@Test
        void verifyEchoingOperation() {
            val registeredService = getOidcRegisteredService();
            val oidcService = OidcIssuerService.echoing("https://custom.issuer/");
            assertEquals("https://custom.issuer/", oidcService.determineIssuer(Optional.empty()));
            assertEquals("https://custom.issuer/", oidcService.determineIssuer(Optional.of(registeredService)));

            val request = new MockHttpServletRequest();
            val response = new MockHttpServletResponse();
            val context = new JEEContext(request, response);
            assertTrue(oidcService.validateIssuer(context, List.of(OidcConstants.CLIENT_CONFIGURATION_URL)));
        }
This is {@link OidcDefaultIssuerServiceTests}.

@author Misagh Moayyed
@since 6.4.0
support/cas-server-support-oidc/src/test/java/org/apereo/cas/oidc/issuer/OidcDefaultIssuerServiceTests.java