register_at_exit_hook

# File lib/spec/runner.rb, line 44
      def register_at_exit_hook # :nodoc:
        unless @already_registered_at_exit_hook
          at_exit do
            unless $! || run? || Spec::Example::ExampleGroupFactory.registered_or_ancestor_of_registered?(options.example_groups)
              success = run
              exit success if exit?
            end
          end
          @already_registered_at_exit_hook = true
        end
      end