TDD by Controlling Dependencies
0 likes860 views
The document outlines TDD (Test-Driven Development) principles and methods, emphasizing the benefits of controlled dependencies, such as better code coverage and simpler design, alongside challenges like initial time investment. It discusses practical examples, including unit testing, UI testing, and the importance of mocking and stubbing in Swift. The author, Jorge D. Ortiz-Fuentes, highlights the balance between testing business logic and ensuring effective architecture through TDD strategies.
![Testing a use case
func testEntityIstransformedIntoDisplayData() {
entityGateway.entities = [Speaker(name: speakerMainName,
title: speakerMainTitle,
synopsis: speakerMainSynopsis,
dateSubmitted: speakerMainDateSubmitted)]
sut.showAllSpeakers()
guard presenter.displayData.count == entityGateway.entities.count
else { XCTFail(“There must be one and only one display data per each
entity of the repo.”)
return }
let speakerData = presenter.displayData[0]
XCTAssertEqual(speakerData.name, speakerMainName,
"Speaker name must be copied onto the display data.")
XCTAssertEqual(speakerData.title, speakerMainTitle,
"Speaker title must be copied onto the display data.")
XCTAssertEqual(speakerData.dateSubmitted, speakerMainDateSubmitted,
"Speaker submitedDate must be copied onto the display data.")
}](https://image.slidesharecdn.com/tddbycontrollingdependencies-151006152226-lva1-app6891/85/TDD-by-Controlling-Dependencies-32-320.jpg)
TDD by Controlling Dependencies
- 1. TDD by Controlling Dependencies Jorge D. Ortiz-Fuentes
- 3. You Go First
- 5. TDD by Controlling Dependencies Jorge D. Ortiz-Fuentes @jdortiz #Swift2TDD
- 7. #Swift2TDD Agenda ★ TDD ★ Real Life ★ Swift
- 8. TDD
- 9. TDD
- 10. #Swift2TDD Progress as a developer ★ It does things! ★ It does the things I want! ★ I can prove that it does what I say! ★ I am going to make it do exactly what i say! Nerdvana
- 11. #Swift2TDD The Rules of Testing ★ We only test our code ★ Only a level of abstraction ★ Only public methods ★ Only one assertion per test ★ Tests are independent of sequence or state
- 12. The TDD Dance
- 14. #Swift2TDD Pros ★ 100% coverage ★ Detect edge cases and unforeseen scenarios ★ Measurable progress ★ Easier to introduce changes ★ Less debug ★ Decoupled code ★ Explicit dependencies ★ Single responsibility ★ Autopilot programming ★ Simpler design Easier
- 15. TDD Cons?
- 16. #Swift2TDD Cons ★ Put the horse before the cart ★ Takes longer ★ Initial investment. Slower and more work in QA ★ Design without the big picture ★ Tests must also be rewritten when requirements change ★ Other tests are needed too ★ Tests are as bad as code
- 17. – Winston Churchill “Success is stumbling from failure to failure with no loss of enthusiasm.”
- 18. Real Life
- 19. UI Testing
- 20. Persistence
- 21. Traits
- 22. TDD Swift + 2
- 23. Test the UI
- 24. #Swift2TDD UI Testing ★ Xcode UI Testing ≠ Unit Testing ★ Nor is Kif, Calabash, or Cucumber (Integration) ★ Unit test is about isolation
- 25. View View Presenter Interactor EntityGateway
- 26. Make the view dumb class SpeakerTableViewCell: UITableViewCell { @IBOutlet weak var titleLabel: UILabel! @IBOutlet weak var nameLabel: UILabel! @IBOutlet weak var dateLabel: UILabel! } extension SpeakerTableViewCell: SpeakerCellProtocol { func displayName(name: String) { nameLabel.text = name } func displayTitle(title: String) { titleLabel.text = title } func displayDateSubmitted(date: String){ dateLabel.text = date } }
- 27. Testing a label func testDisplayDateChangesLabelTextToAltValue() { let labelMock = LabelMock() sut.dateLabel = labelMock sut.displayDateSubmitted(speakerAltDateSubmitted) XCTAssertTrue(labelMock.setTextWasInvoked, "displayDate must set the text of the label.") XCTAssertEqual(labelMock.text, speakerAltDateSubmitted, "displayDate must set the text of the label to the provided text.") } // MARK: - Stubs & Mocks class LabelMock: UILabel { // MARK: - Properties var setTextWasInvoked = false override var text: String? { didSet { setTextWasInvoked = true } } }
- 29. #Swift2TDD Testing Business Logic ★ Persistence seems to be a requirement for testing the logic ★ But it can be abstracted ★ And the data from the entity gateway
- 30. Clean Architecture View (VC) Presenter Connector Interactor Repository Persistence WSC
- 31. Isolate the user story class ShowAllSpeakersInteractor { // MARK: - Properties let entityGateway: EntityGatewayProtocol weak var presenter: SpeakersListPresenterProtocol? // MARK: - Initializers init(entityGateway: EntityGatewayProtocol) { self.entityGateway = entityGateway } } extension ShowAllSpeakersInteractor: ShowAllSpeakersInteractorProtocol { func showAllSpeakers() { let entities = entityGateway.fetchAllSpeakers() let displayData = entities.map({entity in return SpeakerDisplayData(speaker: entity)}) presenter?.presentAllSpeakers(displayData) } }
- 32. Testing a use case func testEntityIstransformedIntoDisplayData() { entityGateway.entities = [Speaker(name: speakerMainName, title: speakerMainTitle, synopsis: speakerMainSynopsis, dateSubmitted: speakerMainDateSubmitted)] sut.showAllSpeakers() guard presenter.displayData.count == entityGateway.entities.count else { XCTFail(“There must be one and only one display data per each entity of the repo.”) return } let speakerData = presenter.displayData[0] XCTAssertEqual(speakerData.name, speakerMainName, "Speaker name must be copied onto the display data.") XCTAssertEqual(speakerData.title, speakerMainTitle, "Speaker title must be copied onto the display data.") XCTAssertEqual(speakerData.dateSubmitted, speakerMainDateSubmitted, "Speaker submitedDate must be copied onto the display data.") }
- 33. Traits
- 34. Protocol extensions protocol SegueHandlerTypeProtocol { typealias SegueIdentifier: RawRepresentable } extension SegueHandlerTypeProtocol where Self: UIViewController, SegueIdentifier.RawValue == String { func performSegueWithIdentifier(segueIdentifier: SegueIdentifier, sender: AnyObject?) { performSegueWithIdentifier(segueIdentifier.rawValue, sender: sender) } func segueIdentifierForSegue(segue: UIStoryboardSegue) -> SegueIdentifier { guard let identifier = segue.identifier, segueIdentifier = SegueIdentifier(rawValue: identifier) else { fatalError("Invalid segue identifier (segue.identifier).") } return segueIdentifier } } As explained in WWDC 2015 Swift in Practice
- 35. Testing a Trait var sut: SegueHandlerTypeViewControlerMock! class SegueHandlerTypeViewControlerMock: UIViewController, SegueHandlerTypeProtocol { // MARK: - Properties var identifierToPerformSegue: String? var senderPerformingSegue: AnyObject? enum SegueIdentifier: String { case FirstSegue = "FirstSegueString" case SecondSegue = "SecondSegueString" } // MARK: - Mocks & Stubs override func performSegueWithIdentifier(identifier: String, sender: AnyObject?) { identifierToPerformSegue = identifier senderPerformingSegue = sender } }
- 36. Testing a trait (2) func testPerformSegueWithIdentifierInvokesClassicVersion() { sut.performSegueWithIdentifier(SegueHandlerTypeViewControlerMock.SegueIdentifier.FirstSeg ue, sender: nil) XCTAssertNotNil(sut.identifierToPerformSegue, "Classic version of performSegueWithIdentifier must be invoked by the one in the protocol extension.") } func testPerformSegueWithIdentifierPassesRawValueOfFirstIdentifier() { sut.performSegueWithIdentifier(SegueHandlerTypeViewControlerMock.SegueIdentifier.FirstSeg ue, sender: nil) XCTAssertEqual(sut.identifierToPerformSegue, firstSegueString, "Identifier must correspond to the raw value of the enum case.") } func testPerformSegueWithIdentifierPassesRawValueOfSecondIdentifier() { sut.performSegueWithIdentifier(SegueHandlerTypeViewControlerMock.SegueIdentifier.SecondSe gue, sender: nil) XCTAssertEqual(sut.identifierToPerformSegue, secondSegueString, "Identifier must correspond to the raw value of the enum case.") }
- 37. – Thomas A. Edison “I have not failed. I’ve just found 10,000 ways that won’t work.”
- 38. Thank you!