t element = document.createElement(element_name);
        t.add_cleanup(() => element.remove());
        document.body.append(element);
        await Promise.resolve();
        reactions = [];
        document.getElementById("section").moveBefore(element, null);
        await Promise.resolve();
        assert_array_equals(reactions, ["connected"]);
    }, "When disconnectedCallback is not defined, no crash");
</script>
</body>
