Resetting NSUserDefaults in UI Testing

..md

Resetting NSUserDefaults in UI Testing

1. Add "UI-Testing" to launchArguments before launching the app under test
2. On launch, check for the argument in AppDelegate.swift
3. If it exists remove everything for the app's domain from NSUserDefaults

AppDelegate.swift

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    var window: UIWindow?

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        resetStateIfUITesting()

        window = UIWindow(frame: UIScreen.mainScreen().bounds)
        window?.rootViewController = RootViewController()
        window?.makeKeyAndVisible()
        return true
    }

    private func resetStateIfUITesting() {
        if NSProcessInfo.processInfo().arguments.contains("UI-Testing") {
            NSUserDefaults.standardUserDefaults().removePersistentDomainForName(NSBundle.mainBundle().bundleIdentifier!)
        }
    }
}

UITests.swift

import XCTest

class UITests: XCTestCase {
    private let app = XCUIApplication()

    override func setUp() {
        super.setUp()
        app.launchArguments += ["UI-Testing"]
        app.launch()
    }
}

For swift 4 resetStateIfUITesting will looks like:

private func resetStateIfUITesting() { if ProcessInfo.processInfo.arguments.contains("UI-Testing") { UserDefaults.standard.removePersistentDomain(forName: Bundle.main.bundleIdentifier!) } }

This doesn't work for me anymore (Xcode 9.3.1 atm).

If I print ProcessInfo.processInfo.arguments at application start, any arguments set like app.launchArguments += ["UI-Testing"] aren't set in there.

Works great in Xcode 10!