public void setSelector(String selector) {
        this.selector = selector;
    }
@Test
    void testSerialize() throws JsonProcessingException {
        ServiceListRequest request = new ServiceListRequest(NAMESPACE, GROUP, 1, 10);
        request.setSelector("label");
        String json = mapper.writeValueAsString(request);
        assertTrue(json.contains("\"groupName\":\"" + GROUP + "\""));
        assertTrue(json.contains("\"namespace\":\"" + NAMESPACE + "\""));
        assertTrue(json.contains("\"module\":\"" + NAMING_MODULE + "\""));
        assertTrue(json.contains("\"selector\":\"label\""));
        assertTrue(json.contains("\"pageNo\":1"));
        assertTrue(json.contains("\"pageSize\":10"));
    }