public async Task throws_when_command_aggregate_has_empty_id(DeleteCalendarItemCycleCommand command)
        {
            command.AggregateId = Guid.Empty;

            var exception = await Record.ExceptionAsync(() => act(command));

            exception.ShouldBeOfType(typeof(AwesomeCalendarException));
            Assert.Equal(((AwesomeCalendarException)exception).Type, AwesomeCalendarExceptionType.InvalidCommand);
        }
 async Task act(DeleteCalendarItemCycleCommand command)
 {
     await DeleteCommandHandler.HandleAsync(command);
 }