Object result = data.getDataMap().get("complex");
        assertEquals(obj, result); // Non-entity objects are registered as-is
    }

    @Test
    public void test_register_arrayList() {
        RenderData data = new RenderData();

        BsUser entity1 = new BsUser();
        entity1.setName("user1");

        // Test ArrayList specifically (not just List interface)