TDD, DDD & Teamwork v2

#wczg

Transcript

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2. TDD,
   DDD
   & Teamwork
   pelshoff.com/workshop
   @pelshoff #wczg
   

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3. Part I: TDD
   

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4. What is a test?
   

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5. Something
   shouldn’t happen
   ● Expect exception
   ● Do the thing
   

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6. final class PresentationTest extends TestCase
   {
   /**
   * @test
   */
   public function presentationsShouldHaveTitles(): void
   {
   $this->expectException(InvalidPresentation::class);
   new Presentation('', '', '');
   }
   }
   

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7. Something should
   happen
   ● Do the thing
   ● Expect result
   

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8. final class PresentationTest extends TestCase
   {
   /**
   * @test
   */
   public function presentationsShouldAllowNewSubtitles(): void
   {
   $actual = new Presentation('With', 'a', 'title');
   $expectation = new Presentation('With', 'another', 'title');
   $actual->changeSubtitleTo('another');
   $this->assertEquals($expectation, $actual);
   }
   }
   

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9. What is a good test?
   

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10. A good test...
    ● Arrange
    ● Act
    ● Assert
    

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11. A good test...
    ● Setup
    ● Expect
    ● Execute
    ● Verify
    

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12. A good test...
    ● Setup
    ● Expect
    ● Perform
    ● Assert
    

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13. A good test...
    ● Given
    ● When
    ● Then
    

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14. What is TDD?
    

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15. “Test-Driven Development (TDD) is a
    technique for building software that guides
    software development by writing tests.” -
    Martin Fowler
    

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16. Three steps of
    TDD
    ● Red
    ● Green
    ● Refactor
    

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17. What is the difference between
    test-first & TDD?
    

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18. Recap
    ● Given, When, Then
    ● Red, Green, Refactor
    ● Client-first
    

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19. Good luck and have fun!
    

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20. Part II: Teamwork
    

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21. The Attitude Model
    

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22. Divergent
    

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23. Convergent
    

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24. Divergent
    Tend to be…
    ● Open
    ● Optimistic and curious
    ● Quick, sloppy and careless
    

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25. Convergent
    Tend to be...
    ● Closed
    ● Pessimistic and inquisitive
    ● Paced, diligent and careful
    

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26. The Double Design Diamond
    

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28. Good luck and have fun!
    

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29. Part III: DDD
    

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30. Value objects
    

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31. final class Name {
    private $lastName;
    private $firstName;
    private $insertion;
    public function __construct(string $lastName, string $firstName, string $insertion) {
    $this->lastName = $lastName;
    $this->firstName = $firstName;
    $this->insertion = $insertion;
    $this->nameMustHaveLastName();
    }
    private function nameMustHaveLastName(): void {
    if (!$this->lastName) {
    throw InvalidName::becauseLastNameIsMissing();
    }
    }
    public function getLastName(): string { /**/ }
    public function getFirstName(): string { /**/ }
    public function getInsertion(): string { /**/ }
    }
    

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32. final class EmailAddress {
    private $emailAddress;
    public function __construct(string $emailAddress) {
    $this->emailAddress = $emailAddress;
    $this->emailAddressMustBeAnActualEmailAddress();
    }
    private function emailAddressMustBeAnActualEmailAddress(): void {
    if (!filter_var($this->emailAddress, FILTER_VALIDATE_EMAIL)) {
    throw InvalidEmailAddress::becauseThisIsNotAnEmailAddress();
    }
    }
    public function asString(): string {
    return $this->emailAddress;
    }
    }
    

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33. Value objects
    ● Express a value
    ● Define allowed values
    ● Are immutable
    ● Are easy to test
    

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34. Entities
    

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35. final class Attendee {
    private $id;
    private $name;
    private $emailAddress;
    public function __construct(Uuid $id, Name $name, EmailAddress $emailAddress) {
    $this->id = $id;
    $this->name = $name;
    $this->emailAddress = $emailAddress;
    }
    public function getId(): Uuid { /**/ }
    public function getName(): Name { /**/ }
    public function setName(Name $name): Attendee { /**/ }
    public function getEmailAddress(): EmailAddress { /**/ }
    public function setEmailAddress(EmailAddress $emailAddress): Attendee {
    $this->emailAddress = $emailAddress;
    return $this;
    }
    }
    

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36. Entities
    ● Have identity
    ● Are more than their attributes
    ● Evolve over time
    ● Are slightly harder to test
    

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37. Services
    

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38. final class Registration {
    private $repository;
    public function __construct(AttendeeRepository $repository) {
    $this->repository = $repository;
    }
    public function registerNew(Attendee $attendee): void {
    $this->emailAddressMustBeUnique($attendee->getEmailAddress());
    $this->repository->add($attendee);
    }
    private function emailAddressMustBeUnique(EmailAddress $emailAddress): void {
    try {
    $this->repository->findByEmailAddress($emailAddress);
    } catch (AttendeeNotFound $e) {
    return;
    }
    throw RegistrationFailed::becauseEmailAddressIsNotUnique();
    }
    }
    

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39. Services
    ● Have no identity or attributes
    (Are not a “thing”)
    ● Tackle cross-concern operations
    ● Are harder to test
    

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40. Context
    Technische bouwblokken
    Quiz
    Case study I
    Case study II
    

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41. class Address
    

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42. class BicycleService
    

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43. class StreetAddress
    

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44. class Investment
    

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45. Good luck and have fun!
    

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46. Pim Elshoff
    developer.procurios.com
    @pelshoff #wczg
    https://joind.in/event/webcamp-zagreb-2019/tdd-ddd--teamwork
    

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