def testOpenTypes(self):
        substrate = pem.readBase64fromText(self.cert_pem_text)
        asn1Object, rest = der_decoder(
            substrate, asn1Spec=self.asn1Spec, decodeOpenTypes=True)

        self.assertFalse(rest)
        self.assertTrue(asn1Object.prettyPrint())
        self.assertEqual(substrate, der_encoder(asn1Object))

        perm_id_oid = rfc4043.id_on_permanentIdentifier
        assigner_oid = univ.ObjectIdentifier('1.3.6.1.4.1.22112.48')
        permanent_identifier_found = False

        for extn in asn1Object['tbsCertificate']['extensions']:
            if extn['extnID'] == rfc5280.id_ce_subjectAltName:
                extnValue, rest = der_decoder(
                    extn['extnValue'], asn1Spec=rfc5280.SubjectAltName(),
                    decodeOpenTypes=True)

                self.assertFalse(rest)
                self.assertTrue(extnValue.prettyPrint())
                self.assertEqual(extn['extnValue'], der_encoder(extnValue))

                for gn in extnValue:
                    if gn['otherName'].hasValue():
                        on = gn['otherName']
                        self.assertEqual(perm_id_oid, on['type-id'])
                        self.assertEqual(assigner_oid, on['value']['assigner'])
                        permanent_identifier_found = True

        self.assertTrue(permanent_identifier_found)