この画像の二つのViewControllerで値を共有したいのですが、ViewController2のラベルに表示されるはずの100が表示されず、消えるはずのラベルが表示されたままです。

状態(画像)
https://teratail.storage.googleapis.com/uploads/contributed_images/997de6dc17a7b4a91f423c6487f0ba85.png

順番としては、
1.AppDelegate.swiftでtastを宣言する
2.ViewControllerで、appDelegate.testに100を入れる
3.ViewController2でtestをtest1で受け取り、ラベルに表示させる
としたつもりです。

少し方法が違ってても全然良いので、異なるView Controllerで値を共有する方法を教えてください。

[appDelegate.swift]

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

var window: UIWindow?
var test:String?


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

func applicationWillResignActive(_ application: UIApplication) {
    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
    // Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.
}

func applicationDidEnterBackground(_ application: UIApplication) {
    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}

func applicationWillEnterForeground(_ application: UIApplication) {
    // Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
}

func applicationDidBecomeActive(_ application: UIApplication) {
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}

func applicationWillTerminate(_ application: UIApplication) {
    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}

}

[ViewController.swift]

import UIKit

class ViewController: UIViewController {
@IBOutlet weak var B: UIButton!
@IBOutlet weak var L: UILabel!
@IBAction func BA(_ sender: AnyObject) {
    let appDelegate:AppDelegate = UIApplication.shared.delegate as!     AppDelegate
    appDelegate.test = String(100)
}




override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

[ViewController2.swift]

import UIKit

class ViewController2: UIViewController {
var test1 = String()

@IBOutlet weak var tetststs: UILabel!
@IBOutlet weak var fsg: UIButton!
@IBOutlet weak var erg: UILabel!

@IBAction func sjrsm(_ sender: AnyObject) {
    tetststs.text = String(test1)
    print(test1)
    if test1 == String(100) {
        erg.isHidden = true

    }
}
override func viewDidLoad() {
    super.viewDidLoad()
    let appDelegate:AppDelegate = UIApplication.shared.delegate as!     AppDelegate

    var test1 = appDelegate.test


    // Do any additional setup after loading the view.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}
}