@Test
    void verifyAuditableOperation() {
        val c = new X509CertificateCredential(new X509Certificate[]{VALID_CERTIFICATE});
        val set = new LinkedHashSet<>();
        set.add(c);
        val json = AuditTrailManager.toJson(set);
        assertNotNull(json);
    }
This is {@link X509CertificateCredentialJsonSerializerTests}.

@author Misagh Moayyed
@since 6.4.0
support/cas-server-support-x509-core/src/test/java/org/apereo/cas/adaptors/x509/util/X509CertificateCredentialJsonSerializerTests.java