@Test
    public void authorizationIdEqualsAuthenticationId() throws Exception {
        byte[] nextChallenge = saslServer
                .evaluateResponse(clientInitialResponse(USER));
        assertEquals(0, nextChallenge.length, "Next challenge is not empty");
    }
If the callback handler handles the `OAuthBearerExtensionsValidatorCallback`
 and finds an invalid extension, SaslServer should throw an authentication exception
clients/src/test/java/org/apache/kafka/common/security/oauthbearer/internals/OAuthBearerSaslServerTest.java