@Before public void before() { service = new DefaultOperationsServerListService(); BootstrapNode zkNode = Mockito.mock(BootstrapNode.class); OperationsNodeInfo nodeInfo = new OperationsNodeInfo(); nodeInfo.setConnectionInfo(new ConnectionInfo("localhost", 8000, ByteBuffer.wrap(new byte[0]))); List<TransportMetaData> mdList = new ArrayList<TransportMetaData>(); mdList.add( new TransportMetaData( 1, 42, 42, Collections.singletonList( new VersionConnectionInfoPair(42, ByteBuffer.wrap("test".getBytes()))))); mdList.add( new TransportMetaData( 2, 73, 73, Collections.singletonList( new VersionConnectionInfoPair(73, ByteBuffer.wrap("test".getBytes()))))); mdList.add( new TransportMetaData( 3, 1, 3, Arrays.asList( new VersionConnectionInfoPair(1, ByteBuffer.wrap("test1".getBytes())), new VersionConnectionInfoPair(2, ByteBuffer.wrap("test2".getBytes())), new VersionConnectionInfoPair(3, ByteBuffer.wrap("test3".getBytes()))))); nodeInfo.setTransports(mdList); Mockito.when(zkNode.getCurrentOperationServerNodes()).thenReturn(Arrays.asList(nodeInfo)); service.init(zkNode); }