@Test
public void testAccessTokenSignedTokenConfigFile() {

    long now = System.currentTimeMillis() / 1000;
    AccessToken accessToken = createAccessToken(now);
    // now get the signed token
    PrivateKey privateKey = Crypto.loadPrivateKey(ecPrivateKey);
    String accessJws = accessToken.getSignedToken(privateKey, "eckey1", SignatureAlgorithm.ES256);
    assertNotNull(accessJws);
    // now verify our signed token
    final String oldConf = System.setProperty(JwtsSigningKeyResolver.ZTS_PROP_ATHENZ_CONF,
            "src/test/resources/athenz.conf");
    JwtsSigningKeyResolver resolver = new JwtsSigningKeyResolver(null, null);
    AccessToken checkToken = new AccessToken(accessJws, resolver);
    validateAccessToken(checkToken, now);
    if (oldConf == null) {
        System.clearProperty(JwtsSigningKeyResolver.ZTS_PROP_ATHENZ_CONF);
    } else {
        System.setProperty(JwtsSigningKeyResolver.ZTS_PROP_ATHENZ_CONF, oldConf);
    }
}