@Override
    public void registerInstance(String serviceName, String ip, int port) throws NacosException {
        registerInstance(serviceName, ip, port, Constants.DEFAULT_CLUSTER_NAME);
    }
@Test
    void testRegisterInstance7() throws NacosException {
        Throwable exception = assertThrows(NacosException.class, () -> {
            
            //given
            String serviceName = "service1";
            String groupName = "group1";
            Instance instance = new Instance();
            instance.setClusterName("cluster1,cluster2");
            //when
            client.registerInstance(serviceName, groupName, instance);
        });
        assertTrue(exception.getMessage().contains(
                "Instance 'clusterName' should be characters with only 0-9a-zA-Z-. (current: cluster1,cluster2)"));
    }