>trick question, you cannot

  [Unit]
  Description=The Apache HTTP Server
  After=remote-fs.target nss-lookup.target
  [Service]
  Type=notify
  EnvironmentFile=/etc/sysconfig/httpd
  ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND
  ExecReload=/usr/sbin/httpd $OPTIONS -k graceful
  ExecStop=/usr/sbin/httpd $OPTIONS -k graceful-stop
  KillSignal=SIGCONT
  PrivateTmp=true
  [Install]
  WantedBy=multi-user.target

and 'apachectl configtest' or 'nginx -t' iirc