Postfix+spamassassin - how can I test LMTP dovecot?


My postfix configuration is quite complex with a lot of special cases
and rules. However I'd like to make an anti-spam configuration as simple
and lightweight as possible (KISS).

spamassassin unix - n n - - pipe
user=nobody argv=/usr/bin/vendor_perl/spamc -e /usr/sbin/sendmail -oi
-f ${sender} ${recipient}
then the simplest sieve rule I can think of:
I'd like to make this rule active for local deliveries only via dovecot
LMTP with sieve plugin and setting postfix `mailbox_transport' (or
`local_transport') to dovecot LMTP.

I believe it is so simple it should work (am I wrong?). But...
It would be more convenient to do some tests before applying changes to
a production environment config. The problem is: I have no separate
testing environment with my strange configuration :-( I ' able to test a
spamassassin score for an e-mail manually. Can I test local mail
delivery by dovecot LMTP manually? I mean: to simulate "I'm the Postfix"
and produce for some testing e-mail the same effect as postfix granting
it via `local_transport' to dovecot?

Best regards,