@Override
            public List<Credential> fromAuthentication(final HttpServletRequest request,
                                                       final MultiValueMap<String, String> requestBody,
                                                       final Authentication authentication,
                                                       final MultifactorAuthenticationProvider provider) {
                if (provider.getId().contains("unknown")) {
                    return List.of();
                }
                return List.of(new UsernamePasswordCredential("mfa-user", "mfa-user"));
            }
This is {@link UserAuthenticationResourceTests}.

@author Misagh Moayyed
@since 5.3.0
support/cas-server-support-rest/src/test/java/org/apereo/cas/support/rest/UserAuthenticationResourceTests.java