change AuthTestClosure args to be string optionals instead

Sources/WebAPI.swift

@@ -35,7 +35,7 @@ public final class WebAPI {
     public typealias HistoryClosure = (_ history: History) -> Void
     public typealias FileClosure = (_ file: File) -> Void
     public typealias ItemsClosure = (_ items: [Item]?) -> Void
-    public typealias AuthTestClosure = (_ user: String, _ team: String) -> Void
+    public typealias AuthTestClosure = (_ user: String?, _ team: String?) -> Void
 
     public enum InfoType: String {
         case purpose, topic
@@ -118,7 +118,7 @@ extension WebAPI {
 extension WebAPI {
     public func authenticationTest(success: AuthTestClosure?, failure: FailureClosure?) {
         networkInterface.request(.authTest, parameters: ["token": token], successClosure: { (response) in
-            success?(response["user_id"] as! String, response["team_id"] as! String)
+            success?(response["user_id"] as? String, response["team_id"] as? String)
         }) {(error) in
             failure?(error)
         }