NSFileManagerAdditions.swift

//
//  Copyright (c) 2014 Tony Arnold & The CocoaBots. All rights reserved.

import Foundation

extension NSFileManager
{

    func applicationSupportDirectoryURL() -> NSURL?
    {
        let directories = URLsForDirectory(
            NSSearchPathDirectory.ApplicationSupportDirectory,
            inDomains: NSSearchPathDomainMask.UserDomainMask)

        if let directoryURL = directories[directories.endIndex - 1] as? NSURL
        {
            return directoryURL
        }

        return nil
    }

    
}

NSFileManagerAdditionsTests.swift

//
//  Copyright (c) 2014 Tony Arnold & The CocoaBots. All rights reserved.

import XCTest
import SwiftlyCoreData

class NSFileManagerAdditions: XCTestCase
{

    func testApplicationSupportDirectoryURLWorks()
    {
        let appSupport = NSFileManager.applicationSupportDirectoryURL()
        XCTAssertNotNil(appSupport, message: "Should not be nil")
    }

}

@tonyarnold this seemed to work for me (not in the playground tho)

extension NSFileManager
  {

  class func applicationSupportDirectoryURL() -> NSURL? {
    return defaultManager().applicationSupportDirectoryURL()
  }

  func applicationSupportDirectoryURL() -> NSURL?
  {
    let directories = URLsForDirectory(
      NSSearchPathDirectory.ApplicationSupportDirectory,
      inDomains: .UserDomainMask)

    return directories[directories.endIndex - 1] as? NSURL
  }
}

edit: condensing code

Thanks @vascoorey — I get the errors above regardless of whether I declare/use a class function. I think it's a bug.

Damn that's weird indeed @tonyarnold !