Testing Best Practices, or The Five Habits of Highly Effective Tests

There’s all kinds of discussion on how to make test processes work, and how to make tests fast, but it sometimes seems like there’s not much discussion on how to make tests useful. What makes a BDD test valuable, in that it will save more time that it will cost in maintenance? I’ll claim that there are five things that you should look for in your tests: independence, repeatability, clarity, conciseness, and robustness. These features will make the tests easier to write, easier to verify, and easier to keep consistent as your application becomes more complicated. You’ll leave this talk ready and able to write great tests.

Transcript

1. Testing Best Practices or The 5 Habits of Highly Effective Tests Noel Rappin @noelrap Wednesday, April 25, 12
2. What is an "effective" test? Wednesday, April 25, 12
3. "I get paid for code that works, not for tests" -- Kent Beck Wednesday, April 25, 12
4. Effective tests help you sustainably deliver features Wednesday, April 25, 12
5. How do you know tests are effective? Wednesday, April 25, 12
6. Shallow bugs Wednesday, April 25, 12
7. Not staring into space watching dots fly across the screen Wednesday, April 25, 12
8. Relatively little time spent fixing test problems Wednesday, April 25, 12
9. Simple, clean design Wednesday, April 25, 12
10. One thing I didn't say... Wednesday, April 25, 12
11. Coverage Wednesday, April 25, 12
12. BDD is a software design process Wednesday, April 25, 12
13. How do you know your tests aren't effective? Wednesday, April 25, 12
14. Lots of test fragility Wednesday, April 25, 12
15. Test-based slowdowns Wednesday, April 25, 12
16. No confidence in your ability to change Wednesday, April 25, 12
17. Why is testing effective? Wednesday, April 25, 12
18. Expressing requirements in code Wednesday, April 25, 12
19. Universal client Wednesday, April 25, 12
20. Rapid feedback Wednesday, April 25, 12
21. Canary Wednesday, April 25, 12
22. "More Testable" is a legitimate engineering goal Wednesday, April 25, 12
23. Test-Driven vs. Test First Wednesday, April 25, 12
24. What makes for an effective test? Wednesday, April 25, 12
25. Tests are code without tests! Wednesday, April 25, 12
26. Tests have two lives Wednesday, April 25, 12
27. 1. While you are creating the feature Wednesday, April 25, 12
28. 2. Until the heat death of the universe Wednesday, April 25, 12
29. All tests have costs Some tests have value Wednesday, April 25, 12
30. Simple Well-defined Independent Fast Truthful Wednesday, April 25, 12
31. Simple Wednesday, April 25, 12
32. A test is simple if its purpose is immediately clear simple Wednesday, April 25, 12
33. Fixtures Long tests Bad naming Clever simple Wednesday, April 25, 12
34. Good naming Factories Refactoring tests simple Wednesday, April 25, 12
35. If the tests can't be simple, the code is bad simple Wednesday, April 25, 12
36. Tests not written via TDD often have trouble being simple simple Wednesday, April 25, 12
37. Well-defined Wednesday, April 25, 12
38. A test is well-defined if it gives the same result every time well-defined Wednesday, April 25, 12
39. Dates Random well-defined Wednesday, April 25, 12
40. Encapsulation Mocks well-defined Wednesday, April 25, 12
41. Independent Wednesday, April 25, 12
42. A test is independent if it does not depend on external state independent Wednesday, April 25, 12
43. Global data Fixtures independent Wednesday, April 25, 12
44. Factories Teardown/ Transactions independent Wednesday, April 25, 12
45. Fast Wednesday, April 25, 12
46. A test is fast if it is fast fast Wednesday, April 25, 12
47. Too many objects Databases Third Party Frameworks fast Wednesday, April 25, 12
48. Encapsulation Unit testing fast Wednesday, April 25, 12
49. If your tests are not fast, you can not be test-driven fast Wednesday, April 25, 12
50. Truthful Wednesday, April 25, 12
51. A test is truthful if it accurately reflects the underlying code truthful Wednesday, April 25, 12
52. Too specific Mocks Surface values truthful Wednesday, April 25, 12
53. Indirect testing Defensive mocking Understanding requirements truthful Wednesday, April 25, 12
54. Test both sides of a problem Wednesday, April 25, 12
55. The testing pyramid and chains of responsibility Wednesday, April 25, 12
56. Noel Rappin @noelrap railsrx.com Wednesday, April 25, 12