headers_match?

# File activeresource/lib/active_resource/http_mock.rb, line 242
    def headers_match?(req)
      # Ignore format header on equality if it's not defined
      format_header = ActiveResource::Connection::HTTP_FORMAT_HEADER_NAMES[method]
      if headers[format_header].present? || req.headers[format_header].blank?
        headers == req.headers
      else
        headers.dup.merge(format_header => req.headers[format_header]) == req.headers
      end
    end