SITUATION: You have a tor relay. You say to yourself, "self, is my directory server working?"
SOLUTION: Check this URL:
Where $RELAY_ADDRESS is the, uh, address of your tor relay. Remember the directory port number. The default is 9030.
Also, reference: https://gitweb.torproject.org/torspec.git?a=blob_plain;hb=HEAD;f=dir-spec-v2.txt, search for "/tor/".