code: def exact_child_name_under(path)
        path = path[1,path.length-1] if !!(path =~ /^#{ChefFS::PathUtils::regexp_path_separator}/)
        dirs_in_path = ChefFS::PathUtils::split(path).length
        return nil if exact_parts.length <= dirs_in_path
        return exact_parts[dirs_in_path]
      end
docs: Returns the immediate child of a path that would be matched
   if this FilePattern was applied.  If more than one child
   could match, this method returns nil.
  
   ==== Attributes
  
   * +path+ - The path to look for an exact child name under.
  
   ==== Returns
  
   The next directory in the pattern under the given path.
   If the directory part could match more than one child, it
   returns +nil+.
  
   ==== Examples
  
     abc/def.exact_child_name_under('abc') == 'def'
     abc/def/ghi.exact_child_name_under('abc') == 'def'
     abc/*/ghi.exact_child_name_under('abc') == nil
     abc/*/ghi.exact_child_name_under('abc/def') == 'ghi'
     abc/**/ghi.exact_child_name_under('abc/def') == nil
  
   This method assumes +could_match_children?(path)+ is +true+.