Ship 10 Times Faster With These Designs

Your competition will hate you. By the time they release one feature with a ton of bugs, you would have released 10 features with no bugs. A good design makes a world of difference in terms of ease of change, teamwork, testability, reliability and overall quality of life. I will present a software design approach that allowed my teams to ship unbelievably fast while keeping the quality above industry standards.

Transcript

1. Ship 10 Times Faster
   With These Designs
   CONFOO 2021 | FEB 25, 2021
   @afilina
   

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2. Anna Filina / @afilina
   • Coding since 1997.
   • PHP since 2003.
   • Legacy archaeology.
   • Test automation.
   • Talks and workshops.
   • YouTube videos.
   • Filina Consulting.
   

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3. Your competition will hate you. By the time they release one
   feature with a ton of bugs, you would have released 10
   features with no bugs. A good design makes a world of
   difference in terms of ease of change, teamwork, testability,
   reliability and overall quality of life. I will present a software
   design approach that allowed my teams to ship unbelievably
   fast while keeping the quality above industry standards.
   

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4. Waiting for all the information before starting work.
   

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5. Knowns
   • Payment Provider
   • Charge money
   • Refund money of a previous transaction
   

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6. Payment Provider
   charge
   

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7. Payment Provider
   charge (Money, Instrument)
   refund
   

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8. Payment Provider
   charge (Money, Instrument)
   refund (Money, PaymentId)
   

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9. Payment Provider
   charge (Money, Instrument) : PaymentId
   refund (Money, PaymentId)
   

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10. Payment Provider
    charge (Money, Instrument) : PaymentId
    refund (Money, PaymentId) : RefundId
    

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11. interface PaymentProvider
    {
    public function charge(Money $money, Instrument $instrument): PaymentId;
    }
    

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12. Are we able to use this interface?
    

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13. Submit
    Form field
    Form field
    POST
    /payments/capture
    

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14. Validate input
    Controller
    Charge via PaymentProvider
    Request Response
    Send output
    

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15. final class CapturePaymentHandler
    {
    public function handle(ServerRequestInterface $request): ResponseInterface
    {
    }
    }
    

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16. final class CapturePaymentHandler
    {
    public function handle(ServerRequestInterface $request): ResponseInterface
    {
    $paymentId = $this->paymentProvider->charge($money, $instrument);
    }
    }
    

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17. final class CapturePaymentHandler
    {
    public function handle(ServerRequestInterface $request): ResponseInterface
    {
    $money = Money::fromRequest($request);
    $instrument = Instrument::fromRequest($request);
    $paymentId = $this->paymentProvider->charge($money, $instrument);
    }
    }
    

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18. final class CapturePaymentHandler
    {
    public function handle(ServerRequestInterface $request): ResponseInterface
    {
    $money = Money::fromRequest($request);
    $instrument = Instrument::fromRequest($request);
    $paymentId = $this->paymentProvider->charge($money, $instrument);
    return $this->createSuccessResponse($paymentId);
    }
    }
    

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19. {
    "instrument": {
    //...
    },
    "money": {
    "currency": "USD",
    "amount": 1050
    }
    }
    {
    "paymentId": "CC-0001"
    }
    

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20. FE/BE Contract
    • Is input viable?
    • Is output viable?
    • Talk use cases.
    

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21. Waiting for all the information before starting work.
    Postpone decisions using interfaces.
    Write code for the things that you do know.
    Validate assumptions using code.
    Uncover new information or use cases.
    

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22. Can't have multiple developers on one feature.
    

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23. class CapturePaymentHandler
    {
    public function handle(ServerRequestInterface $request): ResponseInterface
    {
    $money = Money::fromRequest($request);
    $instrument = Instrument::fromRequest($request);
    $paymentId = $this->paymentProvider->charge($money, $instrument);
    return $this->createSuccessResponse($paymentId);
    }
    }
    

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24. class CapturePaymentHandler
    {
    public function handle(ServerRequestInterface $request): ResponseInterface
    {
    $money = Money::fromRequest($request);
    $instrument = Instrument::fromRequest($request);
    $paymentId = $this->paymentProvider->charge($money, $instrument);
    return $this->createSuccessResponse($paymentId);
    }
    }
    

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25. class CapturePaymentHandler
    {
    public function handle(ServerRequestInterface $request): ResponseInterface
    {
    $money = Money::fromRequest($request);
    $instrument = Instrument::fromRequest($request);
    $paymentId = $this->paymentProvider->charge($money, $instrument);
    return $this->createSuccessResponse($paymentId);
    }
    }
    

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26. interface PaymentProvider
    {
    /**
    * @throws ChargeFailed
    */
    public function charge(Money $money, Instrument $instrument): PaymentId;
    }
    

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27. $money = Money::fromRequest($request);
    $instrument = Instrument::fromRequest($request);
    try {
    $paymentId = $this->paymentProvider->charge($money, $instrument);
    } catch (ChargeFailed $exception) {
    return $this->createErrorResponse($exception->getMessage());
    }
    return $this->createSuccessResponse($paymentId);
    

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28. Handlers + tests
    PaymentProvider implementation + tests
    Acceptance tests + wiring components
    Value objects + tests
    POST
    /payments/capture
    

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29. Can't have multiple developers on one feature.
    Create separate classes with clear contracts.
    

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30. We don't understand the domain.
    

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31. charge($money, $instrument)
    Money
    int $amount
    string $currency
    charge(int $amount, string $currency, string $cardNumber,
    string $cardExpiry, string $postalCode, …)
    Instrument
    Card $card
    Address $address
    

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32. PaymentProvider
    HttpClient
    send (Request)
    charge (Money, Instrument)
    

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33. Money
    Instrument
    PaymentProvider
    Domain
    

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34. Money
    Instrument
    PaymentProvider
    CapturePaymentHandler Application
    

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35. Money
    Instrument
    PaymentProvider
    CapturePaymentHandler
    HttpClient Infrastructure
    

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36. Create Small Classes & Methods
    • 10 statements per method.
    • Classes that can fit in your head.
    

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37. We don't understand the domain.
    Separate the domain from the other layers.
    Create small classes and methods.
    

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38. Bugs.
    

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39. Money
    Instrument
    PaymentProvider
    CapturePaymentHandler
    HttpClient
    Unit tests
    Unit tests
    Integration tests
    Acceptance
    tests
    

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40. final class CapturePaymentHandler
    {
    private StripePaymentProvider $paymentProvider;
    public function __construct()
    {
    $this->paymentProvider = new StripePaymentProvider();
    }
    }
    

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41. final class CapturePaymentHandler
    {
    private PaymentProvider $paymentProvider;
    public function __construct(PaymentProvider $paymentProvider)
    {
    $this->paymentProvider = $paymentProvider;
    }
    }
    final class CapturePaymentHandler
    {
    private StripePaymentProvider $paymentProvider;
    public function __construct()
    {
    $this->paymentProvider = new StripePaymentProvider();
    }
    }
    

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42. final class CapturePaymentHandlerTest extends TestCase
    {
    protected function setUp(): void
    {
    $this->paymentProvider = $this->createMock(PaymentProvider::class);
    $this->capturePaymentHandler = new CapturePaymentHandler(
    $this->paymentProvider
    );
    }
    }
    

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43. Bugs.
    Just write tests.
    Learn to write even better tests.
    

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44. @afilina
    

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