Have a site without a server and want to test the speed?
Login to Synology using SSH via Putty and navigate to somewhere writable e.g. Volume1
cd /Volumes/Volume1/
wget https://raw.githubusercontent.com/sivel/speedtest-cli/master/speedtest.py
Make the speedtest.py script executable.
chmod +x speedtest.py
Run SpeedTest
./speedtest.py