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

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?

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

1/3
 Better Specifications

Getting an answer Dev Requirements User testing 50-page
 document

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

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.

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

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

Requirements:
 collection of use cases
 that need to be accounted for.

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

Scenario Dev Requirements User testing Use cases (scenarios)

2/3 Iterative Design

Design Dev Approval Mistake in 
 design

The map is not the territory.
 — Alfred Korzybski

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

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

3/3 More Cooks
 in the Kitchen

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

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

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(), ]); } }

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

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

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; } }

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

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

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

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

@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

Mission accomplished

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

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

THANKS! @afilina @afilina