public void AddTokenToGroup()
        {
            string groupName = $"Group-{Guid.NewGuid().ToString()}";

            FcmGroupHandler fcmGroupHandler = new FcmGroupHandler(_serverKey.Value, _senderId.Value);

            string groupKey = fcmGroupHandler.AddTokenToGroup(groupName, new string[] { _deviceId.Value }).Result;

            // AddTokenToGroup should create new group and return group key
            Assert.AreNotEqual(groupKey, null);

            groupKey = fcmGroupHandler.AddTokenToGroup(groupName, new string[] { _deviceId.Value }).Result;

            // AddTokenToGroup should add token to created group in pervious step
            Assert.AreEqual(groupKey, null);
        }
        public async void SendFcmMessageByGroupKey()
        {
            // Create a test group
            var groupName       = $"Group-{Guid.NewGuid().ToString()}";
            var fcmGroupHandler = new FcmGroupHandler(_serverKey.Value, _senderId.Value);
            var groupKey        = await fcmGroupHandler.AddTokenToGroup(groupName, new string[] { _deviceId.Value });

            // Send message by created group
            FcmMessage message = new FcmMessage
            {
                DryRun       = true,
                To           = groupKey,
                Notification = new FcmNotification
                {
                    Title = "test using c# unit test",
                    Body  = "test"
                }
            };
            FcmSender sender   = new FcmSender(_serverKey.Value, _senderId.Value);
            var       response = sender.Send(message);

            Assert.AreEqual(response.Result.Results, null);
        }