Bootstrap custom version of the app for UI tests

ElementX/Sources/AppDelegate.swift

@@ -10,7 +10,7 @@ import UIKit
 @main
 class AppDelegate: UIResponder, UIApplicationDelegate {
     
-    private var appCoordinator: AppCoordinator!
+    private var appCoordinator: Coordinator!
 
     func application(_ application: UIApplication, willFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? = nil) -> Bool {
 
@@ -27,11 +27,11 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
         }
         
         if isRunningUITests {
-            // Bootstrap a different version of the application
-            return true
+            appCoordinator = UITestsAppCoordinator()
+        } else {
+            appCoordinator = AppCoordinator()
         }
         
-        appCoordinator = AppCoordinator()
         appCoordinator.start()
         return true
     }

ElementX/Sources/UITestsAppCoordinator.swift

@@ -0,0 +1,47 @@
+//
+//  UITestsAppCoordinator.swift
+//  ElementX
+//
+//  Created by Stefan Ceriu on 29/04/2022.
+//  Copyright © 2022 element.io. All rights reserved.
+//
+
+import UIKit
+import SwiftUI
+
+class UITestsAppCoordinator: Coordinator {
+    private let window: UIWindow
+    private let mainNavigationController: UINavigationController
+    
+    var childCoordinators: [Coordinator] = []
+    
+    init() {
+        mainNavigationController = UINavigationController()
+        window = UIWindow(frame: UIScreen.main.bounds)
+        window.rootViewController = mainNavigationController
+        
+        let screens = mockScreens()
+        let rootView = UITestsRootView(mockCoordinators: screens) { id in
+            guard let coordinator = screens.filter({ $0.id == id }).first else {
+                fatalError()
+            }
+            
+            self.mainNavigationController.pushViewController(coordinator.coordinator.toPresentable(), animated: true)
+        }
+        
+        mainNavigationController.setViewControllers([UIHostingController(rootView: rootView)], animated: false)
+    }
+    
+    func start() {
+        window.makeKeyAndVisible()
+    }
+    
+    private func mockScreens() -> [MockScreens] {
+        [MockScreens(id: "Login screen", coordinator: LoginScreenCoordinator(parameters: .init()))]
+    }
+}
+
+struct MockScreens: Identifiable {
+    let id: String
+    let coordinator: Presentable
+}

ElementX/Sources/UITestsRootView.swift

@@ -0,0 +1,27 @@
+//
+//  UITestsRootView.swift
+//  ElementX
+//
+//  Created by Stefan Ceriu on 29/04/2022.
+//  Copyright © 2022 element.io. All rights reserved.
+//
+
+import SwiftUI
+
+struct UITestsRootView: View {
+    
+    let mockCoordinators: [MockScreens]
+    var selectionCallback: ((String) -> Void)?
+    
+    var body: some View {
+        NavigationView {
+            List(mockCoordinators) { coordinator in
+                Button(coordinator.id) {
+                    selectionCallback?(coordinator.id)
+                }
+            }
+            .listStyle(.plain)
+        }
+        .navigationTitle("Screens")
+    }
+}