@Test
        void verifyResolverUnknownUrl() throws Throwable {
            val resolver = getMetadataResolver();
            val service = new SamlRegisteredService();
            service.setName(RandomUtils.randomAlphabetic(12));
            service.setId(RandomUtils.nextInt());
            service.setMetadataLocation("https://this-is-unknown.com:444");
            assertTrue(resolver.resolve(service).isEmpty());
        }
This is {@link UrlResourceMetadataResolverTests}.

@author Misagh Moayyed
@since 5.3.0
support/cas-server-support-saml-idp-metadata/src/test/java/org/apereo/cas/support/saml/services/idp/metadata/cache/resolver/UrlResourceMetadataResolverTests.java