[DPE-4106] Tests legacy and modern endpoints simultaneously

[BalabaDmitri]

Issue #444
Simultaneous creation of legacy and modern endpoints relations

Solution
Charm goes into a "blocked" state, when creating a simultaneous relation legacy and modern endpoints.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.83%. Comparing base (faa360a) to head (50bf245).
Report is 9 commits behind head on main.

❗ Current head 50bf245 differs from pull request most recent head 5474507. Consider uploading reports for the commit 5474507 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #396      +/-   ##
==========================================
- Coverage   80.96%   80.83%   -0.13%     
==========================================
  Files          10       10              
  Lines        2259     2244      -15     
  Branches      363      362       -1     
==========================================
- Hits         1829     1814      -15     
- Misses        354      356       +2     
+ Partials       76       74       -2     

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[taurus-forever]

Hi @BalabaDmintri and thank you for contribution here!
Please sign contribution agreement to merge the PR: https://github.com/canonical/postgresql-operator/actions/runs/8256188989/job/22618992227?pr=396

Tl;DR: Are we testing the right things here? :-D

Long: I am slightly confused. I thought our current position is to disallow simultaneous legacy and modern interfaces: Please choose one endpoint to use. No need to relate all of them simultaneously!.
IMHO, charm should get into 'blocked' state forcing users to remove one relation and choose legacy or modern only.
@marceloneppel is it still valid position? I cannot find such blockers in charm.py code :-(

[marceloneppel]

Hi @BalabaDmintri and thank you for contribution here! Please sign contribution agreement to merge the PR: https://github.com/canonical/postgresql-operator/actions/runs/8256188989/job/22618992227?pr=396

Tl;DR: Are we testing the right things here? :-D

Long: I am slightly confused. I thought our current position is to disallow simultaneous legacy and modern interfaces: Please choose one endpoint to use. No need to relate all of them simultaneously!. IMHO, charm should get into 'blocked' state forcing users to remove one relation and choose legacy or modern only. @marceloneppel is it still valid position? I cannot find such blockers in charm.py code :-(

Hi @taurus-forever! In my opinion, we need to fix this in the relations to forbid them from being established simultaneously (and match Note: do NOT relate both modern and legacy interfaces simultaneously! from https://charmhub.io/postgresql/docs/e-interfaces). We should allow it only if we find a valid use case.

If we agree on that, I can create issues for that.

[taurus-forever]

@BalabaDmintri , can you please add the test and charm code: simultaneous legacy and modern relations should not be allowed.

[marceloneppel]

Thanks, BalabaDmintri! That's a great implementation. I left some comments to improve the code a bit.

[taurus-forever]

@BalabaDmintri can you please update PR description. It doesn't represent the content. Tnx!

[taurus-forever]

LGTM, @dragomirp consider to merge if LGTM as well. Tnx!

[taurus-forever]

nit: 2024, you can ignore it here and update the next PR.

[taurus-forever]

This charm has no updates for ages... and I would recommend to use 2 postgresql-test-app instead... but let's see how stable the current approach is.

[dragomirp]

Hi, @BalabaDmintri, please fix the error in the unit test and sync up with main.

[BalabaDmitri]

@dragomirp Can you check

[BalabaDmitri]

@dragomirp Can you run actions