test-instances

name	test-instances
description	Test instance configuration and pytest flag conventions. Use when running tests, adding new test instances, or debugging CI failures involving with_instances, skip_instances, conftest, or INSTANCE_MARKS.

Test Instances

Instance definitions

Test instances are defined in tests/fixtures/instances.py. The @with_instances() decorator parametrizes tests across backends. Instance names map to pytest markers via INSTANCE_MARKS. Sub-backends are defined in conftest.py:sub_backends:

• duckdb includes parquet_backend
• s3 includes parquet_s3_backend
• ibm_db2 includes parquet_s3_backend_db2

Pytest flags

Backend selection (opt-in unless in default_options):

• --s3, --postgres, --duckdb, --mssql, --ibm_db2, --snowflake
• --ibis, --pdtransform, --polars, --dask, --prefect
• --no-postgres, --no-duckdb, --no-lock_tests (disable defaults)

Default-enabled: postgres, duckdb, polars, lock_tests.

CI matrix (from .github/workflows/tests.yml)

Job	Flags
smoke_test	(defaults)
postgres_test	--ibis --pdtransform --no-duckdb
duckdb_test	--ibis --pdtransform --no-postgres --no-lock_tests
s3_test	--s3 --ibis --pdtransform --no-duckdb --no-postgres --no-lock_tests
mssql_test	--mssql -m mssql --ibis --pdtransform --no-postgres --no-duckdb
db2_test	--ibm_db2 -m ibm_db2 --pdtransform --no-postgres --no-duckdb