How to unit test JNI Methods

I've been trying to expose some c++ native method in Rocksdb to the Java API. I got lost when it comes to testing the JNI code. I've searched a lot on the internet but didn't find much information in this regard. I've also looked a lot in the Rocksdb source code, but didn't find anything about how the other JNI Methods are unit-tested. Posted my question to the Rocksdb team on Google Groups here and got no answer yet.

Any help will be greatly appreciated.