# File lib/rails/dom/testing/assertions/selector_assertions.rb, line 59
        def css_select(*args)
          raise ArgumentError, "you at least need a selector argument" if args.empty?

          root = args.size == 1 ? document_root_element : args.shift

          nodeset(root).css(args.first)
        rescue Nokogiri::CSS::SyntaxError => e
          ActiveSupport::Deprecation.warn("The assertion was not run because of an invalid css selector.\n#{e}", caller(2))
          return
        end