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
   

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2. TDD Refresher
   Image by Industrial Logic Senior Consultant - Tim Ottinger
   @asciamanna
   anthonysciamanna.com
   

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3. @asciamanna
   anthonysciamanna.com
   TDD Refresher
   

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4. TDD Refresher
   @asciamanna
   anthonysciamanna.com
   

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5. TD Refresher
   Let’s go back in time!
   @asciamanna
   anthonysciamanna.com
   

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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
   

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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
   

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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
   

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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
   

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10. TDD Is a Testing Practice
    @asciamanna
    anthonysciamanna.com
    

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11. @asciamanna
    anthonysciamanna.com
    I don’t care if people write tests first or last.
    As long as they get written.
    - Anonymous Tech Lead
    

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12. @asciamanna
    anthonysciamanna.com
    Ignores Design and Workflow Benefits of TDD
    

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13. Benefits of TDD
    @asciamanna
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14. Benefits of TDD
    @asciamanna
    anthonysciamanna.com
    Externally Visible Artifacts
    Test Suite
    

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15. Benefits of TDD
    @asciamanna
    anthonysciamanna.com
    Externally Visible Artifacts
    Test Suite
    

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16. Benefits of TDD
    Externally Visible Artifacts
    @asciamanna
    anthonysciamanna.com
    Software
    Design
    Test Suite
    

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17. Benefits of TDD
    Externally Visible Artifacts
    @asciamanna
    anthonysciamanna.com
    Developer
    Workflow
    Software
    Design
    Test Suite
    

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18. Benefits of TDD
    Externally Visible Artifacts
    @asciamanna
    anthonysciamanna.com
    Developer
    Workflow
    Software
    Design
    Test Suite
    

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19. TDD Triple
    Balance
    anthonysciamanna.com
    Maker Making
    Made
    @asciamanna
    

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20. Benefits of TDD
    Externally Visible Artifacts
    anthonysciamanna.com
    Developer
    Workflow
    Software
    Design
    Test Suite
    @asciamanna
    

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21. Test Suite Benefits
    Why we prefer TDD-style tests over Test After Tests
    

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22. Test Suite
    Quality
    Production
    Code
    Quality
    Test suite quality influences production
    code quality and vice-versa
    @asciamanna
    anthonysciamanna.com
    

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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
    

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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
    

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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
    

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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
    

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27. S
    O
    S
    anthonysciamanna.com @asciamanna
    

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28. Small
    O
    S
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29. Small
    Obvious
    S
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30. Small
    Obvious
    Simple
    anthonysciamanna.com
    @asciamanna
    

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31. Small
    ~12 LOC or less per test
    @asciamanna
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32. Obvious
    anthonysciamanna.com
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33. Arrange
    Act
    Assert
    Arrange – Act – Assert
    Or
    Given - When - Then
    anthonysciamanna.com @asciamanna
    

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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
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35. Simple
    Avoid branching
    and flow control
    logic in tests
    anthonysciamanna.com @asciamanna
    

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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
    

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37. How To Stop Hating Your Test Suite
    Test code is untested code!
    - Justin Searls, Co-founder Test Double
    anthonysciamanna.com @asciamanna
    

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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.
    

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39. Software Design Benefits
    Tests guiding quality software design
    

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40. TDD Disclaimer
    TDD influences design quality
    But it’s not a magic wand!
    anthonysciamanna.com @asciamanna
    

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41. TDD Disclaimer
    TDD influences design quality
    High Cohesion Loose Coupling
    Small Classes Small Methods
    anthonysciamanna.com @asciamanna
    

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42. TDD Disclaimer
    TDD provides a mechanism
    for learning software design
    High Cohesion Loose Coupling
    Small Classes Small Methods
    anthonysciamanna.com @asciamanna
    

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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
    

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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
    

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45. Microtests are litmus tests
    for software design quality
    @asciamanna
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46. Examples
    @asciamanna
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47. Too Much Test Setup
    Too Many Dependencies Too Many Arguments
    Arguments are Too Complex Code Under Test Doing Too Much
    anthonysciamanna.com @asciamanna
    

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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
    

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49. Too Many Asserts
    Returning too complex of a type
    Code under test doing too much
    anthonysciamanna.com @asciamanna
    

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50. Too Many Test Cases
    Too much branching logic
    Code under test is
    doing too much
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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
    

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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
    

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53. Developer Workflow Benefits
    Short, fast feedback cycles improve productivity
    

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54. Nearly instantaneous
    feedback loops
    anthonysciamanna.com @asciamanna
    

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55. Fast Feedback Loops
    key to developer
    productivity & high
    performing teams
    anthonysciamanna.com @asciamanna
    

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56. anthonysciamanna.com @asciamanna
    

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57. Resilient to Interruptions
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58. TDD-created Microtests are save states for system functionality
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59. anthonysciamanna.com @asciamanna
    

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60. BIG PROBLEM
    @asciamanna
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61. BIG PROBLEM
    @asciamanna
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    Great software is created by GREAT TEAMS not heroic, rockstar, 10X
    developers working in isolation
    

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62. BIG PROBLEM
    @asciamanna
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    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
    

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63. System is always in a working state
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64. Tiny Validations
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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
    

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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
    

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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
    

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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
    

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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
    

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70. Mental Benefits of TDD
    Concrete and visible progress on small incremental goals
    @asciamanna
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71. Mental Benefits of TDD
    @asciamanna
    anthonysciamanna.com
    Achieving Profluence
    

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72. Mental Benefits of TDD
    Little or no time spent in the
    debugger or on repetitive,
    time consuming manual
    checks
    anthonysciamanna.com @asciamanna
    

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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
    

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74. http://bit.ly/beyond-unit-testing-2021
    @asciamanna
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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/
    

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