public async Task AddEventManager()
        {
            var handler = new CreateEventManagerCommandHandler(Context);
            await handler.Handle(new CreateEventManagerCommand
            {
                EventId = _eventId,
                UserId  = _userId
            });

            Context.EventManagers.Count().ShouldBe(1);
            Context.EventManagers.First().EventId.ShouldBe(_eventId);
            Context.EventManagers.First().UserId.ShouldBe(_userId);
        }
        public async Task NotAddEventManagerIfAllreadyExist()
        {
            Context.EventManagers.Add(new EventManager
            {
                EventId = _eventId,
                UserId  = _userId
            });

            Context.SaveChanges();

            Context.EventManagers.Count().ShouldBe(1);

            var handler = new CreateEventManagerCommandHandler(Context);
            await handler.Handle(new CreateEventManagerCommand
            {
                EventId = _eventId,
                UserId  = _userId
            });

            Context.EventManagers.Count().ShouldBe(1);
        }