private AuthnRequest signAuthnRequest(final HttpServletRequest request,
                                          final HttpServletResponse response,
                                          final AuthnRequest authnRequest) throws Exception {
        val adaptor = SamlRegisteredServiceMetadataAdaptor
            .get(samlRegisteredServiceCachingMetadataResolver, samlRegisteredService,
                samlRegisteredService.getServiceId()).get();
        return samlIdPObjectSigner.encode(authnRequest, samlRegisteredService,
            adaptor, response, request, SAMLConstants.SAML2_POST_BINDING_URI, authnRequest, new MessageContext());
    }
This is {@link SSOSamlIdPPostProfileHandlerControllerTests}.

@author Misagh Moayyed
@since 6.2.0
support/cas-server-support-saml-idp/src/test/java/org/apereo/cas/support/saml/web/idp/profile/sso/SSOSamlIdPPostProfileHandlerControllerTests.java