Do you have time to do a test run cake so you can get an idea of the consistency of the buttercream icing etc?

Depending on the difficulty level of the cake and how much time I will have in the days coming up to the party, I often make the cakes ahead of time and freeze them, them bring them out the night before, it's easier to put icing on the cake if it's cold, the cake not the icing. ITMS