Dealing with Testing Fatigue

Slides from MageTestFest

1. Dealing With Testing Fatigue MAGE TEST FEST Fabian Schmengler
2. Fabian Schmengler Developer and partner at integer_net Testing Magento since 2011 Magento Master 2017 @fschmengler
3. Did you know? 3 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
4. What I'm hearing a lot: “ I'd really like to write more tests but I don't get any practical value from them. It takes too much time, or it is too hard. Therefore I don't enjoy it or stopped doing it. (I totally understand that!) 4 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
5. Another popular opinion: ‘ Integration tests are superior to unit tests. Do not waste your time with unit tests. (at least they are writing tests!) 5 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
6. 6 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
7. Spoiler: A healthy mix of tests is best Things are mostly ne 07:32 - 21. Mai 2016 36 5.588 5.472 The Practical Dev @ThePracticalDev 7 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
8. Why all the frustration? 8 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
9. http://xunitpatterns.com/ "Test smells" Project smells Behavior smells Code smells 9 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
10. Why all the frustration? The project smells Buggy tests High test maintenance cost Production bugs Developers not writing tests 10 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
11. Why all the frustration? The behavior smells Fragile Test Erratic Test Slow Test Frequent Debugging Manual Intervention 11 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
12. I've been through it, too... 12 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
13. ...but did I give up? 13 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
14. ...but did I give up? NOPE There's a way out! 13 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
15. (It's not easy!) 14 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
16. First and foremost: Learn! Testing is a different skill than coding 15 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
17. Test the right things! No, "everything" is not the answer 16 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
18. Write testable code! If code is hard to test, make it easy to test 17 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
19. Write testable code Dependency Injection 18 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
20. Write testable code Dependency Inversion 19 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
21. Write testable code Ports & Adapters 20 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
22. 21 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
23. 22 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
24. Improve test architecture Know your (anti-)patterns 23 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
25. Test phases 1. Setup set up xture (instantiate objects) 2. Exercise interact with subject under test (SUT) 3. Verify assertions 4. Teardown clean up xture 24 / 62
26. Fixture setup strategy Prebuilt xture Shared xture Fresh xture 25 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
27. Fixture setup strategy Prebuilt xture e.g. Magento integration test database Shared xture Fresh xture 26 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
28. Fixture setup strategy Prebuilt xture Shared xture shared by whole test suite e.g. Magento integration test object manager, Magento unit test code generation shared by test case setUpBeforeClass(), or lazy setup Fresh xture 27 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
29. Fixture setup strategy Prebuilt xture Shared xture Fresh xture Inline in test method Implicitly in setUp() 28 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
30. Testing smell Copy and paste Duplicated logic in test code dev/tests/integration/testsuite/Magento/Customer/_files/customer.php dev/tests/integration/testsuite/Magento/Customer/_files/two_customers.php dev/tests/integration/testsuite/Magento/Customer/_files/three_customers.php dev/tests/integration/testsuite/Magento/Customer/_files/twenty_one_customers.php 29 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
31. Problem increasing cost of changes Possible solutions Extract method refactoring In setup: Creation method for fresh xture Finder method for shared xture In veri cation: Custom assertion method 30 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
32. Problem increasing cost of changes Possible solutions Extract class refactoring In setup: Test data builder In veri cation: Custom constraint 31 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
33. Testing pattern Constraint class IsMeaningOfLife extends \PHPUnit\Framework\Constraint { protected function matches($other) { return $other === 42; } protected function failureDescription($other) { return sprintf( "%s is not the meaning of life, the universe and everything", $other ); } } 32 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
34. Testing pattern Constraint Usage $this->assertThat(42, new IsMeaningOfLife()); 33 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
35. Testing pattern Test data builder Creates xture, reusable across tests 34 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
36. Test data builder Example CustomerBuilder::aCustomer() ->withEmail('test@example.com') ->withCustomAttributes( [ 'my_custom_attribute' => 42 ] ) ->build() https://github.com/tddwizard/magento2- xtures 35 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
37. Testing smell Irrelevant information 36 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
38. $customer->setWebsiteId( 1 )->setId( 1 )->setEntityTypeId( 1 )->setAttributeSetId( 1 )->setEmail( 'customer@example.com' )->setPassword( 'password' )->setGroupId( 1 )->setStoreId( 1 )->setIsActive( 1 )->setFirstname( 'Firstname' )->setLastname( 'Lastname' )->setDefaultBilling( 1 )->setDefaultShipping( 1 )->setRpToken( '8ed8677e6c79e68b94e61658bd756ea5' )->setRpTokenCreatedAt( date('Y-m-d H:i:s') ); 37 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
39. Problem Hard to read test as documentation Possible solutions Extract creation methods or assertions with relevant parameters For xtures: Test data builder 38 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
40. Testing Smell Hard-coded test data public function testGetTranslationFileTimestamp() { $this->fileManagerMock->expects($this->once()) ->method('getTranslationFileTimestamp') ->willReturn(1445736974); $this->assertEquals(1445736974, $this->model->getTranslationFileTimestamp()); } 39 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
41. Problem Hard to understand cause and effect Possible solutions Introduce variables or constants 40 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
42. Testing smell Mystery guest Set up or veri cation relies on information that's not visible in the test Filename Database record General xture 41 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
43. Mystery Guest Filename public function testBundleImport() { // import data from CSV file $pathToFile = __DIR__ . '/../../_files/import_bundle.csv'; // ... } 42 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
44. Mystery Guest Database record /** * @magentoAppArea adminhtml * @magentoDataFixture Magento/Reports/_files/viewed_products.php */ public function testExecute() { $this->dispatch('backend/admin/dashboard/productsViewed/'); $this->assertEquals(200, $this->getResponse()->getHttpResponseCode()); $actual = $this->getResponse()->getBody(); $this->assertContains('Simple Product', $actual); } 43 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
45. Problem Hard to understand cause and effect Risk of somebody else editing external source without knowing how it's used Possible solutions Fresh xture for each test Test data builders instead of xture scripts Create les in test Accurately named nder methods 44 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
46. General Fixture Using attribute $this->assertTrue($this->product->isNew(), 'Product should be new'); Using nder method $this->assertTrue( $this->getRecentlyAddedProduct()->isNew(), 'Product should be new' ); private function getRecentlyAddedProduct() { return $this->product; } 45 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
47. Testing smell Eager test $savedStockItem->setQty(null); $savedStockItem->save(); $savedStockItem->setQty(2); $savedStockItem->save(); $this->assertEquals('2.0000', $savedStockItem->load($savedStockItemId)->getQty()); $savedStockItem->setQty(0); $savedStockItem->save(); $this->assertEquals('0.0000', $savedStockItem->load($savedStockItemId)->getQty()); $savedStockItem->setQty(null); $savedStockItem->save(); $this->assertEquals(null, $savedStockItem->load($savedStockItemId)->getQty()); 46 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
48. Problem Hard to tell apart set up, exercise and veri cation Harder to localize defects Possible solutions Single condition tests Create one test case (class) per case, not per subject 47 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
49. Testing smell Excessive Mocking $baseCurrency->expects()->method('getCode')->willReturn('USD'); $baseCurrency->expects()->method('getCurrencySymbol')->willReturn('$'); $baseCurrency->expects()->method('getRate')->with('AUD')->willReturn('0.80'); $store->expects()->method('getBaseCurrency')->willReturn($baseCurrency); $store->expects()->method('getDefaultCurrency')->willReturn($baseCurrency); $store->expects()->method('getAvailableCurrencyCodes')->willReturn(['AUD']); $this->storeManager->expects()->method('getStore')->willReturn($store); 48 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
50. Problem Coupling test to implementation Test is hard to read Possible solutions Use real domain objects where possible Refactor production code Use custom stub or fake objects with simpler setup 49 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
51. Testing pattern Fake object Test speci c implementation without external dependencies 50 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
52. Fake object interface CustomerSession { public function isLoggedIn() : bool; } class FakeSession implements CustomerSession { private $loggedIn = false; public function isLoggedIn() : bool { return $this->loggedIn; } // test methods: public function login() { $this->loggedIn = true; } public function logout() { $this->loggedIn = false; } } 51 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
53. Fake object PHPUnit stub: $session = $this->createMock(CustomerSession::class); $session->method('isLoggedIn')->willReturn(true); Custom fake: $session = new FakeSession(); $session->login(); more succinct reusable accross tests 52 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
54. Testing Smell Meaningless test names public function testProcessValidStoreCodeCase1() { // ... } public function testProcessValidStoreCodeCase2() { // ... } public function testProcessValidStoreCodeCase3() { // ... } 53 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
55. Problem Failures in test results are unclear Possible solutions Write meaningful test names Use named keys in data provider arrays return [ 'meaningful description of case 1' => [ ... ], 'meaningful description of case 2' => [ ... ], ] 54 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
56. Testing Smell Meaningless assertion messages Failed asserting that 0 is 1. Failed asserting that false is true. 55 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
57. Problem Failures in test results are unclear Possible solutions use the $message parameter in assert methods to add custom message 56 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
58. Testing smell Conditional test logic public function testSend($configValue, $forceSyncMode, $isComment, $sendingResult) { // ... if (!$isComment) { // ... } // ... if (!$configValue || $forceSyncMode) { // ... if ($sendingResult) { // ... } else { // ... } } else { // ... } } 57 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
59. Problem Harder to understand the test Harder to write the test correctly Possible solutions Write separate test cases, extract duplicated logic Make sure, tests are deterministic 58 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
60. More smells Test logic in production General xture Using resources (DB, HTTP) in unit tests Indirect testing "Inappropiate intimacy" 59 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
61. Conclusion Maintainability and stability of tests can be greatly improved by taking care of the test architecture. Watch out for these typical problems. Get rid of them. MAKE TESTING FUN 60 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
62. Conclusion Maintainability and stability of tests can be greatly improved by taking care of the test architecture. Watch out for these typical problems. Get rid of them. MAKE TESTING FUN AGAIN 60 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
63. THANK YOU 61 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
64. THANK YOU Coming soon: Test Driven Magento by Example http://tddwizard.com/ @fschmengler 61 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
65. Image sources Head in sand: tropical.pete @Flickr CC-BY-SA 2.0 62 / 62 Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler