<Location /proxy-tester>
 DAV svn
 SVNPath /path/to/repo
 Order deny,allow
 Deny from all
 # Only let the master server access this Location:
 Allow from master.server.tld
 AuthType Basic
 AuthName "Subversion slave repository tester @ slave.server.tld"
 AuthUserFile /path/to/syncproxy.htpasswd
 Require valid-user
</Location>

<Location />
 Include /path/to/auth.conf
</Location>