I've been pulling my hair out trying to figure this one out: on Gentoo, this command shows networks tests:
spamassassin -D --lint
However, on Debian, it doesn't. I opened up /usr/bin/spamassassin, and found this:
# bug 5048: --lint should not cause network accesses
if ($opt{'lint'}) { $opt{'local'} = 1; }
Not knowing what bug 5048 is, I still think the lint option should show the network lookups. I use it all the time as a configuration test debugger.
For awhile, I thought the issue had something to do with DNS, but I was wrong.