assertTrue(result.contains("contentSize=0"));
        assertTrue(result.contains("processingTime=0"));
        assertTrue(result.contains("elementData=[]"));
    }

    public void test_toString_with_data() {
        DocList docList = new DocList();

        Map<String, Object> doc = new HashMap<>();
        doc.put("id", "1");
        docList.add(doc);

        docList.addContentSize(1000);