private CredentialRegistration register(final Authentication authn) throws Exception {
        val registration = getCredentialRegistration(authn);
        val json = WebAuthnUtils.getObjectMapper().writeValueAsString(registration);
        assertNotNull(json);
        webAuthnCredentialRepository.addRegistrationByUsername(authn.getPrincipal().getId(), registration);
        return registration;
    }
This is {@link WebAuthnRegisteredDevicesEndpointTests}.

@author Misagh Moayyed
@since 6.3.0
support/cas-server-support-webauthn/src/test/java/org/apereo/cas/webauthn/web/WebAuthnRegisteredDevicesEndpointTests.java