public void RollIsOutOfRange() { var roller = new DiceRoller(); //Test if max is less than 0. roller.Invoking(f => f.Roll(-1)).ShouldThrow <ArgumentOutOfRangeException>(); //Test if min is less than 0. roller.Invoking(f => f.Roll(100, -1)).ShouldThrow <ArgumentOutOfRangeException>(); //Test if max is less than min. (Default min is 1). roller.Invoking(f => f.Roll(1, 5)).ShouldThrow <ArgumentOutOfRangeException>(); }