superset/tests/testcontainers/db_engine_specs/test_mysql.py

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"""
Tests db_engine_specs.mysql against a real MySQL instance, spun up on
demand via testcontainers. Run via .github/workflows/testcontainers.yml.

Plain MySQL itself was never covered by this suite: MariaDB and StarRocks
both reuse `MySQLEngineSpec`'s plain "mysql" dialect via mysqlclient, but
neither stands in for vanilla MySQL server's own dialect quirks.

Could not be verified locally in this environment: mysqlclient (MySQLdb)
has a pre-existing, unrelated native-library linking issue against this
machine's Homebrew-installed libmysqlclient. CI installs it via apt on
Linux, where this does not occur.
"""

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.mysql import MySQLEngineSpec
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.mysql")

from testcontainers.community.mysql import MySqlContainer  # noqa: E402

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


@pytest.fixture(scope="module")
def engine() -> Iterator[Engine]:
    with MySqlContainer("mysql:8.0") as container:
        # get_connection_url() has no host override and defaults to
        # get_container_host_ip(), which is the literal string "localhost"
        # on native Linux Docker (e.g. GitHub Actions runners). MySQLdb
        # (mysqlclient) treats a "localhost" host specially and attempts a
        # Unix socket connection instead of TCP, which fails since there's
        # no local MySQL socket -- the container is reached over the
        # network. Only rewrite that specific local case to 127.0.0.1; a
        # remote Docker daemon reports its own real host/IP here, which
        # must be preserved so the suite can still reach it.
        host = container.get_container_host_ip()
        if host == "localhost":
            host = "127.0.0.1"
        port = container.get_exposed_port(container.port)
        yield create_engine(
            f"mysql://{container.username}:{container.password}"
            f"@{host}:{port}/{container.dbname}"
        )


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:
    """
    MySQLEngineSpec.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 = MySQLEngineSpec.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 = MySQLEngineSpec.get_column_spec(str(col["type"]))
        assert spec is not None
        assert spec.generic_type == GenericDataType.NUMERIC
        assert isinstance(spec.sqla_type, Integer)