@Test
public void testNonExistSslClientXml() throws Exception{

  Configuration conf = new Configuration(false);
  conf.setBoolean(SSL_REQUIRE_CLIENT_CERT_KEY, false);
  conf.set(SSL_CLIENT_CONF_KEY, "non-exist-ssl-client.xml");
  Configuration sslConf =
      SSLFactory.readSSLConfiguration(conf, SSLFactory.Mode.CLIENT);
  assertNull(sslConf.getResource("non-exist-ssl-client.xml"));
  assertNull(sslConf.get("ssl.client.truststore.location"));
}