iOS Swift: Separate AppDelegate for XCTest

Question

Due to a couple issues, I want the XCTest target in a project to run a separate app delegate. Using ObjC, this was a relatively straightforward process: manipulate main.m<

Answer 1

To achieve this is Swift you need to take a couple of steps:

1. If you are using Storyboards, create your view stack programmatically on your AppDelegate.

   Remove Main.storyboard from your project configuration

   Delete @UIApplicationMain from the beginning of your AppDelegate and add this code.

   func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
      let storyboard = UIStoryboard(name: "Main", bundle: nil)
      let vc = storyboard.instantiateInitialViewController()
   
      let window = UIWindow(frame: UIScreen.main.bounds)
      window.rootViewController = vc
   
      window.makeKeyAndVisible()
      self.window = window
   
      return true
   }
   

2. Create a new file at the root your target and call it main.swift.

   Add this code if you don't need to do any setup for your tests

   import UIKit
   
   let kIsRunningTests = NSClassFromString("XCTestCase") != nil
   let kAppDelegateClass = kIsRunningTests ? nil : NSStringFromClass(AppDelegate.self)
   
   UIApplicationMain(CommandLine.argc, CommandLine.unsafeArgv, nil, kAppDelegateClass)
   

   If you need to make some configuration before you run the tests, create a new class FakeAppDelegate as a subclass from NSObject and add your setup code there.

   Put this code in main.swift

   import UIKit
   
   let kIsRunningTests = NSClassFromString("XCTestCase") != nil
   let kAppDelegateClass = kIsRunningTests ? NSStringFromClass(FakeAppDelegate.self) : NSStringFromClass(AppDelegate.self)
   
   UIApplicationMain(CommandLine.argc, CommandLine.unsafeArgv, nil, kAppDelegateClass)