@Test
public void testFileDoesNotExist() {

  TableMapping mapping = new TableMapping();
  Configuration conf = new Configuration();
  conf.set(NET_TOPOLOGY_TABLE_MAPPING_FILE_KEY, "/this/file/does/not/exist");
  mapping.setConf(conf);
  List<String> names = new ArrayList<String>();
  names.add("a.b.c");
  names.add("1.2.3.4");
  List<String> result = mapping.resolve(names);
  assertEquals(names.size(), result.size());
  assertEquals(result.get(0), NetworkTopology.DEFAULT_RACK);
  assertEquals(result.get(1), NetworkTopology.DEFAULT_RACK);
}