Problem with Altenator?

What is your question?

vehicle started ok and drove great. I stopped at a resturant for dinner and when I came back the truck just clicked when attempting to start it. Strange that without the key on the electric windows and radio still functioned. Jumpoered to get truck started. Ampmeter registered about 10 amps. Drove truck home and the final block it died and had to coast into driveway. I removed the altenator and took it into O'Reilly's to get it tested and was told it was working fine. What could be the problem?