@Test
public void testExtractX509CertIpAddressesSingle() throws Exception {

    try (InputStream inStream = new FileInputStream("src/test/resources/x509_altnames_singleip.cert")) {
        CertificateFactory cf = CertificateFactory.getInstance("X.509");
        X509Certificate cert = (X509Certificate) cf.generateCertificate(inStream);
        List<String> ips = Crypto.extractX509CertIPAddresses(cert);
        assertEquals(1, ips.size());
        assertEquals(ips.get(0), "10.11.12.13");
    }
}