register_at_exit_hook

# File lib/spec/runner.rb, line 187
      def register_at_exit_hook # :nodoc:
        $spec_runner_at_exit_hook_registered ||= nil
        unless $spec_runner_at_exit_hook_registered
          at_exit do
            unless $! || Spec.run?; \
              success = Spec.run; \
              exit success if Spec.exit?; \
            end
          end
          $spec_runner_at_exit_hook_registered = true
        end
      end