While mum was gone

So our mum went to our church, it was just across the street. She told us while she's gone never answer the door, never answer the phone no matter who it is. So we cleaned up while she was gone and we made breakfast, it was only me and my brother. Then suddenly someone knocked on the door, me and my brother just stayed quiet, so he or she kept knocking, then it was my mum, she was testing us if we would listen to her or not