Set up new Tivo before I have cable service installed?

I am switching from DirecTV to Cox next Sunday. I should have a new Tivo Roamio Plus and a Mini around Wed. this week. I am going to setup the Tivo and Mini on a spare TV this week in order to setup my account and let them download any updates they need. But, since I don't have service or a cable card and tuning adapter, yet, will I have any problems setting up the Tivo since I have nothing to feed it except internet right now?