Who sings "this my friends is not a test, im rapping to the beat..."?

Question

I don't know the artist, or the song name, just that one line of the chorus. Its an old rap song.

Does anybody know it?

Answer 1

Rapper's Delight - Sugar Hill Gang. It was the first major commercial rap hit. You can listen to the whole thing here:

http://www.youtube.com/watch?v=4-MEL84yXh0

Answer 2

That's "Rapper's Delight" by the Sugar Hill Gang.