Venturing into the world of RxSwift unit testing

Reactive programming is an emerging discipline that allows to write declarative, asynchronous and concurrent code in a functional way and is continuously gaining popularity and adoption.

In this talk we will wander in the unexplored pathways of RxSwift testing infrastructure. Specifically, we will look into the key aspects of testing RxSwift code and we will analyze the different ways to unit test observable streams through a simple sign in app.

Presented in MobileOptimized in Minsk in 2019:
https://www.youtube.com/watch?v=49K6MMhn-fc

Presented in NSSpain in Logrono, Spain in 2019:
https://vimeo.com/362134004?fbclid=IwAR04dN8rRMFIVkR-7bEUY3R_9uEkq8WN_A13Kj1E_C9Fa8TFpcXqPjCXVDI

Presented in 360iDev in Denver, Co, USA in 2019:
https://vimeo.com/365321297

Transcript

1. @elenipapanikolo Venturing into the world of RxSwift unit testing Eleni Papanikolopoulou iOS Developer @Workable
2. Agenda RxSwift Basic Concepts Sign In app implemented with RxSwift Different ways of unit testing the app
3. RxSwift ReactiveX for Swift Reactive Programming
4. Basic Concepts
5. 1. Observables Sequence emits elements asynchronously subscribe receive sequence elements aka events❓
6. enum Event<Element> { case next(Element) // next element of a sequence case error(Swift.Error) // sequence failed with error case completed // sequence terminated successfully } 2. Events error next completed
7. 3. Observers Closure that is passed to the Observable in order to receive the sequence elements Listen for the events subsribe
8. 4. Subjects PublishSubject ReplaySubject BehaviourSubject Variable
9. PublishSubject ReplaySubject BehaviourSubject Variable 4. Subjects
10. 5. Operators Transform, combine or filter the events emitted map flatMap combineLatest filter merge startWith withLatestFrom skip take skipUntil takeUntil zip just catchError distinctUntilChanged sample takeLast scan concat startWith switchLatest skipWhile takeWhile takeWhileWithIndex empty never throw retry debounce ignoreElements sample throttle of single reduce flatMapFirst flatMapLatest RxMarbles ✅
11. 6. Side effects do(onNext) do(onCompleted) do(onError) doOn
12. 7. Schedulers ⏰ ✅ to force operators do their work on a specific queue MainScheduler SerialDispatchQueueScheduler CurrentThreadScheduler ConcurrentDispatchQueueScheduler OperationQueueScheduler
13. 8. DisposeBag Cancel Subscription
15. A simple Sign in App
16. Architecture View Controller View Model Events Observables MVVM
17. View Model
18. View Model Observable< > Observable< > Observable< > Observable< > Observable< > Observable< > Observable< > Inputs Outputs
19. The View Model class SignInViewModel { }
20. The View Model class SignInViewModel { //input var emailText: Observable<String>! var passwordText: Observable<String>! var signInButtonTap: Observable<Void>!
21. The View Model class SignInViewModel { //input var emailText: Observable<String>! var passwordText: Observable<String>! var signInButtonTap: Observable<Void>! //output var emailIsValid: Observable<Bool>! var passwordIsValid: Observable<Bool>! var signInButtonEnabled: Observable<Bool>! var signIn: Observable<SignInResponse>!
22. The View Model class SignInViewModel { //input var emailText: Observable<String>! var passwordText: Observable<String>! var signInButtonTap: Observable<Void>! //output var emailIsValid: Observable<Bool>! var passwordIsValid: Observable<Bool>! var signInButtonEnabled: Observable<Bool>! var signIn: Observable<SignInResponse>! init(signInAPI: SignInAPIType, disposeBag: DisposeBag) { self.signInAPI = signInAPI self.disposeBag = disposeBag } }
23. Configuring the view model //input func configure(emailText: Observable<String>, passwordText: Observable<String>, signInButtonTap: Observable<Void>) { }
24. / // Email let emailRegexMatcher = RegexMatcher(regex: ““email_regex””) emailIsValid = emailText.map({ return emailRegexMatcher.matches(string: $0) }) Observable< String > Observable< Bool > map } Configuring the view model //input func configure(emailText: Observable<String>, passwordText: Observable<String>, signInButtonTap: Observable<Void>) { }
25. Configuring the view model //input func configure(emailText: Observable<String>, passwordText: Observable<String>, signInButtonTap: Observable<Void>) { // Email let emailRegexMatcher = RegexMatcher(regex: "email_regex") emailIsValid = emailText.map({ return emailRegexMatcher.matches(string: $0)}) // Password let passwordRegexMatcher = RegexMatcher(regex: “password_regex”) passwordIsValid = passwordText.map({ return passwordRegexMatcher.matches(string:$0)}) }
26. Configuring the view model //input func configure(emailText: Observable<String>, passwordText: Observable<String>, signInButtonTap: Observable<Void>) { // Email let emailRegexMatcher = RegexMatcher(regex: "email_regex") emailIsValid = emailText.map({ return emailRegexMatcher.matches(string: $0)}) // Password let passwordRegexMatcher = RegexMatcher(regex: “password_regex”) passwordIsValid = passwordText.map({ return passwordRegexMatcher.matches(string:$0)}) } // SignIn Button signInButtonEnabled = Observable.combineLatest(emailIsValid, passwordIsValid { (emailIsValid, passwordIsValid) -> Bool in return emailIsValid && passwordIsValid }.startWith(false)
27. Configuring the view model //input func configure(emailText: Observable<String>, passwordText: Observable<String>, signInButtonTap: Observable<Void>) { // Email let emailRegexMatcher = RegexMatcher(regex: "email_regex") emailIsValid = emailText.map({ return emailRegexMatcher.matches(string: $0)}) // Password let passwordRegexMatcher = RegexMatcher(regex: “password_regex”) passwordIsValid = passwordText.map({ return passwordRegexMatcher.matches(string:$0)}) } // Sign In Action signIn = Observable.combineLatest(emailText, emailIsValid, passwordText, passwordIsValid, signInButtonTap, resultSelector: { (emailText, emailIsValid, passwordText, passwordIsValid, signInTap) -> SignInDetails? in guard emailIsValid, passwordIsValid else { return nil } return SignInDetails(emailText: emailText, passwordText: passwordText) }) .unwrap() .flatMapLatest({[weak self](signUpDetails) -> Observable<SignInResponse> in guard let strongSelf = self else { return .empty() } return strongSelf.signInAPI.signIn(with: signUpDetails) }) } // SignIn Button signInButtonEnabled = Observable.combineLatest(emailIsValid, passwordIsValid { (emailIsValid, passwordIsValid) -> Bool in return emailIsValid && passwordIsValid }.startWith(false)
28. // Sign In Action signIn = Observable.combineLatest(emailText, emailIsValid, passwordText, passwordIsValid, signInButtonTap, resultSelector: { (emailText, emailIsValid, passwordText, passwordIsValid, signInTap) -> SignInDetails? in guard emailIsValid, passwordIsValid else { return nil } return SignInDetails(emailText: emailText, passwordText: passwordText) }) .unwrap() .flatMapLatest({[weak self](signUpDetails) -> Observable<SignInResponse> in guard let strongSelf = self else { return .empty() } return strongSelf.signInAPI.signIn(with: signUpDetails) }) }
29. .unwrap() -> import RxSwiftExt .combineLatest() .flatMapLatest() /* Takes a sequence of optional elements and returns a sequence of non-optional elements, filtering out any nil values. - returns: An observable sequence of non-optional elements */
30. RxMagic… // Sign In Action signIn = Observable.combineLatest(emailText, emailIsValid, passwordText, passwordIsValid, signInButtonTap, resultSelector: { (emailText, emailIsValid, passwordText, passwordIsValid, signInTap) -> SignInDetails? in guard emailIsValid, passwordIsValid else { return nil } return SignInDetails(emailText: emailText, passwordText: passwordText) }) .unwrap() .flatMapLatest({[weak self](signUpDetails) -> Observable<SignInResponse> in guard let strongSelf = self else { return .empty() } return strongSelf.signInAPI.signIn(with: signUpDetails) }) }
31. protocol SignInAPIType { func signIn(with signInDetails: SignInDetails) -> Observable<SignInResponse> } struct SignInResponse: Decodable { let token: String } The Sign In API class SignInAPI: SignInAPIType { let httpClient: HttpClient = HttpClient.sharedService func signIn(with signInDetails: SignInDetails) -> Observable<SignInResponse> { let parameters: [String: Any] = ["email:" : signInDetails.emailText, "password": signInDetails.passwordText] return httpClient.loadRequestWithPath("/backend/api/signin", parameters: parameters, method: .POST, headers: []) } }
32. The Sign In View Controller class SignInViewController: UIViewController { @IBOutlet weak var emailTextfield: UITextField! @IBOutlet weak var passwordTextField: UITextField! @IBOutlet weak var signInButton: UIButton! @IBOutlet weak var emailErrorLabel: UILabel! @IBOutlet weak var passwordErrorLabel: UILabel! }
33. The Sign In View Controller class SignInViewController: UIViewController { @IBOutlet weak var emailTextfield: UITextField! @IBOutlet weak var passwordTextField: UITextField! @IBOutlet weak var signInButton: UIButton! @IBOutlet weak var emailErrorLabel: UILabel! @IBOutlet weak var passwordErrorLabel: UILabel! private let disposeBag = DisposeBag() private var viewModel: SignInViewModel! override func viewDidLoad() { super.viewDidLoad() viewModel = SignInViewModel(signInAPI: SignInAPI(), disposeBag: disposeBag) } }
34. The Sign In View Controller class SignInViewController: UIViewController { @IBOutlet weak var emailTextfield: UITextField! @IBOutlet weak var passwordTextField: UITextField! @IBOutlet weak var signInButton: UIButton! @IBOutlet weak var emailErrorLabel: UILabel! @IBOutlet weak var passwordErrorLabel: UILabel! private let disposeBag = DisposeBag() private var viewModel: SignInViewModel! override func viewDidLoad() { super.viewDidLoad() viewModel = SignInViewModel(signInAPI: SignInAPI(), disposeBag: disposeBag) } } let email = emailTextfield.rx.text.asObservable().filter({ $0.isEmpty }) viewModel.configure(emailText: email,
35. The Sign In View Controller } let email = emailTextfield.rx.text.asObservable().filter({ $0.isEmpty }) viewModel.configure(emailText: email, override func viewDidLoad() { super.viewDidLoad() viewModel = SignInViewModel(signInAPI: SignInAPI(), disposeBag: disposeBag) let password = passwordTextField.rx.text.asObservable().filter({ !$0.isEmpty }) let signInButtonTap = signInButton.rx.tap.asObservable() passwordText: password, signInButtonTap: signInButtonTap)
36. //subsribe to the outputs viewModel.emailIsValid.bind(to: emailErrorLabel.rx.isHidden).disposed(by: disposeBag) override func viewDidLoad() { super.viewDidLoad() viewModel = SignInViewModel(signInAPI: SignInAPI(), disposeBag: disposeBag) let email = emailTextfield.rx.text.asObservable().filter({ !$0.isEmpty }) let password = passwordTextField.rx.text.asObservable().filter({ !$0.isEmpty }) let signInButtonTap = signInButton.rx.tap.asObservable() viewModel.configure(emailText: email, passwordText: password, signInButtonTap: signInButtonTap) }
37. override func viewDidLoad() { super.viewDidLoad() viewModel = SignInViewModel(signInAPI: SignInAPI(), disposeBag: disposeBag) let email = emailTextfield.rx.text.asObservable().filter({ !$0.isEmpty }) let password = passwordTextField.rx.text.asObservable().filter({!$0.isEmpty }) let signInButtonTap = signInButton.rx.tap.asObservable() viewModel.configure(emailText: email, passwordText: password, signInButtonTap: signInButtonTap) //subsribe to the outputs viewModel.emailIsValid.bind(to: emailErrorLabel.rx.isHidden).disposed(by: disposeBag) viewModel.passwordIsValid.bind(to: passwordErrorLabel.rx.isHidden).disposed(by: disposeBag) viewModel.signInButtonEnabled.bind(to: signInButton.rx.isEnabled).disposed(by: disposeBag) }
38. override func viewDidLoad() { super.viewDidLoad() viewModel = SignInViewModel(signInAPI: SignInAPI(), disposeBag: disposeBag) let email = emailTextfield.rx.text.asObservable().filter({ !$0.isEmpty }) let password = passwordTextField.rx.text.asObservable().filter({!$0.isEmpty }) let signInButtonTap = signInButton.rx.tap.asObservable() viewModel.configure(emailText: email, passwordText: password, signInButtonTap: signInButtonTap) //subsribe to the outputs viewModel.emailIsValid.bind(to: emailErrorLabel.rx.isHidden).disposed(by: disposeBag) viewModel.passwordIsValid.bind(to: passwordErrorLabel.rx.isHidden).disposed(by: disposeBag) viewModel.signInButtonEnabled.bind(to: signInButton.rx.isEnabled).disposed(by: disposeBag) viewModel.signIn .observeOn(MainScheduler.instance) .subscribe( onNext: { [weak self] (response) in self?.showAlert(for: response) }, onError: { [weak self] error in self?.showAlert(for: error) } ).disposed(by: disposeBag) }
39. Start writing the unit tests
40. Architecture View Controller View Model Events Observables fake verify
41. Quick/Nimble Quick is a behavior-driven development (BDD) framework to write tests as specs in simple structures.
42. Quick/Nimble Quick is a behavior-driven development (BDD) framework to write tests as specs in simple structures. Nimble is a matcher framework that is expressive and supports asynchronous tests.
43. Quick/Nimble Quick is a behavior-driven development (BDD) framework to write tests as specs in simple structures. Nimble is a matcher framework that is expressive and supports asynchronous tests. With Quick and Nimble, each test is written in as an it closure, and each expectation is expressed as:
44. Quick/Nimble ☑ Expectation: expect(something).to(condition) or expect(something).toNot(condition) Quick is a behavior-driven development (BDD) framework to write tests as specs in simple structures. Nimble is a matcher framework that is expressive and supports asynchronous tests. With Quick and Nimble, each test is written in as an it closure, and each expectation is expressed as:
45. Quick/Nimble override func spec() { describe("The Subject Under Test") { beforeEach { // initialization code } context("when a condition applies") { beforeEach { // condition initialization code } it("expectation description”) { // expectation - assertion } } } }
46. What to test? The SignInViewModel
47. class SignInAPIFake: SignInAPIType { } Mock the network layer
48. class SignInAPIFake: SignInAPIType { var signInCalled = false var signInReturnValue: PublishSubject<SignInResponse>! func signIn(with signInDetails: SignInDetails) -> Observable<SignInResponse> { signInReturnValue = PublishSubject() return signInReturnValue.asObservable() .do(onSubscribe: {[weak self] in self?.signInCalled = true }) } } Mock the network layer
49. Different ways Set the timeline of events
50. Different ways Set the timeline of events ☑ by using PublishSubject
51. Different ways Set the timeline of events ☑ by using RxBlocking ☑ by using PublishSubject
52. Different ways Set the timeline of events ☑ by using RxBlocking ☑ by using TestScheduler ☑ by using PublishSubject
53. Different ways Set the timeline of events ☑ by using RxBlocking ☑ by using Marble Syntax ☑ by using TestScheduler ☑ by using PublishSubject
54. Different ways Set the timeline of events ☑ by using RxBlocking ☑ by using Marble Syntax ☑ by using TestScheduler ☑ by using PublishSubject
55. class SignInViewModelPublishSubjectSpec: QuickSpec { override func spec() { describe("The SignInViewModel") { } } }
56. class SignInViewModelPublishSubjectSpec: QuickSpec { override func spec() { describe("The SignInViewModel") { var sut: SignInViewModel!
57. class SignInViewModelPublishSubjectSpec: QuickSpec { override func spec() { describe("The SignInViewModel") { var sut: SignInViewModel! var signInAPI: SignInAPIFake! var disposeBag: DisposeBag!
58. class SignInViewModelPublishSubjectSpec: QuickSpec { override func spec() { describe("The SignInViewModel") { var sut: SignInViewModel! var signInAPI: SignInAPIFake! var disposeBag: DisposeBag! // Fake the events var emailText: PublishSubject<String>! var passwordText: PublishSubject<String>! var signInButtonTap: PublishSubject<Void>!
59. class SignInViewModelPublishSubjectSpec: QuickSpec { override func spec() { describe("The SignInViewModel") { var sut: SignInViewModel! var signInAPI: SignInAPIFake! var disposeBag: DisposeBag! // Fake the events var emailText: PublishSubject<String>! var passwordText: PublishSubject<String>! var signInButtonTap: PublishSubject<Void>! // Results var emailIsValid: Bool! var passwordIsValid: Bool! var signInButtonEnabled: Bool! var signInResponse: SignInResponse! } } }
60. beforeEach { }
61. beforeEach { signInAPI = SignInAPIFake() disposeBag = DisposeBag()
62. beforeEach { signInAPI = SignInAPIFake() disposeBag = DisposeBag() sut = SignInViewModel(signInAPI: signInAPI, disposeBag: disposeBag)
63. beforeEach { signInAPI = SignInAPIFake() disposeBag = DisposeBag() sut = SignInViewModel(signInAPI: signInAPI, disposeBag: disposeBag) emailText = PublishSubject<String>() passwordText = PublishSubject<String>() signInButtonTap = PublishSubject<Void>()
64. beforeEach { signInAPI = SignInAPIFake() disposeBag = DisposeBag() sut = SignInViewModel(signInAPI: signInAPI, disposeBag: disposeBag) emailText = PublishSubject<String>() passwordText = PublishSubject<String>() signInButtonTap = PublishSubject<Void>() // Fake the inputs sut.configure(emailText: emailText, passwordText: passwordText, signInButtonTap: signInButtonTap) }
65. sut.passwordIsValid.subscribe(onNext: { (isValid) in passwordIsValid = isValid }).disposed(by: disposeBag) sut.signInButtonEnabled.subscribe(onNext: { (enabled) in signInButtonEnabled = enabled }).disposed(by: disposeBag) sut.signIn.subscribe(onNext: { (response) in signInResponse = response }).disposed(by: disposeBag) beforeEach { // “Listen” the events sut.emailIsValid.subscribe(onNext: { (isValid) in emailIsValid = isValid }).disposed(by: disposeBag) }
66. it("should get an initial event that sign in should not be enabled") { expect(signInButtonEnabled).to(beFalse()) }
67. it("should get an initial event that sign in should not be enabled") { expect(signInButtonEnabled).to(beFalse()) } context("when an invalid email is typed") { beforeEach { emailText.on(.next("test@")) } }
68. it("should get an initial event that sign in should not be enabled") { expect(signInButtonEnabled).to(beFalse()) } context("when an invalid email is typed") { beforeEach { emailText.on(.next("test@")) } it("should get an event that email is invalid") { expect(emailIsValid).to(beFalse()) } }
69. it("should get an initial event that sign in should not be enabled") { expect(signInButtonEnabled).to(beFalse()) } context("when an invalid email is typed") { beforeEach { emailText.on(.next("test@")) } it("should get an event that email is invalid") { expect(emailIsValid).to(beFalse()) } context("when an invalid password is typed") { beforeEach { passwordText.on(.next("asd")) } } }
70. it("should get an initial event that sign in should not be enabled") { expect(signInButtonEnabled).to(beFalse()) } context("when an invalid email is typed") { beforeEach { emailText.on(.next("test@")) } it("should get an event that email is invalid") { expect(emailIsValid).to(beFalse()) } context("when an invalid password is typed") { beforeEach { passwordText.on(.next("asd")) } it("should get an event that password is invalid") { expect(passwordIsValid).to(beFalse()) } } }
71. it("should get an initial event that sign in should not be enabled") { expect(signInButtonEnabled).to(beFalse()) } context("when an invalid email is typed") { beforeEach { emailText.on(.next("test@")) } it("should get an event that email is invalid") { expect(emailIsValid).to(beFalse()) } context("when an invalid password is typed") { beforeEach { passwordText.on(.next("asd")) } it("should get an event that password is invalid") { expect(passwordIsValid).to(beFalse()) } it("should get another event that sign in button should not be enabled") { expect(signInButtonEnabled).to(beFalse()) } } }
72. context("when valid email and password are typed") { beforeEach { emailText.on(.next(“test@gmail.com”)) passwordText.on(.next("Asd123!!")) } }
73. context("when valid email and password are typed") { beforeEach { emailText.on(.next(“test@gmail.com”)) passwordText.on(.next("Asd123!!")) } it("should get an event that email is valid") { expect(emailIsValid).to(beTrue()) } it("should get an event that password is valid") { expect(passwordIsValid).to(beTrue()) } it("should get an event that sign in button should be enabled") { expect(signInButtonEnabled).to(beTrue()) } }
74. context("when sign in button is tapped") { beforeEach { signInButtonTap.on(.next(())) } }
75. context("when sign in button is tapped") { beforeEach { signInButtonTap.on(.next(())) } it("a sign in request should be made") { expect(signInAPI.signInCalled).to(beTrue()) } }
76. context("when sign in button is tapped") { beforeEach { signInButtonTap.on(.next(())) } it("a sign in request should be made") { expect(signInAPI.signInCalled).to(beTrue()) } context("when sign in response arrives") { beforeEach { let signInResponse = SignInResponse(token: "fake_token") signInAPI.signInReturnValue.on(.next(signInResponse)) } } }
77. context("when sign in button is tapped") { beforeEach { signInButtonTap.on(.next(())) } it("a sign in request should be made") { expect(signInAPI.signInCalled).to(beTrue()) } context("when sign in response arrives") { beforeEach { let signInResponse = SignInResponse(token: "fake_token") signInAPI.signInReturnValue.on(.next(signInResponse)) } it("should give an event with the correct sign in response") { expect(signInResponse.token).to(equal("fake_token")) } } }
78. Done
79. class SignInViewModelPublishSubjectSpec: QuickSpec { override func spec() { describe("The SignInViewModel") { beforeEach { //initialization } it("should get an initial event that sign in should not be enabled") { expect(signInButtonEnabled).to(beFalse()) } context("when an invalid email is typed") { beforeEach { emailText.on(.next("test@")) } it("should get an event that email is invalid") { expect(emailIsValid).to(beFalse()) } context("when an invalid password is typed") { beforeEach { passwordText.on(.next("asd")) } it("should get an event that password is invalid") { expect(passwordIsValid).to(beFalse()) } it("should get another event that sign in button should not be enabled") { expect(signInButtonEnabled).to(beFalse()) } context("when valid email and password are typed") { beforeEach { emailText.on(.next("test@gmail.com")) passwordText.on(.next("Asd123!!")) } it("should get an event that email is valid") { expect(emailIsValid).to(beTrue()) } it("should get an event that password is valid") { expect(passwordIsValid).to(beTrue()) } it("should get an event that sign in button should be enabled") { expect(signInButtonEnabled).to(beTrue()) } context("when sign in button is tapped") { beforeEach { signInButtonTap.on(.next(())) } it("a sign in request should be made") { expect(signInAPI.signInCalled).to(beTrue()) } context("when sign in response arrives") { beforeEach { let signInResponse = SignInResponse(token: "fake_token") signInAPI.signInReturnValue.on(.next(signInResponse)) } it("should give an event with the correct sign in response") { expect(signInResponse.token).to(equal("fake_token")) } } } } } } } } }
80. Easy to write Don’t have to think timeline of events right from the start Don’t have to think expected events right from the start ❌ Nesting ❌ Do not test when events are emitted Easy to read
81. Set the timeline of events ☑ by using PublishSubject ☑ by using RxBlocking ☑ by using TestScheduler ☑ by using Marble Syntax
82. RxBlocking ReplaySubject import RxBlocking Blocks the current thread and waits for the sequence to complete, allowing to synchronously access its result .toBlocking() => converts a regular observable sequence to a blocking observable .toArray() => returns an array of elements emitted once a sequence is completed PublishSubject doesn’t work with RxBlocking (doesn’t replay the events)
83. class SignInViewModelRxBlockingSpec: QuickSpec { override func spec() { describe("The SignInViewModel") { }
84. var emailText: ReplaySubject<String>! var passwordText: ReplaySubject<String>! var signInButtonTap: ReplaySubject<Void>! beforeEach { //Use ReplaySubject instead of PublishSubject emailText = ReplaySubject<String>.create(bufferSize: 10) passwordText = ReplaySubject<String>.create(bufferSize: 10) signInButtonTap = ReplaySubject<Void>.create(bufferSize: 10) sut.configure(emailText: emailText, passwordText: passwordText, signInButtonTap: signInButtonTap) } } } class SignInViewModelRxBlockingSpec: QuickSpec { override func spec() { describe("The SignInViewModel") { }
85. class SignInViewModelRxBlockingSpec: QuickSpec { override func spec() { describe("The SignInViewModel") { // <initial properties here> var emailText: ReplaySubject<String>! var passwordText: ReplaySubject<String>! var signInButtonTap: ReplaySubject<Void>! beforeEach { //Use ReplaySubject instead of PublishSubject emailText = ReplaySubject<String>.create(bufferSize: 10) passwordText = ReplaySubject<String>.create(bufferSize: 10) signInButtonTap = ReplaySubject<Void>.create(bufferSize: 10) sut.configure(emailText: emailText, passwordText: passwordText, signInButtonTap: signInButtonTap) } } }
86. it("should get an initial event that sign in should not be enabled") { let signInButtonEnabled = try! sut.signInButtonEnabled.toBlocking().first() expect(signInButtonEnabled).to(beFalse()) } it("should get another event that sign in button should not be enabled") { let signInButtonEnabled = try! sut.signInButtonEnabled.toBlocking().toArray() expect(signInButtonEnabled).to(equal([false, false])) }
87. context("when an invalid email is typed") { beforeEach { emailText.on(.next("test@")) emailText.on(.completed) } it("should get an event that email is invalid") { let emailIsValid = try! sut.emailIsValid.toBlocking().first() expect(emailIsValid).to(beFalse()) } context("when an invalid password is typed") { beforeEach { passwordText.on(.next("asd")) passwordText.on(.completed) } it("should get an event that password is invalid") { let passwordIsValid = try! sut.passwordIsValid.toBlocking().first() expect(passwordIsValid).to(beFalse()) } it("should get another event that sign in button should not be enabled") { let signInButtonEnabled = try! sut.signInButtonEnabled.toBlocking().toArray() expect(signInButtonEnabled).to(equal([false, false])) } } } it("should get an initial event that sign in should not be enabled") { let signInButtonEnabled = try! sut.signInButtonEnabled.toBlocking().first() expect(signInButtonEnabled).to(beFalse()) }
88. context("when an invalid email is typed") { beforeEach { emailText.on(.next("test@")) emailText.on(.completed) } it("should get an event that email is invalid") { let emailIsValid = try! sut.emailIsValid.toBlocking().first() expect(emailIsValid).to(beFalse()) } context("when an invalid password is typed") { beforeEach { passwordText.on(.next("asd")) passwordText.on(.completed) } it("should get an event that password is invalid") { let passwordIsValid = try! sut.passwordIsValid.toBlocking().first() expect(passwordIsValid).to(beFalse()) } it("should get another event that sign in button should not be enabled") { let signInButtonEnabled = try! sut.signInButtonEnabled.toBlocking().toArray() expect(signInButtonEnabled).to(equal([false, false])) } } } it("should get an initial event that sign in should not be enabled") { let signInButtonEnabled = try! sut.signInButtonEnabled.toBlocking().first() expect(signInButtonEnabled).to(beFalse()) }
89. context("when an invalid email is typed") { beforeEach { emailText.on(.next("test@")) emailText.on(.completed) } it("should get an event that email is invalid") { let emailIsValid = try! sut.emailIsValid.toBlocking().first() expect(emailIsValid).to(beFalse()) } context("when an invalid password is typed") { beforeEach { passwordText.on(.next("asd")) passwordText.on(.completed) } it("should get an event that password is invalid") { let passwordIsValid = try! sut.passwordIsValid.toBlocking().first() expect(passwordIsValid).to(beFalse()) } it("should get another event that sign in button should not be enabled") { let signInButtonEnabled = try! sut.signInButtonEnabled.toBlocking().toArray() expect(signInButtonEnabled).to(equal([false, false])) } } } it("should get an initial event that sign in should not be enabled") { let signInButtonEnabled = try! sut.signInButtonEnabled.toBlocking().first() expect(signInButtonEnabled).to(beFalse()) }
90. class SignInViewModelRxBlockingSpec: QuickSpec { override func spec() { describe("The SignInViewModel") { beforeEach { //initialization code here } it("should get an initial event that sign in should not be enabled") { let signInButtonEnabled = try! sut.signInButtonEnabled.toBlocking(timeout: 3).first() expect(signInButtonEnabled).to(beFalse()) } context("when an invalid email is typed") { beforeEach { emailText.on(.next("test@")) emailText.on(.completed) } it("should get an event that email is invalid") { let emailIsValid = try! sut.emailIsValid.toBlocking(timeout: 3).toArray().first expect(emailIsValid).to(beFalse()) } context("when an invalid password is typed") { beforeEach { passwordText.on(.next("asd")) passwordText.on(.completed) } it("should get an event that password is invalid") { let passwordIsValid = try! sut.passwordIsValid.toBlocking(timeout: 3).first() expect(passwordIsValid).to(beFalse()) } it("should get another event that sign in button should not be enabled") { let signInButtonEnabled = try! sut.signInButtonEnabled.toBlocking(timeout: 3).toArray() expect(signInButtonEnabled).to(equal([false, false])) } } } context("when valid email and password are typed") { beforeEach { emailText.on(.next("test@gmail.com")) emailText.on(.completed) passwordText.on(.next("Asd123!!")) passwordText.on(.completed) } it("should get an event that email is valid") { let emailIsValidSecondEvent = try! sut.emailIsValid.toBlocking(timeout: 3).first() expect(emailIsValidSecondEvent).to(beTrue()) } it("should get an event that password is valid") { let passwordIsValidSecondEvent = try! sut.passwordIsValid.toBlocking(timeout: 3).first() expect(passwordIsValidSecondEvent).to(beTrue()) } it("should get an event that sign in button should be enabled") { let signInButtonEnabledThirdEvent = try! sut.signInButtonEnabled.toBlocking(timeout: 3).toArray() expect(signInButtonEnabledThirdEvent).to(equal([false, true])) } context("when sign in button is tapped") { beforeEach { rememberEmail.on(.next(false)) rememberEmail.on(.completed) signInButtonTap.on(.next(())) signInButtonTap.on(.completed) } it("a sign in request should be made") { expect(signInAPI.signInCalled).to(beTrue()) } context("when response arrives") { beforeEach { signInAPI.signInReturnValue.on(.next(SignInResponse(email: "test@gmail.com", account: "workable"))) signInAPI.signInReturnValue.onCompleted() } it("should have the correct response emition") { let signInAction = try? sut.signInAction.toBlocking(timeout: 3).first() expect(signInAction).to(equal(SignInResponse(email: "test@gmail.com", account: "workable"))) } } } } } } }
91. ❌ Additional completed events Easy to write We don’t have to think expected events right from the start Easy to read We don’t have to think timeline of events right from the start ❌ Can’t use a PublishSubject ❌ Do not test when events are emitted ❌ Can’t use for non-terminating sequences ❌ Blocks current thread thus tests taking longer
92. Set the timeline of events ☑ by using PublishSubject ☑ by using RxBlocking ☑ by using TestScheduler ☑ by using Marble Syntax
93. TestScheduler •Provided by RxTest => import RxTest •It simplifies testing time-based events •Enables creating mock Observables and Observers •Enables us to “record” these events and test them •Clock: Virtual Time
94. TestScheduler • Provided by RxTest => import RxTest •It simplifies testing time-based events •Enables creating mock Observables and Observers •Enables us to “record” these events and test them •Clock: Virtual Time
95. TestScheduler • Provided by RxTest => import RxTest • It simplifies testing time-based events •Enables creating mock Observables and Observers •Enables us to “record” these events and test them •Clock: Virtual Time
96. TestScheduler • Provided by RxTest => import RxTest • It simplifies testing time-based events • Enables creating mock Observables and Observers •Enables us to “record” these events and test them •Clock: Virtual Time
97. TestScheduler • Provided by RxTest => import RxTest • It simplifies testing time-based events • Enables creating mock Observables and Observers • Enables us to “record” these events and test them •Clock: Virtual Time
98. TestScheduler • Provided by RxTest => import RxTest • It simplifies testing time-based events • Enables creating mock Observables and Observers • Enables us to “record” these events and test them • Clock: Virtual Time
99. Testable Observer let scheduler = TestScheduler(initialClock: 0)
100. Testable Observer let scheduler = TestScheduler(initialClock: 0) var emailIsValidObserver: TestableObserver<Bool> = scheduler.createObserver(Bool.self)
101. Testable Observer // Listen for the events sut.emailIsValid.subscribe(emailIsValidObserver).disposed(by: disposeBag) let scheduler = TestScheduler(initialClock: 0) var emailIsValidObserver: TestableObserver<Bool> = scheduler.createObserver(Bool.self)
102. Testable Observer // Listen for the events sut.emailIsValid.subscribe(emailIsValidObserver).disposed(by: disposeBag) let scheduler = TestScheduler(initialClock: 0) var emailIsValidObserver: TestableObserver<Bool> = scheduler.createObserver(Bool.self) it("should get an event that email is invalid") { expect(emailIsValidObserver.events.first?.value.element).to(beFalse()) }
103. beforeEach { emailIsValidObserver = scheduler.createObserver(Bool.self) passwordIsValidObserver = scheduler.createObserver(Bool.self) signInButtonEnabledObserver = scheduler.createObserver(Bool.self) signInObserver = scheduler.createObserver(SignInResponse.self) }
104. beforeEach { emailIsValidObserver = scheduler.createObserver(Bool.self) passwordIsValidObserver = scheduler.createObserver(Bool.self) signInButtonEnabledObserver = scheduler.createObserver(Bool.self) signInObserver = scheduler.createObserver(SignInResponse.self) scheduler.scheduleAt(0, action: { sut.emailIsValid.subscribe(emailIsValidObserver).disposed(by: disposeBag) sut.passwordIsValid.subscribe(passwordIsValidObserver).disposed(by: disposeBag) sut.signInButtonEnabled.subscribe(signInButtonEnabledObserver).disposed(by: disposeBag) sut.signInAction.subscribe(signInActionObserver).disposed(by: disposeBag) }) }
105. beforeEach { scheduler.scheduleAt(1, action: { emailText.on(.next("test@")) }) }
106. beforeEach { scheduler.scheduleAt(1, action: { emailText.on(.next("test@")) }) scheduler.scheduleAt(2, action: { passwordText.on(.next("asd")) }) }
107. beforeEach { scheduler.scheduleAt(1, action: { emailText.on(.next("test@")) }) scheduler.scheduleAt(2, action: { passwordText.on(.next("asd")) }) scheduler.scheduleAt(3, action: { emailText.on(.next("test@gmail.com")) passwordText.on(.next("Asd123!!")) }) }
108. beforeEach { scheduler.scheduleAt(1, action: { emailText.on(.next("test@")) }) scheduler.scheduleAt(2, action: { passwordText.on(.next("asd")) }) scheduler.scheduleAt(3, action: { emailText.on(.next("test@gmail.com")) passwordText.on(.next("Asd123!!")) }) scheduler.scheduleAt(4, action: { signInButtonTap.on(.next(())) }) }
109. beforeEach { scheduler.scheduleAt(1, action: { emailText.on(.next("test@")) }) scheduler.scheduleAt(2, action: { passwordText.on(.next("asd")) }) scheduler.scheduleAt(3, action: { emailText.on(.next("test@gmail.com")) passwordText.on(.next("Asd123!!")) }) scheduler.scheduleAt(4, action: { signInButtonTap.on(.next(())) }) scheduler.scheduleAt(5, action: { signInAPI.signInReturnValue.on(.next(SignInResponse(token: "fake_token"))) }) }
110. beforeEach { scheduler.scheduleAt(1, action: { emailText.on(.next("test@")) }) scheduler.scheduleAt(2, action: { passwordText.on(.next("asd")) }) scheduler.scheduleAt(3, action: { emailText.on(.next("test@gmail.com")) passwordText.on(.next("Asd123!!")) }) scheduler.scheduleAt(4, action: { signInButtonTap.on(.next(())) }) scheduler.scheduleAt(5, action: { signInAPI.signInReturnValue.on(.next(SignInResponse(token: "fake_token"))) }) scheduler.start() }
111. it("should get an initial event that sign in should not be enabled") { expect(signInButtonEnabledObserver.events.first?.value.element).to(beFalse()) } it("should get an event that email is invalid") { expect(emailIsValidObserver.events.first?.value.element).to(beFalse()) } it("should get an event that password is invalid") { expect(passwordIsValidObserver.events.first?.value.element).to(beFalse()) } it("should get an event that sign in button should not be enabled") { let secondEvent = signInButtonEnabledObserver.events[1].value.element expect(secondEvent).to(beFalse()) } it("should get an event that email is valid") { let secondEvent = emailIsValidObserver.events[1].value.element expect(secondEvent).to(beTrue()) }
112. it("should get an initial event that sign in should not be enabled") { expect(signInButtonEnabledObserver.events.first?.value.element).to(beFalse()) } it("should get an event that email is invalid") { expect(emailIsValidObserver.events.first?.value.element).to(beFalse()) } it("should get an event that password is invalid") { expect(passwordIsValidObserver.events.first?.value.element).to(beFalse()) } it("should get an event that sign in button should not be enabled") { let secondEvent = signInButtonEnabledObserver.events[1].value.element expect(secondEvent).to(beFalse()) } it("should get an event that email is valid") { let secondEvent = emailIsValidObserver.events[1].value.element expect(secondEvent).to(beTrue()) }
113. it("should get an event that password is valid") { let secondEvent = emailIsValidObserver.events[1].value.element expect(secondEvent).to(beTrue()) } it("should get an event that sign in button should be enabled") { let secondEvent = signInButtonEnabledObserver.events[3].value.element expect(secondEvent).to(beTrue()) } it("a sign in request should be made") { expect(signInAPI.signInCalled).to(beTrue()) } it("should give an event with the correct sign in response") { expect(signInActionObserver.events.first?.value.element?.token).to(equal(“fake_token")) }
115. Testable Observable var emailText: TestableObservable<String>
116. Testable Observable var emailText: TestableObservable<String> var emailText: TestableObservable<String>! = scheduler.createHotObservable( [.next(1, "test@"), .next(3, "test@gmail.com")])
117. Testable Observable var emailText: TestableObservable<String> var emailText: TestableObservable<String>! = scheduler.createHotObservable( [.next(1, "test@"), .next(3, "test@gmail.com")]) // Replace Publish subject with testable observables sut.configure(emailText: emailText.asObservable(), ….
118. beforeEach { emailText = scheduler.createHotObservable( [.next(1, "test@"), .next(3, "test@gmail.com")]) passwordText = scheduler.createHotObservable([.next(2, "asd"), .next(3, "Asd123!!")]) signInButtonTap = scheduler.createHotObservable([.next(4, ())]) // Fake the input sut.configure(emailText: emailText.asObservable(), passwordText: passwordText.asObservable(), signInButtonTap: signInButtonTap.asObservable()) }
120. // Array of expected for the events let emailIsValidExpectedEvents: [Recorded<Event<Bool>>] = [ .next(1, false), .next(3, true) ] var emailText: TestableObservable<String>! = scheduler.createHotObservable( [.next(1, "test@"), .next(3, "test@gmail.com")]) Test time as well
121. beforeEach { emailIsValidExpectedEvents = [ .next(1, false), .next(3, true) ] passwordIsValidExpectedEvents = [ .next(2, false), .next(3, true) ] signInButtonEnabledExpectedEvents = [ .next(0, false) , // start with initial value .next(2, false) , //password invalid type .next(3, false), //for valid email and invalid password type .next(3, true) //for valid email and password type ] signInActionExpectedEvents = [ .next(4, SignInResponse(token: “fake_token")), .completed(4) ] }
122. it("should get the correct signInButtonEnabledEvents") { expect(signInButtonEnabledObserver.events).to(equal(signInButtonEnabledExpectedEvents)) } it("should get the correct emailIsValidExpectedEvents") { expect(emailIsValidObserver.events).to(equal(emailIsValidExpectedEvents)) } it("should get the correct passwordIsValidExpectedEvents") { expect(passwordIsValidObserver.events).to(equal(passwordIsValidExpectedEvents)) } it("a sign in request should be made") { expect(signInAPI.signInCalled).to(beTrue()) } it("should get the correct signInActionObserver") { expect(signInActionObserver.events).to(equal(signInActionExpectedEvents)) }
123. class SignInViewModelTestableObservableSpec: QuickSpec { override func spec() { describe("The SignInViewModel") { //initialization code here beforeEach { signInAPI = SignInAPIFakeObservable() disposeBag = DisposeBag() sut = SignInViewModel(signInAPI: signInAPI, disposeBag: disposeBag) scheduler = TestScheduler(initialClock: 0) emailIsValidObserver = scheduler.createObserver(Bool.self) passwordIsValidObserver = scheduler.createObserver(Bool.self) signInButtonEnabledObserver = scheduler.createObserver(Bool.self) signInActionObserver = scheduler.createObserver(SignInResponse.self) emailText = scheduler.createHotObservable( [.next(1, "test@"), .next(3, "test@gmail.com")]) emailIsValidExpectedEvents = [ .next(1, false), .next(3, true) ] passwordText = scheduler.createHotObservable([.next(2, "asd"), .next(3, "Asd123!!")]) passwordIsValidExpectedEvents = [ .next(2, false), .next(3, true) ] signInButtonTap = scheduler.createHotObservable([.next(4, ())]) let signInResponse = SignInResponse(email: "test@gmail.com", account: "workable") signInAction = scheduler.createColdObservable([.next(0, signInResponse)]) signInAPI.signInReturnValue = signInAction.asObservable() signInButtonEnabledExpectedEvents = [ .next(0, false) , // start with initial value .next(2, false) , //password invalid type (didn't get in email type becasue password didn't get an initial event an //combine latest doesn't work) .next(3, false), //for valid email type .next(3, true) //for valid password type ] signInActionExpectedEvents = [ .next(4, SignInResponse(email: "test@gmail.com", account: "workable")), .completed(4) ] sut.configure(emailText: emailText.asObservable(), passwordText: passwordText.asObservable(), signInButtonTap signInButtonTap.asObservable(), rememberEmail: rememberEmail.asObservable()) scheduler.scheduleAt(0, action: { sut.emailIsValid.subscribe(emailIsValidObserver).disposed(by: disposeBag) sut.passwordIsValid.subscribe(passwordIsValidObserver).disposed(by: disposeBag) sut.signInButtonEnabled.subscribe(signInButtonEnabledObserver).disposed(by: disposeBag) sut.signInAction.subscribe(signInActionObserver).disposed(by: disposeBag) }) scheduler.start() } it("should get the correct signInButtonEnabledEvents") { expect(signInButtonEnabledObserver.events).to(equal(signInButtonEnabledExpectedEvents)) } it("should get the correct emailIsValidExpectedEvents") { expect(emailIsValidObserver.events).to(equal(emailIsValidExpectedEvents)) } it("should get the correct passwordIsValidExpectedEvents") { expect(passwordIsValidObserver.events).to(equal(passwordIsValidExpectedEvents)) } it("a sign in request should be made") { expect(signInAPI.signInCalled).to(beTrue()) } it("should get the correct signInActionObserver") { expect(signInActionObserver.events).to(equal(signInActionExpectedEvents)) } } } }
124. No nesting Easy to read ❌ We have to think expected events right from the start Extra flexibility to test when events are emitted ❌ We have to think timeline of events right from the start Simplifies assertions ❌ Boilerplate initialisation code
125. Set the timeline of events ☑ by using PublishSubject ☑ by using RxBlocking ☑ by using TestScheduler ☑ by using Marble Syntax
126. Marble Syntax Letters and values mark events in a dictionary struct: [a:1, b:true]
127. Marble Syntax Timeline in the form `---a---b------c--|` Letters and values mark events in a dictionary struct: [a:1, b:true]
128. Marble Syntax Timeline in the form `---a---b------c--|` Returns: Observable sequence specified by timeline and values. Letters and values mark events in a dictionary struct: [a:1, b:true]
129. class SignInViewModelMarbleSyntaxSpec: QuickSpec { override func spec() { describe("The SignInViewModel") { // <initial properties here> var emailText: TestableObservable<String>! var passwordText: TestableObservable<String>! var signInButtonTap: TestableObservable<Void>! var signIn: TestableObservable<SignInResponse>! var emailIsValidObserver: TestableObserver<Bool>! var passwordIsValidObserver: TestableObserver<Bool>! var signInButtonEnabledObserver: TestableObserver<Bool>! var signInObserver: TestableObserver<SignInResponse>! var emailIsValidExpectedEvents: [Recorded<Event<Bool>>]! var passwordIsValidExpectedEvents: [Recorded<Event<Bool>>]! var signInButtonEnabledExpectedEvents: [Recorded<Event<Bool>>]! var signInExpectedEvents: [Recorded<Event<SignInResponse>>]! } } } Same properties as before Different initialization
130. Marble Syntax let emails = [ "e1": “test@", "e2": “test@gmail.com"] Letters and values mark events in a dictionary struct: [a:1, b:true]
131. Marble Syntax let emails = [ "e1": “test@", "e2": “test@gmail.com"] let emailEvents = scheduler.parseEventsAndTimes(timeline: "---e1----e2-----", values: emails) Timeline in the form `---a---b------c--|` Letters and values mark events in a dictionary struct: [a:1, b:true]
132. Marble Syntax Returns: Observable sequence specified by timeline and values. let emails = [ "e1": “test@", "e2": “test@gmail.com"] let emailText = scheduler.createHotObservable(emailEvents) let emailEvents = scheduler.parseEventsAndTimes(timeline: "---e1----e2-----", values: emails) Timeline in the form `---a---b------c--|` Letters and values mark events in a dictionary struct: [a:1, b:true]
133. Marble Syntax Returns: Observable sequence specified by timeline and values. let emails = [ "e1": “test@", "e2": “test@gmail.com"] let emailText = scheduler.createHotObservable(emailEvents) let emailEvents = scheduler.parseEventsAndTimes(timeline: "---e1----e2-----", values: emails) Timeline in the form `---a---b------c--|` Letters and values mark events in a dictionary struct: [a:1, b:true]
134. Marble Syntax Returns: Observable sequence specified by timeline and values. let emails = [ "e1": “test@", "e2": “test@gmail.com"] let emailText = scheduler.createHotObservable(emailEvents) let emailEvents = scheduler.parseEventsAndTimes(timeline: "---e1----e2-----", values: emails) Timeline in the form `---a---b------c--|` Letters and values mark events in a dictionary struct: [a:1, b:true]
135. let emails = [ "e1": “test@", "e2": “test@gmail.com"] let emailEvents = scheduler.parseEventsAndTimes(timeline: "---e1----e2-----", values: emails).first! let emailText = scheduler.createHotObservable(emailEvents) sut.configure(emailText: emailText.asObservable() …
136. beforeEach { // input events let emails = [ "e1": “test@", "e2": "test@gmail.com"] let passwords = ["p1": "asd", "p2": "Asd123!!"] let signInButtonTap = ["s1": ()] let emailEvents = scheduler.parseEventsAndTimes(timeline: "---e1----e2-----", values: emails).first! let passwordEvents = scheduler.parseEventsAndTimes(timeline: "-----p1-----p2-----", values: passwords).first! let signInButtonTapEvents = scheduler.parseEventsAndTimes(timeline: "---------------------------s1-", values: signInButtonTap).first! }
137. beforeEach { // input events let emails = [ "e1": “test@", "e2": "test@gmail.com"] let passwords = ["p1": "asd", "p2": "Asd123!!"] let signInButtonTap = ["s1": ()] let emailEvents = scheduler.parseEventsAndTimes(timeline: "---e1----e2-----", values: emails).first! let passwordEvents = scheduler.parseEventsAndTimes(timeline: "-----p1-----p2-----", values: passwords).first! let signInButtonTapEvents = scheduler.parseEventsAndTimes(timeline: "---------------------------s1-", values: signInButtonTap).first! // expected events let emailIsValid = ["v1": false, "v2": true] let passwordIsValid = ["u1" :false, "u2": true] let signInButtonEnabled = ["b1": false, "b2": false, "b3": false, "b4" :true] let signInResponseEvents = ["x1": SignInResponse(email: "test@gmail.com", account: “workable")] expectedEmailIsValidEvents = scheduler.parseEventsAndTimes(timeline: "---v1----v2-----", values: emailIsValid).first! expectedPasswordIsValidEvents = scheduler.parseEventsAndTimes(timeline: "-----u1-----u2-----", values: passwordIsValid) .first! signInEnabledExpectedEvents = scheduler.parseEventsAndTimes(timeline: "b1---b2--b3-b4--", values: signInButtonEnabled) .first! signInExpectedEvents = scheduler.parseEventsAndTimes(timeline: "---------------------------------x1-", values: signInResponseEvents).first! }
138. it("should get the correct signInButtonEnabledEvents") { expect(signInButtonEnabledObserver.events).to(equal(signInEnabledExpectedEvents)) } it("should get the correct emailIsValidExpectedEvents") { expect(emailIsValidObserver.events).to(equal(expectedEmailIsValidEvents)) } it("should get the correct passwordIsValidExpectedEvents") { expect(passwordIsValidObserver.events).to(equal(expectedPaswordIsValidEvents)) } it("a sign in request should be made") { expect(signInAPI.signInCalled).to(beTrue()) } it("should get the correct signInActionObserver") { expect(signInActionObserver.events.first).to(equal(signInActionExpectedEvents.first)) }
139. class SignInViewModelMarbleSyntaxSpec: QuickSpec { override func spec() { describe("The SignInViewModel") { //initialization code here beforeEach { signInAPI = SignInAPIFake() disposeBag = DisposeBag() sut = SignInViewModel(signInAPI: signInAPI, disposeBag: disposeBag) scheduler = TestScheduler(initialClock: 0) emailIsValidObserver = scheduler.createObserver(Bool.self) passwordIsValidObserver = scheduler.createObserver(Bool.self) signInObserver = scheduler.createObserver(SignInResponse.self) let emails = ["e1": "test@", "e2": "test@gmail.com"] let passwords = ["p1": "asd", "p2": "Asd123!!"] let rememberEmailEvent = ["r1": false] let signInButtonClick = ["s1": ()] let emailEvents = scheduler.parseEventsAndTimes(timeline: "---e1----e2-----", values: emails).first! let passwordEvents = scheduler.parseEventsAndTimes(timeline: "-----p1-----p2-----", values: passwords).first! let signInButtonTapEvents = scheduler.parseEventsAndTimes(timeline: "---------------------------s1-", values: signInButtonClick).first! let emailIsValid = ["v1": false, "v2": true] let passwordIsValid = ["u1" :false, "u2": true] let signInButtonEnabled = ["b1": false, "b2": false, "b3": false, "b4" :true] let signInResponseEvents = ["x1": SignInResponse(email: "test@gmail.com", account: "workable")] expectedEmailIsValidEvents = scheduler.parseEventsAndTimes(timeline: "---v1----v2-----", values: emailIsValid).first! expectedPaswordIsValidEvents = scheduler.parseEventsAndTimes(timeline: "-----u1-----u2-----", values: passwordIsValid).first! signInEnabledExpectedEvents = scheduler.parseEventsAndTimes(timeline: "b1---b2--b3-b4--", values: signInButtonEnabled).first! signInExpectedEvents = scheduler.parseEventsAndTimes(timeline: "---------------------------------x1-", values: signInResponseEvents).first! emailText = scheduler.createHotObservable( emailEvents) passwordText = scheduler.createHotObservable(passwordEvents) signInButtonTap = scheduler.createHotObservable(signInButtonTapEvents) sut.configure(emailText: emailText.asObservable(), passwordText: passwordText.asObservable(), signInButtonTap: signInButtonTap.asObservable()) sut.emailIsValid.subscribe(emailIsValidObserver).disposed(by: disposeBag) sut.passwordIsValid.subscribe(passwordIsValidObserver).disposed(by: disposeBag) sut.signInButtonEnabled.subscribe(signInButtonEnabledObserver).disposed(by: disposeBag) sut.signIn.subscribe(signInActionObserver).disposed(by: disposeBag) scheduler.scheduleAt(33, action: { signInAPI.signInReturnValue.on(.next(SignInResponse(email: "test@gmail.com", account: "workable"))) }) scheduler.start() } it("should get the correct signInButtonEnabledEvents") { expect(signInButtonEnabledObserver.events).to(equal(signInEnabledExpectedEvents)) } it("should get the correct emailIsValidExpectedEvents") { expect(emailIsValidObserver.events).to(equal(expectedEmailIsValidEvents)) } it("should get the correct passwordIsValidExpectedEvents") { expect(passwordIsValidObserver.events).to(equal(expectedPaswordIsValidEvents)) } it("a sign in request should be made") { expect(signInAPI.signInCalled).to(beTrue()) } it("should get the correct signInActionObserver") { expect(signInObserver.events.first).to(equal(signInExpectedEvents.first)) } } } }
140. ❌ Difficult to read No nesting ❌ We have to think expected events right from the start Extra flexibility to test when events are emitted ❌ We have to think timeline of events right from the start ❌ Difficult to write
141. Confused?
142. Think about it this way: Then, you assert your output to make sure that it emits the expected events at the right times. You fake a stream of events and feed it into your view model’s input
143. Conclusions Different ways to unit test a component Each one has pros & ❌ cons Select the one that suits your needs
144. Thank you https://github.com/elenipapanik/SignInApp.git