@Test
public void testGetSocketFactory() {

    final String oldConf = System.setProperty(JwtsSigningKeyResolver.ZTS_PROP_ATHENZ_CONF,
            "src/test/resources/athenz.conf");
    JwtsSigningKeyResolver resolver = new JwtsSigningKeyResolver(null, null);
    assertNull(resolver.getSocketFactory(null));
    if (oldConf == null) {
        System.clearProperty(JwtsSigningKeyResolver.ZTS_PROP_ATHENZ_CONF);
    } else {
        System.setProperty(JwtsSigningKeyResolver.ZTS_PROP_ATHENZ_CONF, oldConf);
    }
}