public async Task AddAsync_MessageArgumentIsValid_AddsMessageToDatabaseAndSendsItToClientWithUserId()
        {
            var clientProxyMock = new Mock <IClientProxy>();

            _hubClientsMock.Setup(obj => obj.User(_notification.UserId.ToString()))
            .Returns(clientProxyMock.Object);


            await _service.AddAsync(_messageDto);

            _notificationsRepositoryMock.Verify(
                obj => obj.Add(It.Is <Notification>(notification =>
                                                    notification.ReceiverUserId == _messageDto.UserId && notification.Message == _messageDto.Message &&
                                                    notification.Action == (NotificationAction)4)),
                Times.Once);
            _notificationsRepositoryMock.Verify(obj => obj.SaveChangesAsync());
        }
        public async Task <ActionResult> Add(MessageDto message)
        {
            await _notificationsService.AddAsync(message);

            return(Ok());
        }