Any channel with a server can allow you to test it, or just ask someone with a fast connection to send you something to test it with.
As far as speed test sites, they tend to be very inaccurate. You can get a *general* idea if you compare speeds from many sites and get an average, but it's still not very accuate.
And, in the end, it doesn't really matter. You can't really change your speed (other than changing ISPs or plans), so you have to take what you can get.
