UIRefreshControl override so that app correctly idles while UI testing

README.md

UIRefreshControl+testing.swift

You'll need to a -DTESTING compile flag to the configuration you use for testing to enable this extension only for test builds.

UIRefreshControl+testing.swift

//
//  UIRefreshControl+testing.swift
//  Kakhiel
//
//  Created by Koen Punt on 08-02-16.
//  Copyright © 2016 Fetch!. All rights reserved.
//

import Foundation
import UIKit

/** testing Extends UIRefreshControl

*/
#if TESTING

extension UIRefreshControl {
    
    public override class func initialize() {
        struct Static {
            static var token: dispatch_once_t = 0
        }

        // make sure this isn't a subclass
        if self !== UIRefreshControl.self {
            return
        }
        
        dispatch_once(&Static.token) {
            let originalSelector = Selector("_setRefreshControlState:notify:")
            let swizzledSelector = Selector("kp__setRefreshControlState:notify:")
            
            let originalMethod = class_getInstanceMethod(self, originalSelector)
            let swizzledMethod = class_getInstanceMethod(self, swizzledSelector)
            
            let didAddMethod = class_addMethod(self, originalSelector, method_getImplementation(swizzledMethod), method_getTypeEncoding(swizzledMethod))
            
            if didAddMethod {
                class_replaceMethod(self, swizzledSelector, method_getImplementation(originalMethod), method_getTypeEncoding(originalMethod))
            } else {
                method_exchangeImplementations(originalMethod, swizzledMethod)
            }
        }
    }
    
    // MARK: - Method Swizzling
    
    // Overrides so that app idles correctly when running UITests
    func kp__setRefreshControlState(state: Int, notify: Bool) {
        print("state: \(state) notify: \(notify)")
    }

}

#endif

do you have any idea how to do this with the Swift 2.2 selector syntax?