Why a little child goes directly to Jannah?

As far as I know, if an Infant or a little kid or child dies he/she goes automatically to Jannah, because he/she hasnt done anything bad. Now My Question is: Isn't it a bit unfair that they don't have to be tested like all of us, and they directly go to jannah for the eternity. Shouldn't we be judged equally? on the same basis? That's just not right.