public async Task InvokesAddEventSignupAsyncWithCorrectEventSignup()
{
var message = new AddEventSignupCommandAsync { EventSignup = new EventSignup() };
var dataAccess = new Mock<IAllReadyDataAccess>();
var sut = new AddEventSignupCommandHandlerAsync(dataAccess.Object);
await sut.Handle(message);
dataAccess.Verify(x => x.AddEventSignupAsync(message.EventSignup));
}