Beyond Unit Testing - The Real Value of TDD - Client Talk

Twenty years after the public introduction of Test-Driven Development (TDD), in Kent Beck's Extreme Programming Explained, it remains a commonly misunderstood and underutilized practice. While there are many who espouse the benefits of TDD, misconceptions about the practice and its perceived learning curve serve to dampen its impact on the software industry.

This talk introduces the misconceptions about TDD, as being just another way to write unit tests. It disputes this belief by refocusing on the many benefits of the practice. The talk will detail the resulting sustainable, high-quality test suites that are a product of TDD. Additionally, it will describe the less visible benefits like software design feedback, and improvements to development structure and developer workflow; all of which are possible through the continued practice of TDD.

If you are a software engineer or a technical leader wanting to learn more about TDD, looking for the motivation to give the practice a try, or are looking for ways to encourage your team(s) to learn the practice, this talk is for you.

Transcript

1. Beyond Unit Testing The Real Value of Test-Driven Development Anthony Sciamanna Senior Consultant Industrial Logic June 8, 2021
2. TDD Refresher Image by Industrial Logic Senior Consultant - Tim Ottinger @asciamanna anthonysciamanna.com
3. @asciamanna anthonysciamanna.com TDD Refresher
4. TDD Refresher @asciamanna anthonysciamanna.com
5. TD Refresher Let’s go back in time! @asciamanna anthonysciamanna.com
6. TD Refresher A Very Brief History of TDD 1994 Kent Beck releases the first version of the SUnit framework for Smalltalk @asciamanna anthonysciamanna.com
7. TD Refresher A Very Brief History of TDD 1994 1995 Kent demos TDD to Ward Cunningham at OOPSLA Austin in October. Details of the C3 Project start being publicized Kent Beck releases the first version of the SUnit framework for Smalltalk @asciamanna anthonysciamanna.com
8. TD Refresher A Very Brief History of TDD 1994 1995 1997 Kent demos TDD to Ward Cunningham at OOPSLA Austin in October. Details of the C3 Project start being publicized Kent Beck releases the first version of the SUnit framework for Smalltalk On a flight from Zurich to Atlanta (OOPSLA ‘97) Erich Gamma and Kent Beck create JUnit for Java @asciamanna anthonysciamanna.com
9. TD Refresher A Very Brief History of TDD 1994 1995 1997 1999 Kent demos TDD to Ward Cunningham at OOPSLA Austin in October. Details of the C3 Project start being publicized Kent Beck releases the first version of the SUnit framework for Smalltalk On a flight from Zurich to Atlanta (OOPSLA ‘97) Erich Gamma and Kent Beck create JUnit for Java Kent releases Extreme Programming Explained @asciamanna anthonysciamanna.com
10. TDD Is a Testing Practice @asciamanna anthonysciamanna.com
11. @asciamanna anthonysciamanna.com I don’t care if people write tests first or last. As long as they get written. - Anonymous Tech Lead
12. @asciamanna anthonysciamanna.com Ignores Design and Workflow Benefits of TDD
13. Benefits of TDD @asciamanna anthonysciamanna.com
14. Benefits of TDD @asciamanna anthonysciamanna.com Externally Visible Artifacts Test Suite
15. Benefits of TDD @asciamanna anthonysciamanna.com Externally Visible Artifacts Test Suite
16. Benefits of TDD Externally Visible Artifacts @asciamanna anthonysciamanna.com Software Design Test Suite
17. Benefits of TDD Externally Visible Artifacts @asciamanna anthonysciamanna.com Developer Workflow Software Design Test Suite
18. Benefits of TDD Externally Visible Artifacts @asciamanna anthonysciamanna.com Developer Workflow Software Design Test Suite
19. TDD Triple Balance anthonysciamanna.com Maker Making Made @asciamanna
20. Benefits of TDD Externally Visible Artifacts anthonysciamanna.com Developer Workflow Software Design Test Suite @asciamanna
21. Test Suite Benefits Why we prefer TDD-style tests over Test After Tests
22. Test Suite Quality Production Code Quality Test suite quality influences production code quality and vice-versa @asciamanna anthonysciamanna.com
23. You Can’t Write Good Tests for Bad Code • Wrapping untestable code in unit tests results in brittle, low-quality tests • Test-first practices enable writing high quality production code and high-quality tests Markus Spiske for Tech Daily @asciamanna anthonysciamanna.com
24. The TDD Quality Cycle Test Suite Production Code 2. Code under test must be testable (loosely coupled) Refactoring Refactoring 3. Enables tests to be small, precise, fast, isolated and independent Virtuous Cycle 1. We start in the test @asciamanna anthonysciamanna.com
25. Microtest A short, simple, fast, isolated*, test that probes the behavior of a single class *Isolated does not mean we have to mock every dependency anthonysciamanna.com @asciamanna
26. Microtests Don’t Access a network Access a database Access the filesystem Depend on other tests Require a complex environment to run in @asciamanna anthonysciamanna.com
27. S O S anthonysciamanna.com @asciamanna
28. Small O S anthonysciamanna.com @asciamanna
29. Small Obvious S anthonysciamanna.com @asciamanna
30. Small Obvious Simple anthonysciamanna.com @asciamanna
31. Small ~12 LOC or less per test @asciamanna anthonysciamanna.com
32. Obvious anthonysciamanna.com @asciamanna
33. Arrange Act Assert Arrange – Act – Assert Or Given - When - Then anthonysciamanna.com @asciamanna
34. Standardize common test constructs Create the object under test in Setup Standard name result to be asserted Standard name for object under test anthonysciamanna.com @asciamanna
35. Simple Avoid branching and flow control logic in tests anthonysciamanna.com @asciamanna
36. How To Stop Hating Your Test Suite Logic in tests confuses the story of what’s being tested. Test- scoped logic is hard to read and errors are easy to miss. - Justin Searls, Co-founder Test Double anthonysciamanna.com @asciamanna
37. How To Stop Hating Your Test Suite Test code is untested code! - Justin Searls, Co-founder Test Double anthonysciamanna.com @asciamanna
38. anthonysciamanna.com @asciamanna Test After Test First Manual testing often takes precedence Unit testing at end tends to be skipped to hit deadlines All code is tested as it is created or modified Feels like busy work if code is manually tested and considered “done” The test is the path to changing the system Code is not influenced by tests to be testable Code is influenced by the tests to be testable Tests don’t serve as feedback loops Tests are continuous feedback loops, supports refactoring and software design Tests don’t get refactored – created at end Tests are continuously refactored Tests are less comprehensive when added at end Tests are more comprehensive when added with each code change Coverage as a build gate often required (commonly 70% coverage) Coverage metrics unnecessary VS.
39. Software Design Benefits Tests guiding quality software design
40. TDD Disclaimer TDD influences design quality But it’s not a magic wand! anthonysciamanna.com @asciamanna
41. TDD Disclaimer TDD influences design quality High Cohesion Loose Coupling Small Classes Small Methods anthonysciamanna.com @asciamanna
42. TDD Disclaimer TDD provides a mechanism for learning software design High Cohesion Loose Coupling Small Classes Small Methods anthonysciamanna.com @asciamanna
43. Practitioners still need to understand the concepts of software design TDD Disclaimer High Cohesion Loose Coupling Code Smells Design Patterns SOLID Refactoring Encapsulation GRASP Connascence anthonysciamanna.com @asciamanna
44. Test-Driven Development Refactoring Legacy Code Techniques Microtesting / Test Suite Design Code Smells Design Patterns Cohesion & Coupling SOLID Continuous Integration Continuous Delivery Evolutionary Design Collaborative Development Iterative Development anthonysciamanna.com @asciamanna
45. Microtests are litmus tests for software design quality @asciamanna anthonysciamanna.com
46. Examples @asciamanna anthonysciamanna.com
47. Too Much Test Setup Too Many Dependencies Too Many Arguments Arguments are Too Complex Code Under Test Doing Too Much anthonysciamanna.com @asciamanna
48. Multiple ‘Act’ Steps Temporal Coupling Exists Complicated API Client needs to know too much about object under test Too Many Steps to Invoke Method Under Test anthonysciamanna.com @asciamanna
49. Too Many Asserts Returning too complex of a type Code under test doing too much anthonysciamanna.com @asciamanna
50. Too Many Test Cases Too much branching logic Code under test is doing too much anthonysciamanna.com @asciamanna
51. Client-First Design / Outside-In TDD enables software design from a client’s perspective Leads to better designed interfaces between objects anthonysciamanna.com @asciamanna
52. Refactoring into design yields a better design than Big Design Up Front Requirements Design Code Test Waterfall Mindset Requirements Test Code Design (Refactor) (Test-Driven) Agile Mindset Slide courtesy of Mike Rieser (@MichaelRieser) anthonysciamanna.com @asciamanna
53. Developer Workflow Benefits Short, fast feedback cycles improve productivity
54. Nearly instantaneous feedback loops anthonysciamanna.com @asciamanna
55. Fast Feedback Loops key to developer productivity & high performing teams anthonysciamanna.com @asciamanna
56. anthonysciamanna.com @asciamanna
57. Resilient to Interruptions anthonysciamanna.com @asciamanna
58. TDD-created Microtests are save states for system functionality anthonysciamanna.com @asciamanna
59. anthonysciamanna.com @asciamanna
60. BIG PROBLEM @asciamanna anthonysciamanna.com
61. BIG PROBLEM @asciamanna anthonysciamanna.com Great software is created by GREAT TEAMS not heroic, rockstar, 10X developers working in isolation
62. BIG PROBLEM @asciamanna anthonysciamanna.com Software development is a communication game Communication is the professional developer’s first order of business. Perhaps you thought that ‘getting it working’ was the first order of business for a professional developer. I hope by now, however, this book has disabused you of that idea. - Robert Martin, Clean Code
63. System is always in a working state anthonysciamanna.com @asciamanna
64. Tiny Validations anthonysciamanna.com @asciamanna
65. https://www.geepawhill.org/2018/04/14/tdd-the-lump-of-coding-fallacy/ anthonysciamanna.com @asciamanna GeePaw Hill – TDD & the Lump of Coding Fallacy
66. https://www.geepawhill.org/2018/04/14/tdd-the-lump-of-coding-fallacy/ anthonysciamanna.com @asciamanna GeePaw Hill – TDD & the Lump of Coding Fallacy
67. https://www.geepawhill.org/2018/04/14/tdd-the-lump-of-coding-fallacy/ anthonysciamanna.com @asciamanna GeePaw Hill – TDD & the Lump of Coding Fallacy
68. https://www.geepawhill.org/2018/04/14/tdd-the-lump-of-coding-fallacy/ anthonysciamanna.com @asciamanna GeePaw Hill – TDD & the Lump of Coding Fallacy
69. Mental Benefits of TDD One of the hardest things to communicate about Test-Driven Development is the mental state it puts you in…On the original C3 project…progress was steady and unhurried; because it was unhurried it seemed slow, but looking back on how much we got done, it was clear that despite the unhurried feeling progress was really fast. “ ” anthonysciamanna.com @asciamanna
70. Mental Benefits of TDD Concrete and visible progress on small incremental goals @asciamanna anthonysciamanna.com
71. Mental Benefits of TDD @asciamanna anthonysciamanna.com Achieving Profluence
72. Mental Benefits of TDD Little or no time spent in the debugger or on repetitive, time consuming manual checks anthonysciamanna.com @asciamanna
73. Learning TDD will help improve software design, developer workflow, increases developer happiness, and it’s a lot of fun! https://geepawhill.org https://github.com/testdouble/contributing-tests/wiki Test Double – Contributing Tests Wiki Industrial Logic eLearning https://www.industriallogic.com/elearning/ anthonysciamanna.com @asciamanna
74. http://bit.ly/beyond-unit-testing-2021 @asciamanna anthonysciamanna.com
75. Attributes • Pygmy Marmoset - https://www.flickr.com/photos/gopak/39889008421 • SOS - https://www.flickr.com/photos/itupictures/16654290295 • Darts - https://www.flickr.com/photos/mike-burns/374198933 • Quote - Nick Youngson CC BY-SA 3.0 • Magician - Photo by Pierrick VAN-TROOST on Unsplash • Litmus test - https://commons.wikimedia.org/wiki/File:Blue_and_red_litmus_paper.JPG • Self-operating napkin - https://upload.wikimedia.org/wikipedia/commons/8/88/Self- operating_napkin_%28Rube_Goldberg_cartoon_with_caption%29.jpg • Glass Cockpit - https://upload.wikimedia.org/wikipedia/commons/9/9f/C-5M_Cockpit.jpg • Public Domain, https://commons.wikimedia.org/w/index.php?curid=2466026 • Stack of Papers - https://upload.wikimedia.org/wikipedia/commons/b/b6/FileStack_retouched.jpg • El Diablo - https://en.wikipedia.org/wiki/Fire_Ball#/media/File:El_Diablo_Roller_Coaster.jpg • Creative Commons license: https://creativecommons.org/licenses/by/2.0/