fails:Rational#round with no arguments (precision = 0) returns an integer
fails:Rational#round with no arguments (precision = 0) returns the truncated value toward the nearest integer
fails:Rational#round with a precision < 0 returns an integer
fails:Rational#round with a precision < 0 moves the truncation point n decimal places left
fails:Rational#round with a precision > 0 returns a Rational
fails:Rational#round with a precision > 0 moves the truncation point n decimal places right
fails:Rational#round with a precision > 0 doesn't alter the value if the precision is too great
fails:Rational#round with a precision > 0 doesn't fail when rounding to an absurdly large positive precision
