fails:String#rpartition with String returns an array of substrings based on splitting on the given string
fails:String#rpartition with String always returns 3 elements
fails:String#rpartition with String accepts regexp
fails:String#rpartition with String affects $~
fails:String#rpartition with String converts its argument using :to_str
fails:String#rpartition with String raises an error if not convertible to string
