public void UpdateTnsTest()
        {
            var item = new SipPeerTelephoneNumber
            {
                FullNumber  = "Number",
                RewriteUser = "******"
            };

            using (var server = new HttpServer(new RequestHandler
            {
                EstimatedMethod = "PUT",
                EstimatedPathAndQuery = string.Format("/v1.0/accounts/{0}/sites/1/sippeers/10/tns/00", Helper.AccountId),
                EstimatedContent = Helper.ToXmlString(item)
            }))
            {
                var client = Helper.CreateClient();
                var peer   = new SipPeer
                {
                    Id     = "10",
                    SiteId = "1"
                };
                peer.SetClient(client);
                peer.UpdateTns("00", item).Wait();
                if (server.Error != null)
                {
                    throw server.Error;
                }
            }
        }