Dealing with Testing Fatigue #mm18pl

Slides from Meet Magento Poland 2018

30 Minutes Presentation. Video will be available later, follow https://twitter.com/meetmagentopl

Transcript

1. Dealing With Testing Fatigue Fabian Schmengler
2. Fabian Schmengler Developer and partner at integer_net, Germany Testing Magento since 2011 Magento Master 2017-2018 @fschmengler
3. Did you know? 3 / 60 #MM18PL 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 / 60 #MM18PL 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 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
6. 6 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
7. 7 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
8. Why all the frustration? 8 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
9. http://xunitpatterns.com/ "Test smells" Project smells Behavior smells Code smells 9 / 60 #MM18PL 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 / 60 #MM18PL 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 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
12. I've been through it, too... 12 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
13. ...but did I give up? 13 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
14. ...but did I give up? NOPE There's a way out! 13 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
15. (It's not easy!) 14 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
16. First and foremost: Learn! Testing is a different skill than coding 15 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
17. Test the right things! No, "everything" is not the answer 16 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
18. Write testable code! If code is hard to test, make it easy to test 17 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
19. Write testable code Dependency Injection 18 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
20. Write testable code Dependency Inversion 19 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
21. Write testable code Ports & Adapters 20 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
22. Improve test architecture Know your (anti-)patterns 21 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
23. 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 22 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
24. Fixture setup strategy Prebuilt xture Shared xture Fresh xture 23 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
25. Fixture setup strategy Prebuilt xture e.g. Magento integration test database Shared xture Fresh xture 24 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
26. Fixture setup strategy Prebuilt xture Shared xture shared by whole test suite OR shared by test case Fresh xture 25 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
27. Fixture setup strategy Prebuilt xture Shared xture Fresh xture Inline in test method Implicitly in setUp() 26 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
28. 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 27 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
29. 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 28 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
30. Problem increasing cost of changes Possible solutions Extract class refactoring In setup: Test data builder In veri cation: Custom constraint 29 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
31. 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 ); } } 30 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
32. Testing pattern Constraint Usage $this->assertThat(42, new IsMeaningOfLife()); 31 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
33. Testing pattern Test data builder Creates xture, reusable across tests 32 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
34. Test data builder Example CustomerBuilder::aCustomer() ->withEmail('test@example.com') ->withCustomAttributes( [ 'my_custom_attribute' => 42 ] ) ->build() https://github.com/tddwizard/magento2- xtures 33 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
35. Testing smell Irrelevant information 34 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
36. $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') ); 35 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
37. Problem Hard to read test as documentation Possible solutions Extract creation methods or assertions with relevant parameters For xtures: Test data builder 36 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
38. Testing Smell Hard-coded test data public function testGetTranslationFileTimestamp() { $this->fileManagerMock->expects($this->once()) ->method('getTranslationFileTimestamp') ->willReturn(1445736974); $this->assertEquals(1445736974, $this->model->getTranslationFileTimestamp()); } 37 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
39. Problem Hard to understand cause and effect Purpose of typical test data (foo, bar, 1, 42) is unclear Possible solutions Introduce variables or constants 38 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
40. Testing smell Mystery guest Set up or veri cation relies on information that's not visible in the test Filename Database record General xture 39 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
41. Mystery Guest Filename public function testBundleImport() { // import data from CSV file $pathToFile = __DIR__ . '/../../_files/import_bundle.csv'; // ... } 40 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
42. Mystery Guest Database record / General Fixture /** * @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); } 41 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
43. 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 For shared xture: Accurately named nder methods 42 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
44. Shared 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; } 43 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
45. 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()); 44 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
46. Problem Hard to tell apart setup, exercise and veri cation Harder to localize defects Possible solutions Single condition tests 45 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
47. Testing pattern Given...When...Then... $this->given_stock_item_with_qty(2); $this->when_stock_item_is_changed_to(0); $this->then_loaded_stock_item_qty_should_be('0.0000'); Readable high level test methods Clear phases: setup (given), exercise (when) and veri cation (then) Convert variables ($savedStockItem) to properties Additional methods can also start with and_ 46 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
48. 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); 47 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
49. 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 48 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
50. Testing pattern Fake object Test speci c implementation without external dependencies 49 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
51. 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; } } 50 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
52. 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 51 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
53. Testing Smell Meaningless test names public function testProcessValidStoreCodeCase1() { // ... } public function testProcessValidStoreCodeCase2() { // ... } public function testProcessValidStoreCodeCase3() { // ... } 52 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
54. 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' => [ ... ], ] 53 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
55. Testing Smell Meaningless assertion messages Failed asserting that 0 is 1. Failed asserting that false is true. 54 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
56. Problem Failures in test results are unclear Possible solutions use the $message parameter in assert methods to add custom message 55 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
57. Testing smell Conditional test logic public function testSend($configValue, $forceSyncMode, $isComment, $sendingResult) { // ... if (!$isComment) { // ... } // ... if (!$configValue || $forceSyncMode) { // ... if ($sendingResult) { // ... } else { // ... } } else { // ... } } 56 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
58. 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 57 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
59. More smells Test logic in production General xture Using resources (DB, HTTP) in unit tests Indirect testing "Inappropiate intimacy" 58 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
60. 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. 59 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler
61. Image sources Head in sand: tropical.pete @Flickr CC-BY-SA 2.0 60 / 60 #MM18PL Fabian Schmengler /> Dealing With Testing Fatigue @fschmengler