The Myth of Untestable Code

Transcript

1. MYTH CODE UNTESTABLE THE OF
2. SEBASTIAN BERGMANN SEBASTIAN HEUER CREATOR OF PHPUNIT CO-FOUNDER OF THEPHP.CC DEVELOPER ADVOCATE DIE KARTENMACHEREI
5. TESTING CLEAN CODE IS EASY
6. Headline LEGACY HELL
7. TEMPLATE NEW
8. template_new.php
10. IDML FO PNG PDF
11. PDF PNG FO
16. 1 <?php 2 use Content\CraftPaper\CraftPaper; 3 use Content\CraftPaper\InputTextFo; 4 use Content\DomainRemover\DomainRemover; 5 use Content\FlipCalendar\FlipCalendar; 6 use Content\FlipCalendar\Pdf; 7 use Content\FlipCalendar\ShellCommands; 8 use Content\Logging\Error; 9 use Content\Loggly\LogglyClient; 10 use Content\Loggly\LogglyToken; 11 use Content\RenderLock\FakeLock; 12 use Content\RenderLock\RealLock; 13 use Content\Shared\ConfigurationId; 14 use Content\Shared\ConfigurationIdChecker; 15 use Content\Shared\ConfigurationPathBuilder; 16 use Content\Shared\ContentDomain; 17 use Content\Shared\OrderItemId; 18 use Content\Shared\OrderToolDomain; 19 use Content\Shared\Status; 20 use Content\Shared\TemplatePath; 21 22 error_reporting(E_ALL); 23 24 ini_set('memory_limit', '2048M'); 25 ini_set('post_max_size', '64M'); 26 ini_set('upload_max_filesize', '64M'); 27 28 require_once '../../../config.php'; 29 require_once 'idml.php'; 30 require_once '../../../helper/logging/Logging.php'; 31
17. (…) 2777 if ($isTranslationTool === false) { 2778 if (file_exists($configurationPath . 'spot' . $filenameSuffix . '.pdf')) { 2779 if ($isDebugMode) { 2780 echo $configurationPath . 'spot' . $filenameSuffix . '.pdf<br/>'; 2781 echo 'GENERATING PAGES ' . $i . ' spot.pdf<br/>'; 2782 } 2783 $pdf->setSourceFile($configurationPath . 'spot' . $filenameSuffix . '.pdf'); 2784 $tplIdx = $pdf->importPage($i + 1); 2785 $pdf->useTemplate($tplIdx, 0, 0); 2786 } elseif (file_exists($template_path . 'spot.pdf')) { 2787 if ($isDebugMode) { 2788 echo $template_path . 'spot.pdf<br/>'; 2789 echo 'GENERATING PAGES ' . $i . ' spot.pdf<br/>'; 2790 } 2791 $pdf->setSourceFile($template_path . 'spot.pdf'); 2792 $tplIdx = $pdf->importPage($i + 1); 2793 $pdf->useTemplate($tplIdx, 0, 0); 2794 } elseif ($isDebugMode) { 2795 echo 'NOT FOUND >> spot.pdf<br/>'; 2796 } 2797 } (…)
18. "The method execute() has an NPath complexity of 42261380675144684438377688955408190012304275410858 3958093751102384903715343564800000." "The configured NPath complexity threshold is 200."
19. FOUR HUNDRED TWENTY-TWO SEXVIGINTILLION, SIX HUNDRED THIRTEEN QUINVIGINTILLION, EIGHT HUNDRED SIX QUATTUORVIGINTILLION, SEVEN HUNDRED FIFTY-ONE TREVIGINTILLION, FOUR HUNDRED FORTY-SIX DUOVIGINTILLION, EIGHT HUNDRED FORTY-FOUR UNVIGINTILLION, THREE HUNDRED EIGHTY-THREE VIGINTILLION, SEVEN HUNDRED SEVENTY-SIX NOVEMDECILLION, EIGHT HUNDRED EIGHTY-NINE OCTODECILLION, FIVE HUNDRED FIFTY-FOUR SEPTENDECILLION, EIGHTY-ONE SEXDECILLION, NINE HUNDRED QUINDECILLION, ONE HUNDRED TWENTY-THREE QUATTUORDECILLION, FORTY-TWO TREDECILLION, SEVEN HUNDRED FIFTY-FOUR DUODECILLION, ONE HUNDRED EIGHT UNDECILLION, FIVE HUNDRED EIGHTY-THREE DECILLION, NINE HUNDRED FIFTY-EIGHT NONILLION, NINETY-THREE OCTILLION, SEVEN HUNDRED FIFTY-ONE SEPTILLION, ONE HUNDRED TWO SEXTILLION, THREE HUNDRED EIGHTY-FOUR QUINTILLION, NINE HUNDRED THREE QUADRILLION, SEVEN HUNDRED FIFTEEN TRILLION, THREE HUNDRED FORTY-THREE BILLION, FIVE HUNDRED SIXTY-FOUR MILLION, EIGHT HUNDRED THOUSAND
20. GLOBAL STATE A GAZILLION EXECUTION PATHS STATIC METHOD CALLS
21. TESTING LEGACY CODE IS HARD impossible?
22. "LET'S JUST REBUILD THIS FROM SCRATCH!"
23. NO DOCUMENTATION ONLY CODE
24. A Clockwork Orange - Ludovico technique; © Warner Bros
26. UNIT do we write the software right?
27. TESTING LEGACY CODE IS HARD impossible?
28. TESTING LEGACY CODE IS HARD Unit-testing unrefactored legacy code is impossible
29. END-TO-END TESTING UNREFACTORED LEGACY CODE IS ALWAYS POSSIBLE
30. ACCEPTANCE INTEGRATION UNIT END-TO-END do we write the right software? do we write the software right? execution time $$$ ¢ maintenance cost
31. do we write the right software? END-TO-END $$$
32. IDML FO PNG PDF
33. 1 <?php 2 class EndToEndTest extends PHPUnit\Framework\TestCase { 3 /** 4 * @backupGlobals enabled 5 */ 6 public function testCreatesExpectedFoFile() { 7 8 $_REQUEST = [ 9 'template_design' => 'KAM11GG', 10 'template_format' => 'F210', 11 'template_color' => 'C06', 12 // (...) 13 ]; 14 15 require __DIR__ .'/../src/template_new.php'; 16 17 $expectedFile = __DIR__ . '/fixtures/expected.fo'; 18 $actualFile = __DIR__ . '/../data/templates/KAM11GG/F210/C06/input.fo'; 19 20 $this->assertFileEquals($expectedFile, $actualFile); 21 } 22 }
34. 1 <?php 2 class EndToEndTest extends PHPUnit\Framework\TestCase { 3 4 /** 5 * @backupGlobals enabled 6 * 7 * @dataProvider inputFoCreationTestProvider 8 * 9 * @param string $design 10 * @param string $format 11 * @param string $color 12 * @param string $expectedFile 13 */ 14 public function testCreatesExpectedInputFoFile($design, $format, $color, $expectedFile) { 15 16 $_REQUEST = [ 17 'template_design' => $design, 18 'template_format' => $format, 19 'template_color' => $color, 20 // (...) 21 ]; 22 23 require __DIR__ .'/../src/template_new.php'; 24 25 $actualFile = sprintf(__DIR__ . '/../data/templates/%s/%s/%s/input.fo', $design, $format, $color); 26 27 $this->assertFileEquals($expectedFile, $actualFile); 28 } 29 }
35. BUT WHAT IF YOU DON'T KNOW INPUT AND/OR OUTPUT?
36. CHARACTERIZATION TESTS "An attempt to lock existing behavior into an untested or undocumented system." http://wiki.c2.com/?CharacterizationTest
38. EXAMPLE
39. 1 <?php 2 function add($a, $b) 3 { 4 return $a + $b; 5 } 6 7 add(1, 2); legacy.php
40. $ php -d xdebug.auto_trace=1 -d xdebug.trace_format=1 \ -d xdebug.collect_params=5 -d xdebug.collect_return=1 legacy.php $ cat /tmp/trace.4251619279.xt Version: 2.5.3 File format: 4 TRACE START [2014-06-27 10:40:40] 1 0 0 0.000282 279896 {main} 1 /home/sb/legacy.php 0 0 2 1 0 0.000371 280136 add 1 /home/sb/legacy.php 7 2 aToxOw== aToyOw== 2 1 1 0.000440 280256 2 1 R aTozOw== 1 0 1 0.000470 280016 1 0 R aToxOw== 0.000648 8488 TRACE END [2014-06-27 10:40:40] $ de-legacy-fy generate-characterization-test add /tmp/trace.4251619279.xt CharacterizationTest CharacterizationTest.php de-legacy-fy 2.0.0 by Sebastian Bergmann. Generated class "CharacterizationTest" in file "CharacterizationTest.php"
41. 1 <?php 2 class CharacterizationTest extends \PHPUnit\Framework\TestCase 3 { 12 /** 13 * @return array 14 */ 15 public function provider() 16 { 17 return array( 18 array($this->decode('aTozOw=='), $this->decode('aToxOw=='), $this->decode('aToyOw==')) 19 ); 20 } 21 22 /** 23 * @param string $value 24 * @return mixed 25 */ 26 private function decode($value) 27 { 28 return unserialize(base64_decode($value)); 29 }
 30 31 32 33 34 35 36 37 38 } 31 /** 32 * @dataProvider provider 33 */ 34 public function testAddFunctionWorksLikeItUsedTo($expected, $a, $b) 35 { 36 $this->assertEquals($expected, add($a, $b)); 37 }
42. BACK TO OUR CASE
43. NEXT: REFACTOR TO ALLOW INTEGRATION TESTING
44. MOVE CODE INTO CLASS
45. 1 <?php 2 class TemplateNew { 3 public function execute() { 4 $oConfig = new Config(); 5 $configurationIdChecker = new ConfigurationIdChecker(); 6 7 /** 8 * @deprecated $_REQUEST['template_format']. Use $_REQUEST['format'] 9 * TODO see WEDS-609 10 */ 11 $templateFormatParameter = isset($_REQUEST['format']) ? $_REQUEST['format'] : $_REQUEST['template_format'] 12 /** 13 * @deprecated $_REQUEST['template_design']. Use $_REQUEST['design'] 14 * TODO see WEDS-609 15 */ 16 $templateDesignParameter = isset($_REQUEST['design']) ? $_REQUEST['design'] : $_REQUEST['template_design'] 17 /** 18 * @deprecated $_REQUEST['template_color']. Use $_REQUEST['color'] 19 * TODO see WEDS-609 20 */ 21 $templateColorParameter = isset($_REQUEST['color']) ? $_REQUEST['color'] : $_REQUEST['template_color']; 22 23 $basePath = substr($oConfig->getBasePath(), 0, -1); // remove ending slash 24 $configurationRoot = $oConfig->getConfigByPath('path/configurations'); 25 $templateRoot = ''; // setted up in line 382 (template switch) 26 $sFopConfigRelative = $oConfig->getConfigByPath('path/fop/config'); 27 $sFopConfigAbsolute = $basePath . '/' . $sFopConfigRelative; 28 $usedDieCut = (isset($_REQUEST['diecut']) && !empty($_REQUEST['diecut']) && 'D53' == $_REQUEST['diecut'] ? 29 $_REQUEST['diecut'] : ''); 30 $configurationID = (isset($_REQUEST['configurationID'])) ? $_REQUEST['configurationID'] : null;
46. INTRODUCE DEPENDENCY INJECTION
47. 1 <?php 2 class TemplateNew { 3 /** @var TemplateNewConfig */ 4 private $config; 5 /** @var IDML */ 6 private $idmlParser; 7 /** @var TemplateNewRequest */ 8 private $request; 9 10 /** 11 * @param TemplateNewConfig $config 12 * @param IDML $idmlParser 13 * @param TemplateNewRequest $request 14 */ 15 public function __construct(TemplateNewConfig $config, IDML $idmlParser, TemplateNewRequest $request) { 16 $this->config = $config; 17 $this->idmlParser = $idmlParser; 18 $this->request = $request; 19 } 20 21 public function execute() { 22 $configurationIdChecker = new ConfigurationIdChecker(); 23 24 $templateFormatParameter = $this->request->getFormat(); 25 $templateDesignParameter = $this->request->getDesign(); 26 $templateColorParameter = $this->request->getColor(); 27 28 $basePath = substr($this->config->getBasePath(), 0, -1); // remove ending slash 29 $configurationRoot = $this->config->getConfigByPath('path/configurations'); 30 $templateRoot = ''; // setted up in line 382 (template switch) 31 $sFopConfigRelative = $this->config->getConfigByPath('path/fop/config');
48. ACCEPTANCE INTEGRATION END-TO-END do we write the right software? do we write the software right? execution time $$$ ¢ maintenance cost
49. USE TESTS TO WRITE NEW CODE
50. CODE COVERAGE REPORT
53. Webserver Legacy Code FO
54. Webserver Legacy Code New Code Abstraction Layer FO
55. Webserver Legacy Code New Code Abstraction Layer $format === 'F040' FO
56. BRANCH BY ABSTRACTION
57. SUMMARY
58. MEANINGFUL TESTS ARE A VALUABLE SOURCE OF DOCUMENTATION
59. INTEGRATION TESTS ALLOW YOU TO WRITE NEW, CLEAN CODE
60. USE BRANCH BY ABSTRACTION TO GRADUALLY MOVE FUNCTIONALITY TO NEW CODE
61. WRITE UNIT TESTS FOR NEW CODE
62. TESTING CLEAN CODE IS EASY
63. THANK YOU! @inside_kam @belanur @thePHPcc @s_bergmann