fails:BigDecimal#mod_part_of_divmod returns self modulo other
fails:BigDecimal#mod_part_of_divmod returns a [Float value] when the argument is Float
fails:BigDecimal#mod_part_of_divmod returns NaN if NaN is involved
fails:BigDecimal#mod_part_of_divmod returns NaN if Infinity is involved
fails:BigDecimal#mod_part_of_divmod raises TypeError if the argument cannot be coerced to BigDecimal
fails:BigDecimal#mod_part_of_divmod does NOT raise ZeroDivisionError if other is zero
fails:BigDecimal#divmod array contains quotient and modulus as BigDecimal
fails:BigDecimal#divmod Can be reversed with * and +
fails:BigDecimal#divmod properly handles special values
fails:BigDecimal#divmod returns an array of two NaNs if the argument is zero
