Pointers for UI testing in swift

AppDelegate.swift

func application(_ application: UIApplication,
                 didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.
    if NSClassFromString("XCTestCase") != nil {
        return true
    }

    // Setup Code 1 - Do any setup that is needed for both the app and UI tests e.g. global styling

    if ProcessInfo.processInfo.arguments.contains("UITestingEnabled") {
        if let launchViewController = ProcessInfo.processInfo.environment["launchViewController"],
            let screen = LaunchScreen(rawValue: launchViewController) {
            let viewController = self.viewController(for: screen)
            setupWindow(rootViewController: UINavigationController(rootViewController: viewController))
        } else {
            // Default state if we've forgotten to pass a launchViewController or it's not a valid LaunchScreen
            setupWindow(rootViewController: UIViewController())
        }

        return true
    }

    // Setup Code 2 - Do any setup that is only needed by the app

    return true
}

enum LaunchScreen: String {
    case productList
    case productDetail
    case basket
    case payment
    case confirmation
}

private func viewController(for screen: LaunchScreen) -> UIViewController {
    switch screen {
    case .productList:
        return viewControllerForProductList()
    case .productDetail:
        return viewControllerForProductDetail()
    case .basket:
        return viewControllerForBasket()
    case .payment:
        return viewControllerForPayment()
    case .confirmation:
        return viewControllerForConfirmation()
    }
}

private func viewControllerForXXX() -> UIViewController {
    // return a subclass of UIViewController
}

private func setupWindow(rootViewController: UIViewController) {
    self.window = UIWindow(frame: UIScreen.main.bounds)
    self.window?.rootViewController = rootViewController
    self.window?.makeKeyAndVisible()
}