@Override
        public Long apply(List<ApiMessageAndVersion> apiMessageAndVersions) {
            for (ApiMessageAndVersion apiMessageAndVersion : apiMessageAndVersions) {
                BrokerRegistrationChangeRecord record =
                        (BrokerRegistrationChangeRecord) apiMessageAndVersion.message();
                assertEquals((int) offset, record.brokerId());
                offset++;
            }
            return offset;
        }
Test that certain controller operations finish immediately without putting an event
on the controller queue, if there is nothing to do.
metadata/src/test/java/org/apache/kafka/controller/QuorumControllerTest.java