superset2/tests/testcontainers/db_engine_specs/test_postgres.py

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"""
Tests db_engine_specs.postgres against a real PostgreSQL instance, spun up
on demand via testcontainers. Run via .github/workflows/testcontainers.yml
-- these exercise real SQL execution and dialect introspection, which
mocked unit tests structurally cannot.

Plain Postgres itself was never covered by this suite: CockroachDB,
TimescaleDB and YugabyteDB all speak the Postgres wire protocol and already
exercise `PostgresContainer`/the "postgresql" dialect, but none of them
stand in for vanilla PostgreSQL's own dialect quirks.
"""

from collections.abc import Iterator

import pytest
from sqlalchemy import (
    Column,
    create_engine,
    inspect,
    Integer,
    MetaData,
    Table as SATable,
)
from sqlalchemy.engine import Engine

from superset.db_engine_specs.postgres import PostgresEngineSpec
from superset.sql.parse import Table
from superset.utils.core import GenericDataType

pytestmark = pytest.mark.testcontainers

from ._driver import require_driver  # noqa: E402

require_driver("testcontainers.community.postgres")

from testcontainers.community.postgres import PostgresContainer  # noqa: E402

from ._pagination import (  # noqa: E402
    assert_paginated_query_returns_correct_rows_in_order,
)


@pytest.fixture(scope="module")
def engine() -> Iterator[Engine]:
    with PostgresContainer("postgres:17-alpine") as container:
        yield create_engine(container.get_connection_url())


def test_paginated_query_returns_correct_rows_in_order(engine: Engine) -> None:
    """
    A plain SQLAlchemy Core LIMIT/OFFSET query, compiled and executed against
    a real instance. Mocked tests cannot catch a dialect compiling this
    incorrectly (see apache/superset#42899, where Trino emitted OFFSET
    before LIMIT) -- only real execution can.
    """
    assert_paginated_query_returns_correct_rows_in_order(engine)


def test_get_columns_maps_native_types(engine: Engine) -> None:
    """
    PostgresEngineSpec.get_columns wraps a real SQLAlchemy Inspector; this
    exercises that against actual server-reported column metadata rather
    than a mocked Inspector.
    """
    metadata = MetaData()
    SATable(
        "pilot_types",
        metadata,
        Column("id", Integer, primary_key=True),
        Column("amount", Integer),
    )
    metadata.create_all(engine)

    inspector = inspect(engine)
    columns = PostgresEngineSpec.get_columns(inspector, Table("pilot_types"))

    by_name = {col["column_name"]: col for col in columns}
    assert set(by_name) == {"id", "amount"}
    for col in by_name.values():
        spec = PostgresEngineSpec.get_column_spec(str(col["type"]))
        assert spec is not None
        assert spec.generic_type == GenericDataType.NUMERIC
        assert isinstance(spec.sqla_type, Integer)