Domain Language throughout Tests, combining DDD and BDD

While software engineers are beginning to use the language of the domain (business language) more in their application code, in most tests we still see a lot of technical language. Especially when creating acceptance test for a GUI, we mostly go from gherkin to Selenium straight away! With the ever-growing culture of creating living documentation in the form of gherkin, it is evenly important to use the domain language in our test code too.

In this talk, I will explain how to combine Domain Driven Design (DDD) and Behaviour Driven Development (BDD). I will use Feature Mapping with Event Storming and Example Mapping so we can create a ubiquitous domain language that we can use in our application and test code. Using property-based testing and the Screenplay pattern, I will show several examples on how to use the domain language in test code. As a result, we have tests that are both useful for communication and serve as living documentation based on our domain language.

Transcript

1. Domain Language throughout Tests,
   combining DDD and BDD
   @kenny_baas
   Baasie.com
   

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3. ENFP PERSONALITY (“THE CAMPAIGNER”)
   

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4. Curious
   Imaginative and open-minded, seeing all things as part of a big, mysterious
   puzzle called life.
   Overthink Things
   They look for underlying motives in even
   the simplest things. It’s not uncommon for ENFPs to lose a bit of
   sleep asking themselves why someone did what they did,
   what it might mean, and what to do about it.
   ©https://www.16personalities.com/
   

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6. ©https://www.16personalities.com/
   

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8. 150 km
   50 km/h 50 km/h
   75 km/h
   

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9. … he solved it in an instant, and thereby disappointed the
   questioner: “Oh, you must have heard the trick before!” “What
   trick?” asked von Neumann, “All I did was sum the geometric
   series.”
   http://engineering.pivotal.io/post/abstraction-or-the-gift-of-our-weak-brains/
   

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10. 150 km
    50 km/h 50 km/h
    75 km/h
    1. you know the total time the fly is traveling (based on the trains’ relative speeds); (1:30 hour)
    2. and you’re given the fly’s speed.
    A simple velocity calculation later, and you have the answer. (75x1.5=112.5 km)
    

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11. electron behavior is actually so complicated,
    involving complex interactions between
    quantum probabilities, electromagnetic
    interactions, and macroscopic electric fields,
    that human brains are piteously underpowered
    to calculate what’s going on in an individual
    atom.
    http://engineering.pivotal.io/post/abstraction-or-the-gift-of-our-weak-brains/
    

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12. "Let us change our traditional attitude to the
    construction of programs: Instead of imagining
    that our main task is to instruct a computer what
    to do, let us concentrate rather on explaining
    to human beings what we want a computer
    to do"
    - Donald Knuth - Literate Programming
    “Programs must be written for people to read,
    and only incidentally for machines to execute.”
    - Hal Abelson
    http://engineering.pivotal.io/post/abstraction-or-the-gift-of-our-weak-brains/
    

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15. ©https://www.16personalities.com/
    

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18. ©https://www.16personalities.com/
    

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19. Feature: search Wikipedia
    Background:
    Given Open http://en.wikipedia.org
    And Do login
    Scenario: direct search article
    Given Enter search term 'Cucumber'
    When Do search
    Then Single result is shown for 'Cucumber'
    https://cucumber.io/blog/2014/03/03/the-worlds-most-misunderstood-collaboration-tool
    The world's most misunderstood collaboration tool
    

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20. Illustration by Paul Rayner (Thanks!)
    

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22. All your dreams are made
    When you're chained to the mirror and the razor blade
    Today's the day that all the world will see
    Another sunny afternoon
    Walking to the sound of my favorite tune
    Tomorrow never knows what it doesn't know
    too soon
    Need a little time to wake up
    Need a little time to wake up wake up
    Need a little time to wake up
    Need a little time to rest your mind
    You know you should so I guess you might
    as well
    What's the story morning glory?
    Well
    You need a little time to wake up wake up
    Well
    What's the story morning glory?
    

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23. All your dreams are made
    When you're chained to the mirror and the razor blade
    Today's the day that all the world will see
    Another sunny afternoon
    Walking to the sound of my favorite tune
    Tomorrow never knows what it doesn't know
    too soon
    Need a little time to wake up
    Need a little time to wake up wake up
    Need a little time to wake up
    Need a little time to rest your mind
    You know you should so I guess you might
    as well
    What's the story morning glory?
    Well
    You need a little time to wake up wake up
    Well
    What's the story morning glory?
    

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26. "Software Development is about
    learning, working code is a side
    effect"
    Alberto Brandolini @ziobrando
    

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32. ©https://www.16personalities.com/
    

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34. @Acceptance Testing for Continuous Delivery - Dave Farley
    

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35. @Acceptance Testing for Continuous Delivery - Dave Farley
    

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37. https://dddeurope.com/2017/speakers/romeu-moura/
    

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39. Navigation by public transport
    In order to know the fastest route between two places,
    As a commuter
    I want get to my destination as quickly as possible
    

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43. https://johnfergusonsmart.com/feature-mapping-a-simpler-path-from-stories-to-executable-acceptance-criteria/
    

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44. ● Commuter
    ● Trains
    

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45. http://eventstorming.com/
    

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47. Choose
    Origin
    Choose
    Destination
    Origin
    Selected
    Destination
    Selected
    

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48. https://cucumber.io/blog/2015/12/08/example-mapping-introduction
    

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52. http://serenity-js.org/design/screenplay-pattern.html
    

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55. #
    WRAPUP
    

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56. Empathy
    Story
    

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57. Questions?
    #CATTAX
    

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