@Test
    void verifyBadOperation() throws Throwable {
        val service = addRegisteredService();
        val request = new MockHttpServletRequest();
        val response = new MockHttpServletResponse();
        val auth = service.getClientId() + ':' + CLIENT_SECRET;
        val value = EncodingUtils.encodeBase64(auth.getBytes(StandardCharsets.UTF_8));
        request.addHeader(HttpConstants.AUTHORIZATION_HEADER, HttpConstants.BASIC_HEADER_PREFIX + value);
        val result = introspectionEndpoint.handleRequest(request, response);
        assertEquals(HttpStatus.BAD_REQUEST, result.getStatusCode());
    }
This is {@link OAuth20IntrospectionEndpointControllerTests}.

@author Misagh Moayyed
@since 6.1.0
support/cas-server-support-oauth/src/test/java/org/apereo/cas/support/oauth/web/endpoints/OAuth20IntrospectionEndpointControllerTests.java