Another test you could do,is to remove the relay from it's socket, and jumper the pins on the connector. I don't know your mechanical abilities, or if your're comfortable doing this, but if you locate the pins in the socket that correspond to the pin numbers :30 and 87 on the relay you can put a jumper wire across both of them , and if the relay was the problem, the starter should rotate. You may get a little sparking, but you're only going to do this for a second or two. Just make sure the transmission is in neutral, so you don't get any unwelcomed surprise!