Testing Strategies for Legacy PHP Applications exploring how to test the untestable Jeff Carouth Wednesday, August 15, 12 

Howdy! My name is Jeff I tweet as @jcarouth I blog at http://carouth.com I develop software at I test code because I’m not perfect Wednesday, August 15, 12 

Legacy Code IS difficult to change often unstructured and likely incomprehensible “Test resistant” Wednesday, August 15, 12 

Legacy Code Dilemma You should have tests in place before making changes. You must make changes to begin writing tests. Wednesday, August 15, 12 

Where Do I Start? Wednesday, August 15, 12 

Wednesday, August 15, 12 

RESIST the urge to Rewrite Wednesday, August 15, 12 

Legacy Code Change Algorithm 1. Identify change points. 2. Find test points. 3. Break dependencies. 4. Write tests. 5. Make changes and refactor. Source: Working Effectively with Legacy Code by Michael Feathers Wednesday, August 15, 12 

RESIST the urge to Rewrite REFACTOR only what is necessary for tests Wednesday, August 15, 12 

In order to refactor As a developer dealing with legacy code I need a mechanism for feedback So that I can make changes fearlessly Wednesday, August 15, 12 

In order to refactor As a developer dealing with legacy code I need a mechanism for feedback So that I can make changes fearlessly acceptance tests Wednesday, August 15, 12 

Legacy Code Test Introduction Algorithm 1. Identify what you need to change. 2. Write pinning test for impacted behavior. 3. Locate test point for unit test. 4. Break dependencies. 5. Write tests. 6. Make changes and refactor. 7. Repeat 5 and 6 until change is completed. Wednesday, August 15, 12 

Cannot Filter Orders By Purchaser Q: What do we need to change? A: The OrderRepository does not correctly filter by purchaser. Wednesday, August 15, 12 

Feature: Orders reporting In order to see how our product inventory moves As a store manager I need to be able to access order records by certain criteria Scenario: Filter orders by purchaser email Given There are 5 orders placed by '[email protected]' And There are 15 orders placed in the past 5 days When I request '/orders/by/purchaser/value/[email protected]' Then I should see 5 total orders Wednesday, August 15, 12 

class OrderRepository { public function __construct() { $this->db = new DbConnection(); } } Wednesday, August 15, 12 

class OrderRepository { public function __construct($db = null) { if (null === $db) { $db = new DbConnection(); } $this->db = $db; } } Wednesday, August 15, 12 

class OrderRepository { public function filterByPurchaserEmail($email) { $purchaserRepository = new CustomerRepository($this->db); $purchaserRepository->findByEmail($email); if (count($purchasers) == 0) { return array(); } $orders = array(); foreach ($purchasers as $purchaser) { $orders = $this->db->findByCustomerId($purchaser['id']); } return $orders; } } Wednesday, August 15, 12 

class OrderRepository { public function filterByPurchaserEmail( $email, $purchaserRepository = null ) { if (null === $purchaserRepository) { $purchaserRepository = new CustomerRepository($this->db); } $purchaserRepository->filterByEmail($email); // ...snip... } } Wednesday, August 15, 12 

class OrderRepositoryTest { public function testFilterByPurchaserShouldReturnOrders() { $dbMock = $this->getMock( 'DbConnection', array('findOrderByCustomerId') ); $customerRepositoryMock = $this->getMock( 'CustomerRepository', array('filterByEmail') ); // ...snip... } } Wednesday, August 15, 12 

class OrderRepositoryTest { public function testFilterByPurchaserShouldReturnOrders() { // ...snip... $dbMock->expects($this->atLeastOnce()) ->method('findOrderByCustomerId') ->with($this->LogicalOr( $this->equalTo($customerIds[0]), $this->equalTo($customerIds[1]) )) ->will($this->returnCallback( function ($customerId) use($testOrders) { return $testOrders[$customerId]; } )); // ...snip... } } Wednesday, August 15, 12 

class OrderRepositoryTest { public function testFilterByPurchaserShouldReturnOrders() { // ...snip... $orderRepository = new OrderRepository($dbMock); $orders = $orderRepository->filterByPurchaserEmail( '[email protected]', $customerRepositoryMock ); $this->assertEquals(7, count($orders)); } } Wednesday, August 15, 12 

class OrderRepository { public function filterByPurchaserEmail($email) { $purchaserRepository = new CustomerRepository($this->db); $purchaserRepository->findByEmail($email); if (count($purchasers) == 0) { return array(); } $orders = array(); foreach ($purchasers as $purchaser) { $orders = $this->db->findByCustomerId($purchaser['id']); } return $orders; } } Wednesday, August 15, 12 

class OrderRepository { public function filterByPurchaserEmail($email) { $purchaserRepository = new CustomerRepository($this->db); $purchaserRepository->findByEmail($email); if (count($purchasers) == 0) { return array(); } $orders = array(); foreach ($purchasers as $purchaser) { $neworders = $this->db->findByCustomerId($purchaser['id']); $orders = $orders + $neworders; } return $orders; } } Wednesday, August 15, 12 

Freedom to Refactor FEARLESSLY Wednesday, August 15, 12 

Thank You! Questions? do you have or Comments? @jcarouth | [email protected] Wednesday, August 15, 12 

Wednesday, August 15, 12 

Resources Acceptance Testing Behat – http://behat.org Mink – http://mink.behat.org Selenium – http://seleniumhq.org/ Reading Wednesday, August 15, 12