For some reason, I can never remember the command line options for Exim when testing a new configuration file. I hasten to add this is most likely caused by increasing age rather than Exim being obscure (Exim is considerably less obscure than the more commonly installed Sendmail MTA).
The relevant command is :-
exim -bh ip_address -C config_file -d+all
This starts a command line equivalent to an SMTP network transaction.