    # File lib/action_controller/integration.rb, line 490
        def open_session
          session = Integration::Session.new

          # delegate the fixture accessors back to the test instance
          extras = Module.new { attr_accessor :delegate, :test_result }
          self.class.fixture_table_names.each do |table_name|
            name = table_name.tr(".", "_")
            next unless respond_to?(name)
            extras.send(:define_method, name) { |*args| delegate.send(name, *args) }
          end

          # delegate add_assertion to the test case
          extras.send(:define_method, :add_assertion) { test_result.add_assertion }
          session.extend(extras)
          session.delegate = self
          session.test_result = @_result

          yield session if block_given?
          session
        end