Effortless Software Development

Software development can be an eternal struggle, or it can be code that pretty much writes itself. In this talk, we’ll look at how simple acceptance tests and a few diagrams help us dive right into the code, which we in turn outline using DDD, This allows us to have a clean and testable design without worrying about implementation details. Code can be then implemented without developers worrying about stepping on each others’ toes, while still be confident that everything will work once put together. Discover how my team can build features faster than the client can sign them off.

Transcript

1. 
   Effortless
   Software
   Development
   PHP RUSSIA | MAY 13, 2020
   @afilina
   

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2. Waiting for user tests
   Merge conflicts
   Adding missing requirements
   Waiting on someone else
   Someone you never heard of

   disagrees with requirements
   Redesign
   Despair
   Writing code
   Figuring out requirements
   50-page document
   Approving the document
   Figuring out...
   20 levels of inheritance
   800-line methods
   6 levels of nested IFs
   What does
   $array2 contain?
   How to unit-
   test this thing?
   Is this var null
   right now?
   

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3. Anna Filina
   ‣ Coding since 1997.
   ‣ PHP since 2003.
   ‣ Legacy archaeology.
   ‣ Test automation.
   ‣ Talks and workshops.
   ‣ YouTube videos.
   

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4. 1/3

   Better
   Specifications
   

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5. Getting an answer
   Dev
   Requirements User testing
   50-page

   document
   

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6. Question 2
   Missing use cases / redesign More testing
   er
   User testing
   

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7. Solution
   ‣ Get a product owner (not a committee).
   ‣ Direct & quick access to product owner.
   ‣ Should not have other roles in the org.
   ‣ Should not delegate questions.
   ‣ Communicate requirements using acceptance tests.
   

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8. Scenario: User can subscribe with a credit card
   Given I selected a membership option
   When I enter valid credit card details
   Then I should see a payment receipt
   

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9. Scenario: Discounts are matched based on current date
   Given A 5% discount "FIVE" active on 2019-01-01 through 2019-01-31
   And A 10% discount "TEN" active on 2019-02-01 through 2019-02-28
   And The current date is 2019-01-15
   When I check for discounts
   Then The "FIVE" discount should be found
   

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10. Requirements:

    collection of use cases

    that need to be accounted for.
    

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11. I select a
    membership option
    I enter valid credit
    card details
    I should see a
    payment receipt
    Requirements
    Use cases
    (scenarios)
    

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12. Scenario
    Dev
    Requirements User testing
    Use cases
    (scenarios)
    

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13. 2/3
    Iterative Design
    

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14. Design Dev
    Approval
    Mistake in 

    design
    

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15. The map is not the territory.

    — Alfred Korzybski
    

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16. Solution
    ‣ Sequence or activity diagram.
    ‣ Minimal code to validate design.
    

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17. API
    UI
    User
    Select membership
    Order
    Create order {product_code}
    Payment screen
    Enter payment details
    Receipt {confirmation_num}
    Finalize order {card}
    Receipt
    

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18. 3/3
    More Cooks

    in the Kitchen
    

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19. Solution
    ‣ Mob programming: validate the design.
    ‣ Split the work: implementation + tests.
    

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20. API
    UI
    User
    Select membership
    Order
    Create order {product_code}
    Payment screen
    Enter payment details
    Receipt {confirmation_num}
    Finalize order {card}
    Receipt
    

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21. final class CreateOrderHandler
    {
    public function handle(Request $request) : Response
    {
    $productCode = new ProductCode(
    $request->getAttribute('product_code')
    );
    $product = $this->products->getByCode($productCode);
    $order = $this->orders->create($product);
    return new JsonResponse([
    'order' => $order->toArray(),
    ]);
    }
    }
    

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22. public function __construct(
    ProductStorage $products,
    OrderStorage $orders
    )
    

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23. interface ProductStorage
    {
    public function getByCode(ProductCode $code) : Product;
    }
    interface OrderStorage
    {
    public function create(Product $product) : Order
    }
    

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24. final class ProductCode
    {
    private $code;
    public function __construct(string $code)
    {
    Assert::that($code)
    ->notBlank()
    ->maxLength(15);
    $this->code = $code;
    }
    public function getCode() : string
    {
    return $this->code;
    }
    }
    

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25. Mob Programming
    ‣ Handler: 13 lines.
    ‣ Interfaces: 8 lines.
    ‣ Value objects: 46 lines.
    ‣ = 67
    ‣ Shared vision.
    

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26. Split the Work
    ‣ Test handler.
    ‣ Implement interfaces + tests.
    ‣ Implement validation of value object + tests.
    ‣ Implement steps of acceptance tests.
    

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27. interface OrderStorage
    {
    public function create(Product $product, Country $country) : Order
    }
    

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28. Acceptance Tests
    ‣ Both for backend and frontend.
    ‣ Just for the backend.
    

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29. @wip
    Scenario: User can subscribe with a credit card
    Given I selected a membership option
    When I enter valid credit card details
    Then I should see a payment receipt
    Call 1
    Call 2
    Assertion
    

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30. Mission
    accomplished
    

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31. Lessons Learned
    ‣ Code is living documentation.
    ‣ Don't try to figure everything out upfront (unknowns).
    ‣ Mistakes are normal (fail fast).
    ‣ Work together more often.
    

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32. Further Topics
    ‣ Domain-driven design.
    ‣ Test-driven development.
    ‣ Behavior-driven development.
    ‣ SOLID principles.
    ‣ Clean code.
    ‣ Extreme programming.
    ‣ Scrum.
    

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33. 
    THANKS!
    @afilina
    @afilina
    

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