# File lib/cucumber/formatter/html.rb, line 371
      def build_exception_detail(exception)
        backtrace = Array.new
        @builder.div(:class => 'message') do
          message = exception.message
          if defined?(RAILS_ROOT) && message.include?('Exception caught')
            matches = message.match(/Showing <i>(.+)<\/i>(?:.+) #(\d+)/)
            backtrace += ["#{RAILS_ROOT}/#{matches[1]}:#{matches[2]}"] if matches
            message = message.match(/<code>([^(\/)]+)<\//m)[1]
          end
          @builder.pre do 
            @builder.text!(message)
          end
        end
        @builder.div(:class => 'backtrace') do
          @builder.pre do
            backtrace = exception.backtrace
            backtrace.delete_if { |x| x =~ /\/gems\/(cucumber|rspec)/ }
            @builder << backtrace_line(backtrace.join("\n"))
          end
        end
        extra = extra_failure_content(backtrace)
        @builder << extra unless extra == ""
      end