@Test
public void testNodeGroup() throws Exception {

  String res = cluster.getNodeGroup("");
  assertTrue("NodeGroup should be NodeBase.ROOT for empty location",
      res.equals(NodeBase.ROOT));
  try {
    cluster.getNodeGroup(null);
  } catch (IllegalArgumentException e) {
    assertTrue("Null Network Location should throw exception!",
        e.getMessage().contains("Network Location is null"));
  }
}