anceof
          HTMLSpanElement,
        'user.age el is a span'
      );

      data.user = {};
      const nameSpan = document.querySelector('[sb-mark="user.name"]');
      const ageSpan = document.querySelector('[sb-mark="user.age"]');
      test(nameSpan instanceof HTMLSpanElement, 'user.name is a span');
      test(nameSpan.innerText === '', 'user.name span is empty');
      test(ageSpan instanceof HTMLSpanElement, 'user.age is a span');
      test(ageSpan.innerText === '', 'user.age span is empty');
