Added webAuth method to Authentication, spawn new WebAuth instance

Added tests

Auth0/Auth0Authentication.swift

@@ -184,4 +184,8 @@ struct Auth0Authentication: Authentication {
         let delegation = URL(string: "/delegation", relativeTo: self.url)!
         return Request(session: session, url: delegation, method: "POST", handle: plainJson, payload: payload, logger: self.logger, telemetry: self.telemetry)
     }
+
+    func webAuth(withConnection connection: String) -> WebAuth {
+        return SafariWebAuth(clientId: self.clientId, url: self.url, presenter: ControllerModalPresenter(), telemetry: self.telemetry).connection(connection)
+    }
 }

Auth0/Authentication.swift

@@ -396,6 +396,22 @@ public protocol Authentication: Trackable, Loggable {
      - returns: a request that will yield the result of delegation
     */
     func delegation(withParameters parameters: [String: Any]) -> Request<[String: Any], AuthenticationError>
+
+    /**
+     Creates a new WebAuth compliant instance using authentication credentials
+     and telemetry.
+
+     ```
+     Auth0
+        .authentication(clientId: clientId, domain: "samples.auth0.com")
+        .webAuth(withConnection: "facebook")
+        .start { print($0) }
+     ```
+
+     - parameter connection: name of the connection to use.
+     - returns: a newly created WebAuth compliant object.
+     */
+    func webAuth(withConnection connection: String) -> WebAuth
 }
 
 /**
@@ -682,4 +698,22 @@ public extension Authentication {
     public func loginSocial(token: String, connection: String, scope: String = "openid", parameters: [String: Any] = [:]) -> Request<Credentials, AuthenticationError> {
         return self.loginSocial(token: token, connection: connection, scope: scope, parameters: parameters)
     }
+
+    /**
+     Creates a new WebAuth compliant instance using authentication credentials
+     and telemetry.
+
+     ```
+     Auth0
+        .authentication(clientId: clientId, domain: "samples.auth0.com")
+        .webAuth(withConnection: "facebook")
+        .start { print($0) }
+     ```
+
+     - parameter connection: name of the connection to use.
+     - returns: a newly created WebAuth compliant object.
+     */
+    public func webAuth(withConnection connection: String) -> WebAuth {
+        return self.webAuth(withConnection: connection)
+    }
 }

Auth0Tests/AuthenticationSpec.swift

@@ -722,5 +722,19 @@ class AuthenticationSpec: QuickSpec {
 
         }
 
+        describe("spawn WebAuth instance") {
+
+            it("should return a WebAuth instance with matching authentication credentials") {
+                let webAuth = auth.webAuth(withConnection: "facebook")
+                expect(webAuth.clientId) == auth.clientId
+                expect(webAuth.url) == auth.url
+            }
+
+            it("should return a WebAuth instance with matching connection") {
+                let webAuth = auth.webAuth(withConnection: "facebook") as! SafariWebAuth
+                expect(webAuth.parameters["connection"]) == "facebook"
+            }
+        }
+
     }
 }