To be fair, in WW2 Germany did not attack France - it attacked Poland, and expected that France would not keep its alliance and give it up just as they folded o

To be fair, in WW2 Germany did not attack France - it attacked Poland, and expected that France would not keep its alliance and give it up just as they folded on Sudatenland and the rest of Czechoslovakia, but France did attack Germany over that; and arguably if the German expectations about French/British reaction turned out to be true, then annexing Poland would be in their best interest according to what was beneficial for states in early 20th century (now the economic incentives have substantially changed).