Add test for off-chain vote data size limit

[ArturWieczorek]

Summary

Tests cardano-db-sync's off-chain vote data size limit. db-sync fetches gov-action and DRep anchors up to a fixed size (httpGetOffChainVoteDataSingle in OffChain/Http.hs, currently 3,000,000 bytes); content up to that size is downloaded and stored in off_chain_vote_data, larger content is rejected with a Size error recorded in off_chain_vote_fetch_error and no data row.

New module tests_conway/test_offchain_vote_size.py with TestOffChainVoteSize:

• test_within_size_limit — an info action with a conformant anchor of exactly OFFCHAIN_VOTE_MAX_BYTES (3,000,000); asserts db-sync stores off_chain_vote_data with is_valid = TRUE and the raw bytes match.
• test_over_size_limit — an anchor one byte over the limit; asserts db-sync records a Size error in off_chain_vote_fetch_error and stores no off_chain_vote_data row.

The anchor payloads are generated at runtime (a conformant CIP-108 document padded via body.motivation, made unique per run) and served from the internal web server, so no multi-MB fixtures are committed to the repo. A small additive helper dbsync_queries.query_voting_anchor_id(url=...) looks up the anchor id by url (used to find the fetch-error row without going through get_gov_action_proposals).

Verification

Verified end-to-end on a local dev cluster — 2 passed on db-sync 13.7.2.1 (rev db8cdf6, off-chain vote limit = 3,000,000 bytes):

2 passed in 581.65s (0:09:41)

Note

Like the other web.publish-based off-chain tests (e.g. test_drep.py::TestDReps::test_register_wrong_metadata), this test needs db-sync started with --allow-private-offchain-urls so it can fetch the anchor from the cluster's local web server; otherwise db-sync rejects the localhost url and no off_chain_vote_data / off_chain_vote_fetch_error row is produced.

Note on history

This replaces the original approach (padding the shared governance_action_anchor.json, since renamed to ga_anchor.json, to ~1 MB). That would have bloated the shared conformant anchor used by many unrelated tests and, on its own, exercised no db-sync behavior. The branch was reset to master and rebuilt as the boundary test above.

[ArturWieczorek]

CI tests: 💚

https://github.com/IntersectMBO/cardano-node-tests/actions/runs/29530385569/job/87729023887

Local tests: 💚

 WARNING: Using `cardano-cli` from custom path!
 WARNING: Using `cardano-node` from custom path!
============================= test session starts ==============================
platform linux -- Python 3.13.9, pytest-9.0.3, pluggy-1.5.0 -- /home/artur/Projects/cardano-node-tests/.venv/bin/python
hypothesis profile 'default'
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rootdir: /home/artur/Projects/cardano-node-tests
configfile: pyproject.toml
plugins: hypothesis-6.148.7, html-4.1.1, metadata-3.1.1, xdist-3.8.0, select-0.1.2, allure-pytest-2.15.2, order-1.3.0
collecting ... collected 2 items

cardano_node_tests/tests/tests_conway/test_offchain_vote_size.py::TestOffChainVoteSize::test_within_size_limit@long 
-------------------------------- live log setup --------------------------------
INFO     cardano_node_tests.tests.conftest:conftest.py:225 Changed CWD to '/home/artur/Projects/cardano-node-tests/tmp/pytest-of-artur/pytest-43'.
-------------------------------- live log call ---------------------------------
INFO     cardano_clusterlib.clusterlib_klass:clusterlib_klass.py:378 Waiting for 23.20 sec for slot no 9005.
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 3s before repeating query for the 1 time.
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 6s before repeating query for the 2 time.
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 11s before repeating query for the 3 time.
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 18s before repeating query for the 4 time.
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 27s before repeating query for the 5 time.
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 38s before repeating query for the 6 time.
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 51s before repeating query for the 7 time.
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 66s before repeating query for the 8 time.
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 83s before repeating query for the 9 time.
PASSED                                                                   [ 50%]
cardano_node_tests/tests/tests_conway/test_offchain_vote_size.py::TestOffChainVoteSize::test_over_size_limit@long 
-------------------------------- live log call ---------------------------------
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 3s before repeating query for the 1 time.
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 6s before repeating query for the 2 time.
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 11s before repeating query for the 3 time.
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 18s before repeating query for the 4 time.
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 27s before repeating query for the 5 time.
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 38s before repeating query for the 6 time.
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 51s before repeating query for the 7 time.
WARNING  cardano_node_tests.utils.dbsync_utils:dbsync_utils.py:510 Sleeping 66s before repeating query for the 8 time.
PASSED                                                                   [100%]
------------------------------ live log teardown -------------------------------
INFO     cardano_node_tests.utils.dbsync_conn:dbsync_conn.py:35 Closing connection to db-sync database dbsync0.