### Question:
VppNodeListener extends DataTreeChangeHandler<RendererNode> { private void writeData(RendererNode rendererNode) { NodeKey nodeKey = rendererNode.getNodePath().firstKeyOf(Node.class); WriteTransaction wTx = dataProvider.newWriteOnlyTransaction(); Hostconfig hcData = HostconfigUtil.createHostconfigsDataFor(nodeKey.getNodeId(), socketInfo); wTx.put(LogicalDatastoreType.OPERATIONAL, hostconfigIid(nodeKey.getNodeId()), hcData); DataStoreHelper.submitToDs(wTx); LOG.info("Hostconfig data written to DS for VPP node {}", nodeKey); } VppNodeListener(DataBroker dataBroker, SocketInfo socketInfo);  static final RendererName VPP_RENDERER_NAME; }### Answer:
@Test public void writeDataTest() throws InterruptedException, ExecutionException { assertTrue(readHostconfig(nodeId).isPresent()); }