I guess that I have read (and used) too much XP driven programming and testing, so I started devising tests after each sysadmin change also. So, here are some tips assorted by services:

smtp

Test all MX records for domain bobcatsss2008.org by sending e-mail to test@bobcatsss2008.org

host -t mx bobcatsss2008.org | awk '{ print $4 }' | xargs -i swaks  -t test@bobcatsss2008.org -s {}

dns

Dumps all zones from all name servers.

host -t ns bobcatsss2008.org | awk '{ print $3 }' | xargs -i host -t soa -va bobcatsss2008.org {}