public void setNodes(String clusterName, String group, List<Node> nodes) {
        this.clusterNodes.computeIfAbsent(clusterName, k -> new ConcurrentHashMap<>()).put(group, nodes);
    }
@Test
    public void testSetNodes() {
        Assertions.assertDoesNotThrow(() -> metadata.setNodes("cluster", "group", new ArrayList<>()));
    }