private int getNodeId() {
        int nodeId = getNodeId(System.nanoTime());
        assert nodeId > 0 || nodeId == NODE_ID_OUT_OF_RANGE : "getNodeId() returned invalid value: " + nodeId;
        return nodeId;
    }
@Test
    public void test_positiveNodeIdOffset() {
        int nodeIdOffset = 5;
        int memberListJoinVersion = 20;
        initialize(new FlakeIdGeneratorConfig().setNodeIdOffset(nodeIdOffset));

        when(clusterService.getMemberListJoinVersion()).thenReturn(memberListJoinVersion);
        assertEquals((memberListJoinVersion + nodeIdOffset), gen.getNodeId(0));
    }