Github user zentol commented on the issue:
The end-to-end test would be cheap as we wouldn't execute a flink job or
even start a flink cluster.
The scripts in `flink-end-to-end-tests` can do pretty much anything they
want; my idea was to just call the test method in a non-test context, in which
case the test should throw an AssertionError. It may not be the cleanest thing
to do though as we have to max test and production code in a single jar.
My goal was to verify that the sections guarded by
`CONCURRENT_ACCESS_CHECK` are skipped at runtime by default. As it stands
someone could just hard-code it to `true` and there's no test preventing that.