Swiftのapplication openURLでハマるの巻 ref: http://qiita.com/ottati/items/c237c75b3141dbec2164

file0.swift

func application(application: UIApplication!, openURL url: NSURL, sourceApplication: String, annotation: AnyObject?) -> Bool {
    return true
}

file1.swift

@IBAction func openButton(sender: AnyObject) {
    let strUrl = "test://"
    let url = NSURL(string: strUrl)
    self.extensionContext?.openURL(url, completionHandler: nil)
}

file2.swift

func application(application: UIApplication!, openURL url: NSURL, sourceApplication: String!, annotation: AnyObject?) -> Bool {
    println(sourceApplication)  // nil
    return true
}