@DGM I think it would be better to recommend another speedtest service other than speedtest.net. It uses flash to run the test, but flash is insecure and is going to be deprecated. I would rather recommend speedof.me, which does the test with javascript only, or another one which uses javascript only.

EDIT: Now I saw that a command line client for speedtesting is also needed. There is one for speedtest.net, but none for speedof.me (only paid API access)