全然覚えられないのでここに書いたということだけ覚えましょう
## 何も指定しないと1回です # 1回 double.should_receive(:msg).once # 2回 double.should_receive(:msg).twice # n回 double.should_receive(:msg).exactly(n).times # 最低1回 double.should_receive(:msg).at_least(:once) # 最低2回 double.should_receive(:msg).at_least(:twice) # 最低n回 double.should_receive(:msg).at_least(n).times # 最高1回 double.should_receive(:msg).at_most(:once) # 最高2回 double.should_receive(:msg).at_most(:twice) # 最高n回 double.should_receive(:msg).at_most(n).times # 何回でも double.should_receive(:msg).any_number_of_times