// ...
!
public function logIn($username, $password) {
if ($this->authorizer->authorize($username, $password)) {
$this->loginCount++;
$this->lastLoginTimer->recordLogin($username);
}
}
}
!
public function testCountsSuccessfullyAuthorizedLogIns() {
$auth = $this->prophesize(Authorizer::class);
$timer = $this->prophesize(LoginTimer::class);
$system = new System($auth->reveal(), $timer->reveal());
$auth->authorize('everzet', '123')->willReturn(true);
!
$timer->recordLogin('everzet')->shouldBeCalled();
!
$system->login('everzet', '123');
!
$this->getProphet()->checkPredictions();
}

38. Back to the
event dispatcher

39. Find the message
public function testEventIsDispatchedDuringRegistration()
{
$dispatcher = new EventDispatcher();
$repository = new UserRepository();
$manager = new UserManager($repository, $dispatcher);
!
$timesDispatched = 0;
$dispatcher->addListener(
'userIsRegistered',
function() use($timesDispatched) {
$timesDispatched += 1;
}
);
!
$user = User::signup('ever.zet@gmail.com');
$manager->registerUser($user);
$this->assertSame(1, $timesDispatched);
}

40. Communication over state
public function testEventIsDispatchedDuringRegistration()
{
$repository = $this->prophesize(UserRepository::class);
$dispatcher = $this->prophesize(EventDispatcher::class);
$manager = new UserManager(
$repository->reveal(),
$dispatcher->reveal()
);
$user = User::signup('ever.zet@gmail.com');
$manager->registerUser($user);
!
$dispatcher->dispatch('userIsRegistered', Argument::any())
->shouldHaveBeenCalled();
}

41. Exposed communication
public function testEventIsDispatchedDuringRegistration()
{
$repository = $this->prophesize(UserRepository::class);
$dispatcher = $this->prophesize(EventDispatcher::class);
$manager = new UserManager(
$repository->reveal(),
$dispatcher->reveal()
);
$user = User::signup('ever.zet@gmail.com');
$manager->registerUser($user);
!
$dispatcher->dispatch('userIsRegistered', Argument::any())
->shouldHaveBeenCalled();
}

42. Design?

43. ”
– The Observer Effect
“The act of observing will influence the
phenomenon being observed.”

44. The 1st case:
simple controller

45. Simple Symfony2 controller
public function packagesListAction(Request $req, User $user) {
$packages = $this->getDoctrine()
->getRepository('WebBundle:Package')
->getFilteredQueryBuilder(array('maintainer' => $user->getId()))
->orderBy('p.name')
->getQuery()
->execute();
!
return $this->render('WebBundle:User:packages.html.twig', [
'packages' => $packages
]);
}

46. “Simple” Symfony2 controller test
public function testShowMaintainedPackages() {
$request = new Request();
$user = new User('everzet');
$container = $this->prophesize(ContainerInterface::class);
$doctrine = $this->prophesize(EntityManager::class);
$repository = $this->prophesize(PackageRepository::class);
$queryBuilder = $this->prophesize(QueryBuilder::class);
$query = $this->prophesize(Query::class);
$packages = [new Package('Behat'), new Package('PhpSpec')];
$templating = $this->prophesize(EngineInterface::class);
$response = new Response('User packages');
!
$container->get('doctrine.orm')->willReturn($doctrine);
$doctrine->getRepository('WebBundle:Package')->willReturn($repository);
$repository->getFilteredQueryBuilder(['maintainer' => $user->getId()])
->willReturn($queryBuilder);
$queryBuilder->orderBy('p.name')->shouldBeCalled();
$queryBuilder->getQuery()->willReturn($query);
$query->execute()->willReturn($packages);
$templating->renderResponse(
'WebBundle:User:packages.html.twig', ['packages' => $packages], null)
->willReturn($response);
!
$controller = new UserController();
$controller->setContainer($container);
$controllerResult = $controller->maintainsPackagesAction($request, $user);
!
$this->assertEquals($response, $controllerResult);
}

47. “Simple” Symfony2 controller test
public function testShowMaintainedPackages() {
$request = new Request();
$user = new User('everzet');
$container = $this->prophesize(ContainerInterface::class);
$doctrine = $this->prophesize(EntityManager::class);
$repository = $this->prophesize(PackageRepository::class);
$queryBuilder = $this->prophesize(QueryBuilder::class);
$query = $this->prophesize(Query::class);
$packages = [new Package('Behat'), new Package('PhpSpec')];
$templating = $this->prophesize(EngineInterface::class);
$response = new Response('User packages');
!
$container->get('doctrine.orm')->willReturn($doctrine);
$doctrine->getRepository('WebBundle:Package')->willReturn($repository);
$repository->getFilteredQueryBuilder(['maintainer' => $user->getId()])
->willReturn($queryBuilder);
$queryBuilder->orderBy('p.name')->shouldBeCalled();
$queryBuilder->getQuery()->willReturn($query);
$query->execute()->willReturn($packages);
$templating->renderResponse(
'WebBundle:User:packages.html.twig', ['packages' => $packages], null)
->willReturn($response);
!
$controller = new UserController();
$controller->setContainer($container);
$controllerResult = $controller->maintainsPackagesAction($request, $user);
!
$this->assertEquals($response, $controllerResult);
}

48. “Simple” Symfony2 controller test
public function testShowMaintainedPackages() {
$request = new Request();
$user = new User('everzet');
$container = $this->prophesize(ContainerInterface::class);
$doctrine = $this->prophesize(EntityManager::class);
$repository = $this->prophesize(PackageRepository::class);
$queryBuilder = $this->prophesize(QueryBuilder::class);
$query = $this->prophesize(Query::class);
$packages = [new Package('Behat'), new Package('PhpSpec')];
$templating = $this->prophesize(EngineInterface::class);
$response = new Response('User packages');
!
$container->get('doctrine.orm')->willReturn($doctrine);
$doctrine->getRepository('WebBundle:Package')->willReturn($repository);
$repository->getFilteredQueryBuilder(['maintainer' => $user->getId()])
->willReturn($queryBuilder);
$queryBuilder->orderBy('p.name')->shouldBeCalled();
$queryBuilder->getQuery()->willReturn($query);
$query->execute()->willReturn($packages);
$templating->renderResponse(
'WebBundle:User:packages.html.twig', ['packages' => $packages], null)
->willReturn($response);
!
$controller = new UserController();
$controller->setContainer($container);
$controllerResult = $controller->maintainsPackagesAction($request, $user);
!
$this->assertEquals($response, $controllerResult);
}

49. Single
Responsibility
Principle

50. Simpler Symfony2 controller simple test
public function testShowMaintainedPackages() {
$user = new User('everzet');
$repository = $this->prophesize(PackageRepository::class);
$templating = $this->prophesize(EngineInterface::class);
$packages = [new Package('Behat'), new Package('PhpSpec')];
$response = new Response('User packages');
!
$repository->getMaintainedPackagesOrderedByName($user)->willReturn($packages);
$templating->renderResponse(
'WebBundle:User:packages.html.twig', ['packages' => $packages], null)
->willReturn($response);
!
$controller = new UserController($repository->reveal(), $templating->reveal());
$controllerResult = $controller->maintainsPackagesAction($user);
!
$this->assertEquals($response, $controllerResult);
}

51. Simpler Symfony2 controller simple test
public function testShowMaintainedPackages() {
$user = new User('everzet');
$repository = $this->prophesize(PackageRepository::class);
$templating = $this->prophesize(EngineInterface::class);
$packages = [new Package('Behat'), new Package('PhpSpec')];
$response = new Response('User packages');
!
$repository->getMaintainedPackagesOrderedByName($user)->willReturn($packages);
$templating->renderResponse(
'WebBundle:User:packages.html.twig', ['packages' => $packages], null)
->willReturn($response);
!
$controller = new UserController($repository->reveal(), $templating->reveal());
$controllerResult = $controller->maintainsPackagesAction($user);
!
$this->assertEquals($response, $controllerResult);
}

52. Simpler Symfony2 controller
public function maintainsPackagesAction(User $user) {
$packages = $this->repo->getMaintainedPackagesOrderedByName($user);
!
return $this->tpl->renderResponse('WebBundle:User:packages.html.twig', [
'packages' => $packages
]);
}

53. The 2nd case:
basket checkout

54. Basket checkout
class Basket {
// ...
!
public function checkout(OrderProcessor $processor) {
$totalPrice = new Price::free();
foreach ($this->getItems() as $item) {
$totalPrice = $totalPrice->add($item->getPrice());
$processor->addItem($item);
}
!
$payment = new CashPayment::fromPrice($totalPrice);
$processor->setPayment($payment);
$processor->pay();
}
}

55. Basket checkout test
public function testCheckout() {
$items = [new Item(Price::fromInt(10), Price::fromInt(5)];
$processor = $this->prophesize(OrderProcessor::class);
$basket = new Basket($items);
$basket->checkout($processor->reveal());
$processor->addItem($items[0])->shouldHaveBeenCalled();
$processor->addItem($items[1])->shouldHaveBeenCalled();
$processor->setPayment(Argument::which('getPrice', 15))->shouldHaveBeenCalled();
$processor->pay()->shouldHaveBeenCalled();
}

56. Basket checkout test two payments
public function testCheckoutWithCash() {
$items = [new Item(Price::fromInt(10), Price::fromInt(5)];
$processor = $this->prophesize(OrderProcessor::class);
$basket = new Basket($items, $credit = false);
$basket->checkout($processor->reveal());
$processor->addItem($items[0])->shouldHaveBeenCalled();
$processor->addItem($items[1])->shouldHaveBeenCalled();
$processor->setPayment(Argument::allOf(
Argument::type(CashPayment::class), Argument::which('getPrice', 15)
))->shouldHaveBeenCalled();
$processor->pay()->shouldHaveBeenCalled();
}
public function testCheckoutWithCreditCard() {
$items = [new Item(Price::fromInt(10), Price::fromInt(5)];
$processor = $this->prophesize(OrderProcessor::class);
$basket = new Basket($items, $credit = true);
$basket->checkout($processor->reveal());
$processor->addItem($items[0])->shouldHaveBeenCalled();
$processor->addItem($items[1])->shouldHaveBeenCalled();
$processor->setPayment(Argument::allOf(
Argument::type(CreditPayment::class), Argument::which('getPrice', 15)
))->shouldHaveBeenCalled();
$processor->pay()->shouldHaveBeenCalled();
}

57. Basket checkout test two payments
public function testCheckoutWithCash() {
$items = [new Item(Price::fromInt(10), Price::fromInt(5)];
$processor = $this->prophesize(OrderProcessor::class);
$basket = new Basket($items, $credit = false);
$basket->checkout($processor->reveal());
$processor->addItem($items[0])->shouldHaveBeenCalled();
$processor->addItem($items[1])->shouldHaveBeenCalled();
$processor->setPayment(Argument::allOf(
Argument::type(CashPayment::class), Argument::which('getPrice', 15)
))->shouldHaveBeenCalled();
$processor->pay()->shouldHaveBeenCalled();
}
public function testCheckoutWithCreditCard() {
$items = [new Item(Price::fromInt(10), Price::fromInt(5)];
$processor = $this->prophesize(OrderProcessor::class);
$basket = new Basket($items, $credit = true);
$basket->checkout($processor->reveal());
$processor->addItem($items[0])->shouldHaveBeenCalled();
$processor->addItem($items[1])->shouldHaveBeenCalled();
$processor->setPayment(Argument::allOf(
Argument::type(CreditPayment::class), Argument::which('getPrice', 15)
))->shouldHaveBeenCalled();
$processor->pay()->shouldHaveBeenCalled();
}

58. Basket checkout duplication in test
public function testCheckoutWithCash() {
$items = [new Item(Price::fromInt(10), Price::fromInt(5)];
$processor = $this->prophesize(OrderProcessor::class);
$basket = new Basket($items, $credit = false);
$basket->checkout($processor->reveal());
$processor->addItem($items[0])->shouldHaveBeenCalled();
$processor->addItem($items[1])->shouldHaveBeenCalled();
$processor->setPayment(Argument::allOf(
Argument::type(CashPayment::class), Argument::which('getPrice', 15)
))->shouldHaveBeenCalled();
$processor->pay()->shouldHaveBeenCalled();
}
public function testCheckoutWithCreditCard() {
$items = [new Item(Price::fromInt(10), Price::fromInt(5)];
$processor = $this->prophesize(OrderProcessor::class);
$basket = new Basket($items, $credit = true);
$basket->checkout($processor->reveal());
$processor->addItem($items[0])->shouldHaveBeenCalled();
$processor->addItem($items[1])->shouldHaveBeenCalled();
$processor->setPayment(Argument::allOf(
Argument::type(CreditPayment::class), Argument::which('getPrice', 15)
))->shouldHaveBeenCalled();
$processor->pay()->shouldHaveBeenCalled();
}

59. Open
Closed
Principle

60. Basket checkout test simplification
public function testCheckoutWithPaymentMethod() {
$items = [new Item(Price::fromInt(10), Price::fromInt(5)];
$processor = $this->prophesize(OrderProcessor::class);
$paymentMethod = $this->prophesize(PaymentMethod::class);
$payment = $this->prophesize(Payment::class);
$paymentMethod->acceptPayment(Price::fromInt(15))->willReturn($payment);
$basket = new Basket($items);
$basket->checkout($processor->reveal(), $paymentMethod->reveal());
$processor->addItem($items[0])->shouldHaveBeenCalled();
$processor->addItem($items[1])->shouldHaveBeenCalled();
$processor->setPayment($payment)->shouldHaveBeenCalled();
$processor->pay()->shouldHaveBeenCalled();
}

61. Basket checkout test simplification
public function testCheckoutWithPaymentMethod() {
$items = [new Item(Price::fromInt(10), Price::fromInt(5)];
$processor = $this->prophesize(OrderProcessor::class);
$paymentMethod = $this->prophesize(PaymentMethod::class);
$payment = $this->prophesize(Payment::class);
$paymentMethod->acceptPayment(Price::fromInt(15))->willReturn($payment);
$basket = new Basket($items);
$basket->checkout($processor->reveal(), $paymentMethod->reveal());
$processor->addItem($items[0])->shouldHaveBeenCalled();
$processor->addItem($items[1])->shouldHaveBeenCalled();
$processor->setPayment($payment)->shouldHaveBeenCalled();
$processor->pay()->shouldHaveBeenCalled();
}

62. Final basket checkout
class Basket {
// ...
public function checkout(OrderProcessor $processor, PaymentMethod $method) {
$totalPrice = new Price::free();
foreach ($this->getItems() as $item) {
$totalPrice = $totalPrice->add($item->getPrice());
$processor->addItem($item);
}
$payment = $method->acceptPayment($totalPrice);
$processor->setPayment($payment);
$processor->pay();
}
}

63. Final basket checkout
class Basket {
// ...
public function checkout(OrderProcessor $processor, PaymentMethod $method) {
$totalPrice = new Price::free();
foreach ($this->getItems() as $item) {
$totalPrice = $totalPrice->add($item->getPrice());
$processor->addItem($item);
}
$payment = $method->acceptPayment($totalPrice);
$processor->setPayment($payment);
$processor->pay();
}
}

64. The 3rd case:
browser emulation

65. Browser
class Browser {
public function __construct(BrowserDriver $driver) {
$this->driver = $driver;
}
public function goto($url) {
$this->driver->boot();
$this->driver->visit($url);
}
}

66. Browser drivers
interface BrowserDriver {
public function boot();
public function visit($url);
}
!
interface HeadlessBrowserDriver extends BrowserDriver {}
!
class SeleniumDriver implements BrowserDriver {
public function boot() {
$this->selenium->startBrowser($this->browser);
}
!
public function visit($url) {
$this->selenium->visitUrl($url);
}
}
!
class GuzzleDriver implements HeadlessBrowserDriver {
public function boot() {}
!
public function visit($url) {
$this->guzzle->openUrl($url);
}
}

67. Headless driver test
public function testVisitingProvidedUrl() {
$url = 'http://en.wikipedia.org';
$driver = $this->prophesize(HeadlessBrowserDriver::class);
!
$driver->visit($url)->shouldBeCalled();
!
$browser = new Browser($driver->reveal());
$browser->goto($url);
!
$this->getProphecy()->checkPredictions();
}

68. Failing headless driver test
public function testVisitingProvidedUrl() {
$url = 'http://en.wikipedia.org';
$driver = $this->prophesize(HeadlessBrowserDriver::class);
!
$driver->visit($url)->shouldBeCalled();
!
$browser = new Browser($driver->reveal());
$browser->goto($url);
!
$this->getProphecy()->checkPredictions();
}

69. Refused Bequest

70. Headless driver implementation
class GuzzleDriver implements HeadlessBrowserDriver {
!
public function boot() {}
!
public function visit($url) {
$this->guzzle->openUrl($url);
}
}

71. Headless driver simple behaviour
class GuzzleDriver implements HeadlessBrowserDriver {
!
public function boot() {}
!
public function visit($url) {
$this->guzzle->openUrl($url);
}
}

72. Headless driver that knows about booting
class GuzzleDriver implements HeadlessBrowserDriver {
!
public function boot() {
$this->allowDoActions = true;
}
public function visit($url) {
if ($this->allowDoActions)
$this->guzzle->openUrl($url);
}
}

73. Liskov
Substitution
Principle

74. Adapter layer between BrowserDriver and HeadlessBrowserDriver
interface HeadlessBrowserDriver {
public function visit($url);
}
!
class GuzzleDriver implements HeadlessBrowserDriver {
public function visit($url) {
$this->guzzle->openUrl($url);
}
}
!
final class HeadlessBrowserAdapter implements BrowserDriver {
private $headlessDriver, $allowDoAction = false;
!
public function __construct(HeadlessBrowserDriver $headlessDriver) {
$this->headlessDriver = $headlessDriver;
}
!
public function boot() {
$this->allowDoActions = true;
}
!
public function visit($url) {
if ($this->allowDoActions)
$this->headlessDriver->visit($url);
}
}

75. Dirty adapter layer between BrowserDriver and HeadlessBrowserDriver
interface HeadlessBrowserDriver {
public function visit($url);
}
!
class GuzzleDriver implements HeadlessBrowserDriver {
public function visit($url) {
$this->guzzle->openUrl($url);
}
}
!
final class HeadlessBrowserAdapter implements BrowserDriver {
private $headlessDriver, $allowDoAction = false;
!
public function __construct(HeadlessBrowserDriver $headlessDriver) {
$this->headlessDriver = $headlessDriver;
}
!
public function boot() {
$this->allowDoActions = true;
}
!
public function visit($url) {
if ($this->allowDoActions)
$this->headlessDriver->visit($url);
}
}

76. Single adapter layer between BrowserDriver and HeadlessBrowserDriver
interface HeadlessBrowserDriver {
public function visit($url);
}
!
class GuzzleDriver implements HeadlessBrowserDriver {
public function visit($url) {
$this->guzzle->openUrl($url);
}
}
!
final class HeadlessBrowserAdapter implements BrowserDriver {
private $headlessDriver, $allowDoAction = false;
!
public function __construct(HeadlessBrowserDriver $headlessDriver) {
$this->headlessDriver = $headlessDriver;
}
!
public function boot() {
$this->allowDoActions = true;
}
!
public function visit($url) {
if ($this->allowDoActions)
$this->headlessDriver->visit($url);
}
}

77. The 4th case:
ATM screen

78. ATM messenger interface
interface Messenger {
public function askForCard();
public function askForPin();
public function askForAccount();
public function askForAmount();
public function tellNoMoney();
public function tellMachineEmpty();
}

79. City ATM login test
public function testAtmAsksForCardAndPinDuringLogin() {
$messenger = $this->prophesize(Messenger::class);
!
$messenger->askForCard()->shouldBeCalled();
$messenger->askForPin()->shouldBeCalled();
!
$atm = new CityAtm($messenger->reveal());
$atm->login();
!
$this->getProphet()->checkPredictions();
}

80. City ATM login test
public function testAtmAsksForCardAndPinDuringLogin() {
$messenger = $this->prophesize(Messenger::class);
!
$messenger->askForCard()->shouldBeCalled();
$messenger->askForPin()->shouldBeCalled();
!
$atm = new CityAtm($messenger->reveal());
$atm->login();
!
$this->getProphet()->checkPredictions();
}

81. Interface
Segregation
Principle

82. City ATM login test
public function testAtmAsksForCardAndPinDuringLogin() {
$messenger = $this->prophesize(LoginMessenger::class);
!
$messenger->askForCard()->shouldBeCalled();
$messenger->askForPin()->shouldBeCalled();
!
$atm = new CityAtm($messenger->reveal());
$atm->login();
!
$this->getProphet()->checkPredictions();
}

83. ATM messenger interface(s)
interface LoginMessenger {
public function askForCard();
public function askForPin();
}
!
interface InputMessenger {
public function askForAccount();
public function askForAmount();
}
!
interface WithdrawalMessenger {
public function tellNoMoney();
public function tellMachineEmpty();
}
!
interface Messenger extends LoginMessenger,
InputMessenger,
WithdrawalMessenger

84. The 5th case:
entity repository

85. Doctrine entity repository
class JobRepository extends EntityRepository {
public function findJobByName($name) {
return $this->findOneBy(['name' => $name]);
}
}

86. Doctrine entity repository test
public function testFindingJobsByName() {
$em = $this->prophesize('EntityManager');
$cmd = $this->prophesize('ClassMetadata');
$uow = $this->prophesize('UnitOfWork');
$ep = $this->prophesize('EntityPersister');
$job = Job::fromName('engineer');
!
$em->getUnitOfWork()->willReturn($uow);
$uow->getEntityPersister(Argument::any())->willReturn($ep);
$ep->load(['name' => 'engineer'], null, null, [], null, 1, null)
->willReturn($job);
!
$repo = new JobRepository($em->reveal(), $cmd->reveal());
$actualJob = $repo->findJobByName('engineer');
!
$this->assertSame($job, $actualJob);
}

87. Doctrine entity repository test
public function testFindingJobsByName() {
$em = $this->prophesize('EntityManager');
$cmd = $this->prophesize('ClassMetadata');
$uow = $this->prophesize('UnitOfWork');
$ep = $this->prophesize('EntityPersister');
$job = Job::fromName('engineer');
!
$em->getUnitOfWork()->willReturn($uow);
$uow->getEntityPersister(Argument::any())->willReturn($ep);
$ep->load(['name' => 'engineer'], null, null, [], null, 1, null)
->willReturn($job);
!
$repo = new JobRepository($em->reveal(), $cmd->reveal());
$actualJob = $repo->findJobByName('engineer');
!
$this->assertSame($job, $actualJob);
}

88. Do not mock things
you do not own

89. Doctrine entity repository test
public function testFindingJobsByName() {
$em = $this->prophesize('EntityManager');
$cmd = $this->prophesize('ClassMetadata');
$uow = $this->prophesize('UnitOfWork');
$ep = $this->prophesize('EntityPersister');
$job = Job::fromName('engineer');
!
$em->getUnitOfWork()->willReturn($uow);
$uow->getEntityPersister(Argument::any())->willReturn($ep);
$ep->load(['name' => 'engineer'], null, null, [], null, 1, null)
->willReturn($job);
!
$repo = new JobRepository($em->reveal(), $cmd->reveal());
$actualJob = $repo->findJobByName('engineer');
!
$this->assertSame($job, $actualJob);
}

90. Dependency
Inversion
Principle

91. Job repository & Doctrine implementation of it
interface
JobRepository
{
public
function
findJobByName($name);
}
!
class
DoctrineJobRepository
extends
EntityRepository
implements
JobRepository
{
!
public
function
findJobByName($name)
{
return
$this-­‐>findOneBy(['name'
=>
$name]);
}
}

92. Job repository & Doctrine implementation of it
interface
JobRepository
{
public
function
findJobByName($name);
}
!
class
DoctrineJobRepository
extends
EntityRepository
implements
JobRepository
{
!
public
function
findJobByName($name)
{
return
$this-­‐>findOneBy(['name'
=>
$name]);
}
}

93. Job repository & Doctrine implementation of it
interface
JobRepository
{
public
function
findJobByName($name);
}
!
class
DoctrineJobRepository
extends
EntityRepository
implements
JobRepository
{
!
public
function
findJobByName($name)
{
return
$this-­‐>findOneBy(['name'
=>
$name]);
}
}

94. Recap:

95. Recap:
1. State-focused TDD is not the only way to TDD

96. Recap:
1. State-focused TDD is not the only way to TDD
2. Messaging is far more important concept of OOP than
the state

97. Recap:
1. State-focused TDD is not the only way to TDD
2. Messaging is far more important concept of OOP than
the state
3. By focusing on messaging, you expose messaging
problems

98. Recap:
1. State-focused TDD is not the only way to TDD
2. Messaging is far more important concept of OOP than
the state
3. By focusing on messaging, you expose messaging
problems
4. By exposing messaging problems, you could discover
most of the SOLID principles violation before they
happen

99. Recap:
1. State-focused TDD is not the only way to TDD
2. Messaging is far more important concept of OOP than the
state
3. By focusing on messaging, you expose messaging
problems
4. By exposing messaging problems, you could discover
most of the SOLID principles violation before they happen
5. Prophecy is awesome

100. 6. Messages define
objects behaviour

103. Thank you!