MailScanner/SpamAssassin Debug?

[Henry Kwan]

Hi,

Am setting up a MailScanner frontend (CentOS5, Postfix, MailScanner,
SpamAssassin, ClamAV) and everything seems to be up and running but since
I'm currently using a test domain, I'm not getting a lot of emails yet. 
How can I be sure that MailScanner/SpamAssassin is functioning correct? 
When I send test emails from something like GMail, very few SA tests get
triggered.  If I run SpamAssassin by itself and get the expected results,
does that mean everything is OK?

What exactly does "Debug SpamAssassin = yes" do?  There's no apparent
difference in output or in the log file.

Thanks.