@Test(expected = IllegalArgumentException.class)
public void testProxyProviderNotSpecified()  throws IllegalArgumentException {

  Map<String, String> configs = new HashMap<String, String>();
  configs.put("username", "hdfsuser");
  configs.put("password", "hdfsuser");
  configs.put("hadoop.security.authentication", "simple");
  configs.put("fs.default.name", "hdfs://hwqe-1425428405");
  configs.put("dfs.nameservices", "hwqe-1425428405");
  HdfsClient.validateConnectionConfigs(configs);
}