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()); }