public async Task SendMessageToAssignedVolunteers()
        {
            var command = new MessageEventVolunteersCommand
            {
                Model = new MessageEventVolunteersModel
                {
                    EventId = 1,
                    Message = "This is my message",
                    Subject = "This is my subject"
                }
            };

            var mediator = new Mock<IMediator>();
            
            var handler = new MessageEventVolunteersCommandHandler(Context, mediator.Object);
            await handler.Handle(command);

            mediator.Verify(b => b.SendAsync(It.Is<NotifyVolunteersCommand>(notifyCommand =>
                   notifyCommand.ViewModel != null &&
                   notifyCommand.ViewModel.EmailMessage == "This is my message" &&
                   notifyCommand.ViewModel.Subject == "This is my subject" &&
                   notifyCommand.ViewModel.EmailRecipients.Count == 2 &&
                   notifyCommand.ViewModel.EmailRecipients.Contains("*****@*****.**") &&
                   notifyCommand.ViewModel.EmailRecipients.Contains("*****@*****.**")

            )), Times.Once());
        }