Radio faded out then car would not start

[Its-Sam]

I made it home and turned off the engine but had the radio playing as I finished reading mail. After a few minutes, the radio got staticky then faded out completely. I turned the ignition off completely then attempted to start the car and it would not start. I tried several times to start the car. Twice it clicked and one time it did nothing. After about an hour I tried again and it turned over real slow but did not start. The next morning it turned over slowly but did start so I took it to the dealership. After a 3 hour wait, I was as told the battery tested good and the starter passed the test. The car has started continuously since the first episode. But I’d like to know the cause so I can get it corrected before I end up stranded somewhere. Does anyone have any ideas or suggestions on what is going on?