@jcarouth / #zendcon also known as testing from the pit of despair Introducing Tests in Legacy PHP Applications 

JEFF CAROUTH DEVELOPER AT LIFTOPIA @jcarouth [email protected] Freenode: #phpmentoring 

What He Said 

Legacy 1. 

Legacy Code IS difficult to change often unstructured and likely incomprehensible “Test resistant” 

Should Vs. Must dilemma 

RESIST the urge to Rewrite 

REFACTOR only what is necessary for tests 

Algorithms 2. 

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 

Break Dependencies Without Tests In Place? Migraine. 

Mechanism For Feedback 

Acceptance Tests masquerade as pinning tests 

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//features/registereduser.feature Feature: Registered users can run fizzbuzz As a registered fizzbuzzer I want to be able to run fizzbuzz Background: Given An account exists for user "behat" password "letmein" When I am on homepage And I log in as "behat" with password "letmein" Scenario: Run fizzbuzz past anonymous limit When I run fizzbuzz on range "95" to "102" Then I should see "Buzz Fizz 97 98 Fizz Buzz 101 Fizz" Scenario: Cannot exceed maximum range When I run fizzbuzz on range "1" to "302" Then I should see "The range you requested is beyond the maximum… And I should see "298 299 FizzBuzz 301" But I should not see "299 FizzBuzz 301 302" 

//features/bootstrap/FeatureContext.php

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. 

Example 3. 

The FizzBuzzer Because, really, people will fund anything 

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Anonymous users can run FizzBuzz but only up to to the number 100 

Whether the job is big or small, do it right or not at all 

Identify Change Points 

FizzBuzz!

Result



Write Pinning Tests 

Feature: Anonymous Run FizzBuzz As a non-registered fizzbuzz enthusiast I need to be able to run fizzbuzz on a range of numbers So that I can get my fix of fizzbuzziness Scenario: Anonymous users should be able to run the fizzbuzzer When I am on homepage And I run fizzbuzz on range "12" to "20" Then I should see "Fizz 13 14 FizzBuzz 16 17 Fizz 19 Buzz" Scenario: Anonymous users should be able to run a second fizzbuzz When I am on homepage And I run fizzbuzz on range "3" to "5" Then I should see "Fizz 4 Buzz" When I run fizzbuzz on range "9" to "12" Then I should see "Fizz Buzz 11 Fizz" 

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Refactor and Make Changes 

Then I should see "Fizz 13 14 FizzBuzz 16 17 Fizz 19 Buzz" Scenario: Anonymous users should be able to run a second fizzbuzz When I am on homepage And I run fizzbuzz on range "3" to "5" Then I should see "Fizz 4 Buzz" When I run fizzbuzz on range "9" to "12" Then I should see "Fizz Buzz 11 Fizz" Scenario: Anonymous users should not be able to exceed 100 When I am on homepage And I run fizzbuzz on range "95" to "101" Then I should see "101 is beyond the maximum value, 100" And I should see "Buzz Fizz 97 98 Fizz Buzz" 

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class FizzBuzzTest extends \PHPUnit_Framework_TestCase { /** * @test */ public function normalizeRangeForAnonShouldTruncateAt100() { $normalizedRange = fizzbuzz_normalize_range(95, 101, false); $this->assertTrue($normalizedRange['can_process']); $this->assertEquals(100, $normalizedRange['end']); } /** * @test */ public function signedInUsersCanUseIntegersOver100() { $range = fizzbuzz_normalize_range(95, 101, true); $this->assertTrue($range['can_process']); $this->assertEquals(101, $range['end']); } } 

function fizzbuzz_normalize_range($start, $end, $is_user = false) { $can_process = true; $message = ''; if (!$is_user) { //anon can only fizzbuzz for ranges up to 100 if ($end > 100) { $message = '$end.'is 'beyond the maximum value, 100” $end = 100; } } return array( 'can_process' => $can_process, 'message' => $message, 'start' => $start, 'end' => $end, ); } 

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+3 feature tests +2 Unit tests Added 

Freedom to Refactor FEARLESSLY 

Create Abstractions expose the API you want, guided by tests 



rangeProcessor = new \FizzBuzzer\RangeProcessor(); } /** * @test */ public function shouldReturnValuesForSimpleRange() { $this->assertEquals( array(1, 2, 'Fizz', 4, 'Buzz'), $this->rangeProcessor->process(1, 5) ); } } 

class RangeProcessor { public function process($start, $end) { $results = array(); foreach (range($start, $end) as $number) { $results[] = $this->fizzbuzzFor($number); } return $results; } private function fizzbuzzFor($number) { if ($number % 15 === 0) { return 'FizzBuzz'; } elseif ($number % 3 === 0) { return 'Fizz'; } elseif ($number % 5 === 0) { return 'Buzz'; } return $number; } } 

function fizzbuzz_for_range($start, $end) { $f = array(); for ($i = $start; $i <= $end; $i++) { $f[] = fizzbuzz_of($i); } return $f; } 

function fizzbuzz_for_range($start, $end) { $processor = new RangeProcessor(); return $processor->process($start, $end); } 

Break Dependencies creating seams is your friend 

namespace Fizzbuzzer; class Order { public $id; public function getPayments() { $paymentDao = new PaymentDao(); return $paymentDao->getOrderPayments($this->id); } } 

namespace tests\Fizzbuzzer; use Fizzbuzzer\Order; class OrderTest extends \PHPUnit_Framework_TestCase { /** @test */ public function shouldReturnPaymentsAppliedToOrder() { $o = new Order(); $this->assertNotEmpty($o->getPayments()); } } 

class Order { public $id; public function getPayments() { $paymentDao = $this->getPaymentDao(); return $paymentDao->getOrderPayments($this->id); } protected function getPaymentDao() { return new PaymentDao(); } } 

class Order { public $id; public function getPayments() { $paymentDao = $this->getPaymentDao(); return $paymentDao->getOrderPayments($this->id); } public function setPaymentDao(PaymentDao $paymentDao) { $this->paymentDao = $paymentDao; } protected function getPaymentDao() { if (null === $this->paymentDao) { $this->paymentDao = new PaymentDao(); } return $this->paymentDao; } } 

class OrderTest extends \PHPUnit_Framework_TestCase { /** @test */ public function shouldReturnPaymentsAppliedToOrder() { $paymentDao = $this->getMock('\\Fizzbuzzer\\PaymentDao'); $paymentDao->expects($this->any()) ->method('getOrderPayments') ->will($this->returnValue(array( $this->getMock('\\Fizzubzzer\\Payment') ))); $o = new Order(); $o->setPaymentDao($paymentDao); $this->assertNotEmpty($o->getPayments()); } } 

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. 

Thanks. http://speakerdeck.com/jcarouth Q&A http://joind.in/9059 Jeff Carouth // @jcarouth // #zendcon13