Vertical Slice testing at Agilia 2015

A presentation for the "Unit testing is out, Vertical Slice Testing is in" talk at Agilia 2015

Transcript

1. March 2015 Unit Testing is out Vertical Slice Testing is in
2. I’m Marcin Floryan http://marcin.floryan.pl
3. mfloryan @
4. Do you test your code?
5. Are you writing automated tests?
6. Do you code test-first?
7. Do you practice TDD?
8. An experienced team of developers
9. 18 months pair-programming TDD
10. 635 tests 3,500 LOC
14. What is your favorite mocking framework?
22. •  HomenetFormParameterBuilderTests •  ShouldBuildUrlForHomenet •  ProcessProviderResponseHandlerTests •  ShouldExecuteCommandAgainstProviderQuote •  Should_save_events_with_consistant_hash_of_enqu iryId •  PanelServiceTests •  ShouldReturn404WhenTryingToRecordBrandQuoteDisp layedForEnquiryThatDoesntExist •  ShouldReturn404WhenTryingToRecordBrandQuoteDisp layedForEnquiryUsingNoContentType •  ShouldReturn400WhenTryingToRecordBrandQuoteDisp layedWhenBrandListContainsAnUnexpectedBrand •  ShouldReturn200WhenTryingToRecordNoBrandQuoteDi splayedForEnquiry
23. Tests became brittle
24. Test suite grew and slowed down
25. Tests lost readability
26. TDD is dead
28. VEST
29. VErtical Slice Testing http://codebetter.com/sebastienlambla/2013/07/11/unit-testing-is-out-vertical-slice-testing-is-in/
30. Vertical Slice single behaviour of your system
31. Test outside-in and end to end with thin behavioural tests
32. ports and adapters architecture
33. External components in memory
34. Internal components in memory
35. Internal components in memory •  Database •  File system •  Network •  Message bus
37. Use libraries that provide accurate in-memory test adapters or write them yourself
38. explicit contracts with external resources
39. ports and adapters architecture
40. Use language of the domain
41. Diagnosing When sending ping Then pong is received and server version is announced
43. Missing product identifier When starting recon Then error response is returned
44. Test code conventions •  Test setup in the constructor •  GIVEN methods setup state of the system •  Single WHEN method acts on the system •  Asserts in traditional [Test] methods – THEN •  Functionality expressed using domain language •  A base class called context abstracts implementations of tests behaviours
45. Latest enquiries Given multiple enquiries made When retrieving latest enquiries Then up to ten latest enquiries are retrie ved and latest enquiries are retrieved in corre ct order
48. 250 tests 2000 LOC
49. Number of tests illustrates progress
50. Our tests are now easier to understand by business users. They are easier to understand by us.
51. I feel like we’re finally doing unit testing in the true sense, the way I always thought it could work.
52. Our tests break when behaviours break, not when implementation changes
53. The test contexts are sometimes tricky to write but once you get them right they are invaluable
54. We don’t do integration testing, instead we have run- time health-checks
55. Before I used to write new tests for every piece of functionality I would implement…
56. …now I think more about changes of behaviour and modify or add to existing tests
57. VETS in a nutshell • Speak language of the domain • Test outside-in and end-to-end • Test thin slices of system’s behaviour • Create DSL to express your tests • Use behaviourally accurate in- memory adapters (no I/O) • Compose your system of loosely coupled coherent components
58. “TDD is dead” is dead
59. Thank you! marcin.floryan.pl @mfloryan come and work with us