@Test
        void verifyAuthenticationWithoutResolvedPrincipal() {
            val credentials = new UsernamePasswordCredentials("serviceWithAttributesMapping", "secret");

            val registeredService = new OAuthRegisteredService();
            registeredService.setClientId(credentials.getUsername());
            registeredService.setName(UUID.randomUUID().toString());
            registeredService.setServiceId(CoreAuthenticationTestUtils.CONST_TEST_URL);
            servicesManager.save(registeredService);

            val request = new MockHttpServletRequest();
            val ctx = new JEEContext(request, new MockHttpServletResponse());
            oauthClientAuthenticator.validate(new CallContext(ctx, new JEESessionStore()), credentials);
            assertNotNull(credentials.getUserProfile());
            assertEquals(credentials.getUsername(), credentials.getUserProfile().getId());
        }
This is {@link OAuth20ClientIdClientSecretAuthenticatorTests}.

@author Misagh Moayyed
@since 6.0.0
support/cas-server-support-oauth/src/test/java/org/apereo/cas/support/oauth/authenticator/OAuth20ClientIdClientSecretAuthenticatorTests.java