llinardos

func onMainDo<T>(_ firstMainBlock: @escaping () -> Void, onBackgroundDo backgroundBlock: @escaping () -> T, thenOnMainDo mainBlock: @escaping (T) -> Void) {
    DispatchQueue.main.async {
        firstMainBlock()
        DispatchQueue.global(qos: .background).async {
            let result = backgroundBlock()
            DispatchQueue.main.async {
                mainBlock(result)
            }
        }
    }

llinardos

func startApp() {
  onMainDo({
    self.activityIndicator.startAnimating()
  }, onBackgroundDo: {
    let storage = PersistentSecureStorage.shared()
    guard let savedToken == storage.token {
       return .goToAuth
    }
    let tokenIsValid = authService.isValidToken(savedToken)
    if !tokenIsValid {

llinardos

class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        let vc = StarsViewTestVC()
        window!.rootViewController = vc
        
        return true
    }

llinardos

extension URLSession {
    func sendSynchronousRequest(request: URLRequest) -> (Data?, URLResponse?, Error?) {
        let semaphore = DispatchSemaphore(value: 0)
        
        var result: (data: Data?, response: URLResponse?, error: Error?)
        let task = self.dataTask(with: request) {
            result = (data: $0, response: $1, error: $2)
            semaphore.signal()
        }
        task.resume()

llinardos

let service = SyncronousThingsService()
onMainDo({
    self.activityIndicator.startAnimating()
}, onBackgroundDo: {
    return service.getThings()
}, thenOnMainDo: {
    self.activityIndicator.stopAnimating()
    self.updateUI(with: $0)
})

llinardos

protocol ThingsService {
  func getThings(onCompletion callback: (Result<[Thing]>) -> Void)
  func add(onCompletion callback: (Result<Bool>) -> Void)
}

class FakeThingsService: ThingsService {
  private(set) var things: [Thing]
  
  init(things: [Thing]) {
    self.things = things

llinardos

class ServicesTest: XCTestCase {
  let service = ProfileService()
  
  setup() {
    // handle authentication if needed
    // let authService = ...
    // let authMethod = ...
    // authService.auth(authMethod)
  }
  

llinardos

protocol ThingsService {
  func getThings() -> Result<[Thing]>
  func add(thing: Thing) -> Result<Bool>
}

class FakeThingsService: ThingsService {
  private(set) var things: [Thing]
  init(things: [Thing]) {
    self.things = things
  }

llinardos

class ThingsService {
    func getThings() -> Result<[Thing]> {
        do {
            let response = try sendHttpRequestSynchronously(url)
            let data = try getData(from: response)
            let things = try doParsing(data)
            return .success(things)
        } catch error {
            return .failure(error)
        }

llinardos

class ThingsService {
    func getThings(onCompletion callback: @escaping (Result<[Thing]>) -> Void) {
        sendHttpRequestAsynchronously(url) { response in
            DispatchQueue.main.async {
                do {
                    let data = try getData(from: response)
                    let things = try doParsing(data)
                    callback(.success(things)))
                } catch error {
                    callback(.failure(error))