Add AES GCM streaming encryption test cases

[xanderbailey]

Change

New test surface

Spec reference

https://iceberg.apache.org/gcm-stream-spec/

Description

As we continue to implement the encryption spec across different languages it would be very valuable to have shared test artefacts for streaming encryption.

Came up here apache/iceberg-python#3969 in a conversation with @mbutrovich

[sungwy]

Thanks for raising this @xanderbailey - this sounds like a good candidate for the repository. Would you be interested in making this contribution following https://github.com/apache/iceberg-verification/blob/main/CONTRIBUTING.md ?

[xanderbailey]

100% happy to add this

[sungwy]

Awesome. Assigned this to you @xanderbailey

I think this can stay at the top level, parallel to table-spec which is proposed in this PR: https://github.com/apache/iceberg-verification/pull/3/changes

[xanderbailey]

Noting that we will have to contend with apache/iceberg#18219 as we work on this contribution

[xanderbailey]

Just started working on this, one question I have since we don't have a lot of precedence here is should I checkin the implementation in Java for how the test cases are generated? Or just checkin the json?

[sungwy]

Noting that we will have to contend with apache/iceberg#18219 as we work on this contribution

That's a fantastic note @xanderbailey - it'll be awesome to record the resolved and expected fixture here for the contended case.

Just started working on this, one question I have since we don't have a lot of precedence here is should I checkin the implementation in Java for how the test cases are generated? Or just checkin the json?

I think just checking in the json, and then explaining the provenance (e.g. written by Java x.y.z see this example) with as much detail as you think is needed for these will do.