# File actionpack/lib/action_controller/assertions/selector_assertions.rb, line 180
      def assert_select(*args, &block)
        # Start with optional element followed by mandatory selector.
        arg = args.shift

        if arg.is_a?(HTML::Node)
          # First argument is a node (tag or text, but also HTML root),
          # so we know what we're selecting from.
          root = arg
          arg = args.shift
        elsif arg == nil
          # This usually happens when passing a node/element that
          # happens to be nil.
          raise ArgumentError, "First argument is either selector or element to select, but nil found. Perhaps you called assert_select with an element that does not exist?"
        elsif @selected
          root = HTML::Node.new(nil)
          root.children.concat @selected
        else
          # Otherwise just operate on the response document.
          root = response_from_page_or_rjs
        end
        
        # First or second argument is the selector: string and we pass
        # all remaining arguments. Array and we pass the argument. Also
        # accepts selector itself.
        case arg
          when String
            selector = HTML::Selector.new(arg, args)
          when Array
            selector = HTML::Selector.new(*arg)
          when HTML::Selector
            selector = arg
          else raise ArgumentError, "Expecting a selector as the first argument"
        end
        
        # Next argument is used for equality tests.
        equals = {}
        case arg = args.shift
          when Hash
            equals = arg
          when String, Regexp
            equals[:text] = arg
          when Integer
            equals[:count] = arg
          when Range
            equals[:minimum] = arg.begin
            equals[:maximum] = arg.end
          when FalseClass
            equals[:count] = 0
          when NilClass, TrueClass
            equals[:minimum] = 1
          else raise ArgumentError, "I don't understand what you're trying to match"
        end

        # By default we're looking for at least one match.
        if equals[:count]
          equals[:minimum] = equals[:maximum] = equals[:count]
        else
          equals[:minimum] = 1 unless equals[:minimum]
        end

        # Last argument is the message we use if the assertion fails.
        message = args.shift
        #- message = "No match made with selector #{selector.inspect}" unless message
        if args.shift
          raise ArgumentError, "Not expecting that last argument, you either have too many arguments, or they're the wrong type"
        end

        matches = selector.select(root)
        # If text/html, narrow down to those elements that match it.
        content_mismatch = nil
        if match_with = equals[:text]
          matches.delete_if do |match|
            text = ""
            stack = match.children.reverse
            while node = stack.pop
              if node.tag?
                stack.concat node.children.reverse
              else
                text << node.content
              end
            end
            text.strip! unless NO_STRIP.include?(match.name)
            unless match_with.is_a?(Regexp) ? (text =~ match_with) : (text == match_with.to_s)
              content_mismatch ||= build_message(message, "<?> expected but was\n<?>.", match_with, text)
              true
            end
          end
        elsif match_with = equals[:html]
          matches.delete_if do |match|
            html = match.children.map(&:to_s).join
            html.strip! unless NO_STRIP.include?(match.name)
            unless match_with.is_a?(Regexp) ? (html =~ match_with) : (html == match_with.to_s)
              content_mismatch ||= build_message(message, "<?> expected but was\n<?>.", match_with, html)
              true
            end
          end
        end
        # Expecting foo found bar element only if found zero, not if
        # found one but expecting two.
        message ||= content_mismatch if matches.empty?
        # Test minimum/maximum occurrence.
        min, max = equals[:minimum], equals[:maximum]
        message = message || %(Expected #{count_description(min, max)} matching "#{selector.to_s}", found #{matches.size}.)
        assert matches.size >= min, message if min
        assert matches.size <= max, message if max

        # If a block is given call that block. Set @selected to allow
        # nested assert_select, which can be nested several levels deep.
        if block_given? && !matches.empty?
          begin
            in_scope, @selected = @selected, matches
            yield matches
          ensure
            @selected = in_scope
          end
        end

        # Returns all matches elements.
        matches
      end

# File actionpack/lib/action_controller/assertions/selector_assertions.rb, line 525
      def assert_select_email(&block)
        deliveries = ActionMailer::Base.deliveries
        assert !deliveries.empty?, "No e-mail in delivery list"

        for delivery in deliveries
          for part in delivery.parts
            if part["Content-Type"].to_s =~ /^text\/html\W/
              root = HTML::Document.new(part.body).root
              assert_select root, ":root", &block
            end
          end
        end
      end

# File actionpack/lib/action_controller/assertions/selector_assertions.rb, line 479
      def assert_select_encoded(element = nil, &block)
        case element
          when Array
            elements = element
          when HTML::Node
            elements = [element]
          when nil
            unless elements = @selected
              raise ArgumentError, "First argument is optional, but must be called from a nested assert_select"
            end
          else
            raise ArgumentError, "Argument is optional, and may be node or array of nodes"
        end

        fix_content = lambda do |node|
          # Gets around a bug in the Rails 1.1 HTML parser.
          node.content.gsub(/<!\[CDATA\[(.*)(\]\]>)?/m) { CGI.escapeHTML($1) }
        end

        selected = elements.map do |element|
          text = element.children.select{ |c| not c.tag? }.map{ |c| fix_content[c] }.join
          root = HTML::Document.new(CGI.unescapeHTML("<encoded>#{text}</encoded>")).root
          css_select(root, "encoded:root", &block)[0]
        end

        begin
          old_selected, @selected = @selected, selected
          assert_select ":root", &block
        ensure
          @selected = old_selected
        end
      end

# File actionpack/lib/action_controller/assertions/selector_assertions.rb, line 382
      def assert_select_rjs(*args, &block)
        rjs_type = nil
        arg      = args.shift

        # If the first argument is a symbol, it's the type of RJS statement we're looking
        # for (update, replace, insertion, etc). Otherwise, we're looking for just about
        # any RJS statement.
        if arg.is_a?(Symbol)
          rjs_type = arg

          if rjs_type == :insert
            arg = args.shift
            insertion = "insert_#{arg}".to_sym
            raise ArgumentError, "Unknown RJS insertion type #{arg}" unless RJS_STATEMENTS[insertion]
            statement = "(#{RJS_STATEMENTS[insertion]})"
          else
            raise ArgumentError, "Unknown RJS statement type #{rjs_type}" unless RJS_STATEMENTS[rjs_type]
            statement = "(#{RJS_STATEMENTS[rjs_type]})"
          end
          arg = args.shift
        else
          statement = "#{RJS_STATEMENTS[:any]}"
        end

        # Next argument we're looking for is the element identifier. If missing, we pick
        # any element.
        if arg.is_a?(String)
          id = Regexp.quote(arg)
          arg = args.shift
        else
          id = "[^\"]*"
        end

        pattern =
          case rjs_type
            when :chained_replace, :chained_replace_html
              Regexp.new("\\$\\(\"#{id}\"\\)#{statement}\\(#{RJS_PATTERN_HTML}\\)", Regexp::MULTILINE)
            when :remove, :show, :hide, :toggle
              Regexp.new("#{statement}\\(\"#{id}\"\\)")
            else
              Regexp.new("#{statement}\\(\"#{id}\", #{RJS_PATTERN_HTML}\\)", Regexp::MULTILINE)
          end

        # Duplicate the body since the next step involves destroying it.
        matches = nil
        case rjs_type
          when :remove, :show, :hide, :toggle
            matches = @response.body.match(pattern)
          else
            @response.body.gsub(pattern) do |match|
              html = unescape_rjs($2)
              matches ||= []
              matches.concat HTML::Document.new(html).root.children.select { |n| n.tag? }
              ""
            end
        end

        if matches
          if block_given? && !([:remove, :show, :hide, :toggle].include? rjs_type)
            begin
              in_scope, @selected = @selected, matches
              yield matches
            ensure
              @selected = in_scope
            end
          end
          matches
        else
          # RJS statement not found.
          flunk args.shift || "No RJS statement that replaces or inserts HTML content."
        end
      end

# File actionpack/lib/action_controller/assertions/selector_assertions.rb, line 58
      def css_select(*args)
        # See assert_select to understand what's going on here.
        arg = args.shift

        if arg.is_a?(HTML::Node)
          root = arg
          arg = args.shift
        elsif arg == nil
          raise ArgumentError, "First argument is either selector or element to select, but nil found. Perhaps you called assert_select with an element that does not exist?"
        elsif @selected
          matches = []

          @selected.each do |selected|
            subset = css_select(selected, HTML::Selector.new(arg.dup, args.dup))
            subset.each do |match|
              matches << match unless matches.any? { |m| m.equal?(match) }
            end
          end

          return matches
        else
          root = response_from_page_or_rjs
        end

        case arg
          when String
            selector = HTML::Selector.new(arg, args)
          when Array
            selector = HTML::Selector.new(*arg)
          when HTML::Selector
            selector = arg
          else raise ArgumentError, "Expecting a selector as the first argument"
        end

        selector.select(root)
      end

# File actionpack/lib/action_controller/assertions/selector_assertions.rb, line 567
        def response_from_page_or_rjs()
          content_type = @response.content_type

          if content_type && content_type =~ /text\/javascript/
            body = @response.body.dup
            root = HTML::Node.new(nil)

            while true
              next if body.sub!(RJS_PATTERN_EVERYTHING) do |match|
                html = unescape_rjs($3)
                matches = HTML::Document.new(html).root.children.select { |n| n.tag? }
                root.children.concat matches
                ""
              end
              break
            end

            root
          else
            html_document.root
          end
        end

# File actionpack/lib/action_controller/assertions/selector_assertions.rb, line 591
        def unescape_rjs(rjs_string)
          # RJS encodes double quotes and line breaks.
          unescaped= rjs_string.gsub('\"', '"')
          unescaped.gsub!('\n', "\n")
          unescaped.gsub!('\076', '>')
          unescaped.gsub!('\074', '<')
          # RJS encodes non-ascii characters.
          unescaped.gsub!(RJS_PATTERN_UNICODE_ESCAPED_CHAR) {|u| [$1.hex].pack('U*')}
          unescaped
        end