My starter is not working?

Hi there, My car listed above hasn't been starting on its own for almost two months now. I've taken it to the dealership twice, and each time they've run tests on the battery and the alternator, saying that it never fails the tests. But even after bringing it in a second time, it still will not start. When I turn the key in the ignition, it makes a repeated clicking noise. Any idea if this could be a computer system issue, or something other than the battery or alternator? I just had the battery replaced less than 2 years ago. Thank you so much for your help!