class Test::Unit::CodeSnippetFetcher

def detect_encoding(first_line)
  return nil unless first_line.respond_to?(:ascii_only?)
  return nil unless first_line.ascii_only?
  if /\b(?:en)?coding[:=]\s*([a-z\d_-]+)/i =~ first_line
    begin
      Encoding.find($1)
    rescue ArgumentError
      nil
    end
  else
    nil
  end
end