make the sqlite test db setup a fixture

py-polars/tests/unit/io/test_database_read.py

@@ -9,19 +9,17 @@
 from types import GeneratorType
 from typing import TYPE_CHECKING, Any, NamedTuple
 
-import pytest
-from sqlalchemy import Integer, MetaData, Table, create_engine, func, select
-from sqlalchemy.orm import sessionmaker
-from sqlalchemy.sql.expression import cast as alchemy_cast
-
 import polars as pl
+import pytest
 from polars.exceptions import UnsuitableSQLError
 from polars.io.database import _ARROW_DRIVER_REGISTRY_
 from polars.testing import assert_frame_equal
+from sqlalchemy import Integer, MetaData, Table, create_engine, func, select
+from sqlalchemy.orm import sessionmaker
+from sqlalchemy.sql.expression import cast as alchemy_cast
 
 if TYPE_CHECKING:
     import pyarrow as pa
-
     from polars.type_aliases import (
         ConnectionOrCursor,
         DbReadEngine,
@@ -34,24 +32,26 @@ def adbc_sqlite_connect(*args: Any, **kwargs: Any) -> Any:
     with suppress(ModuleNotFoundError):  # not available on 3.8/windows
         from adbc_driver_sqlite.dbapi import connect
 
+        args = [str(a) if isinstance(a, Path) else a for a in args]
         return connect(*args, **kwargs)
 
 
-def create_temp_sqlite_db(test_db: str) -> None:
-    Path(test_db).unlink(missing_ok=True)
+@pytest.fixture()
+def tmp_sqlite_db(tmp_path: Path) -> Path:
+    test_db = tmp_path / "test.db"
+    test_db.unlink(missing_ok=True)
 
     def convert_date(val: bytes) -> date:
         """Convert ISO 8601 date to datetime.date object."""
         return date.fromisoformat(val.decode())
 
-    sqlite3.register_converter("date", convert_date)
-
     # NOTE: at the time of writing adcb/connectorx have weak SQLite support (poor or
     # no bool/date/datetime dtypes, for example) and there is a bug in connectorx that
     # causes float rounding < py 3.11, hence we are only testing/storing simple values
     # in this test db for now. as support improves, we can add/test additional dtypes).
-
+    sqlite3.register_converter("date", convert_date)
     conn = sqlite3.connect(test_db)
+
     # ┌─────┬───────┬───────┬────────────┐
     # │ id  ┆ name  ┆ value ┆ date       │
     # │ --- ┆ ---   ┆ ---   ┆ ---        │
@@ -62,17 +62,19 @@ def convert_date(val: bytes) -> date:
     # └─────┴───────┴───────┴────────────┘
     conn.executescript(
         """
-        CREATE TABLE test_data (
+        CREATE TABLE IF NOT EXISTS test_data (
             id    INTEGER PRIMARY KEY,
             name  TEXT NOT NULL,
             value FLOAT,
             date  DATE
         );
-        INSERT INTO test_data(name,value,date)
-        VALUES ('misc',100.0,'2020-01-01'), ('other',-99.5,'2021-12-31');
+        REPLACE INTO test_data(name,value,date)
+          VALUES ('misc',100.0,'2020-01-01'),
+                 ('other',-99.5,'2021-12-31');
         """
     )
     conn.close()
+    return test_db
 
 
 class DatabaseReadTestParams(NamedTuple):
@@ -314,22 +316,19 @@ def test_read_database(
     schema_overrides: SchemaDict | None,
     batch_size: int | None,
     tmp_path: Path,
+    tmp_sqlite_db: Path,
 ) -> None:
-    tmp_path.mkdir(exist_ok=True)
-    test_db = str(tmp_path / "test.db")
-    create_temp_sqlite_db(test_db)
-
     if read_method == "read_database_uri":
         # instantiate the connection ourselves, using connectorx/adbc
         df = pl.read_database_uri(
-            uri=f"sqlite:///{test_db}",
+            uri=f"sqlite:///{tmp_sqlite_db}",
             query="SELECT * FROM test_data",
             engine=str(connect_using),  # type: ignore[arg-type]
             schema_overrides=schema_overrides,
         )
     elif "adbc" in os.environ["PYTEST_CURRENT_TEST"]:
         # externally instantiated adbc connections
-        with connect_using(test_db) as conn, conn.cursor():
+        with connect_using(tmp_sqlite_db) as conn, conn.cursor():
             df = pl.read_database(
                 connection=conn,
                 query="SELECT * FROM test_data",
@@ -339,7 +338,7 @@ def test_read_database(
     else:
         # other user-supplied connections
         df = pl.read_database(
-            connection=connect_using(test_db),
+            connection=connect_using(tmp_sqlite_db),
             query="SELECT * FROM test_data WHERE name NOT LIKE '%polars%'",
             schema_overrides=schema_overrides,
             batch_size=batch_size,
@@ -350,13 +349,9 @@ def test_read_database(
     assert df["date"].to_list() == expected_dates
 
 
-def test_read_database_alchemy_selectable(tmp_path: Path) -> None:
-    # setup underlying test data
-    tmp_path.mkdir(exist_ok=True)
-    create_temp_sqlite_db(test_db := str(tmp_path / "test.db"))
-
+def test_read_database_alchemy_selectable(tmp_path: Path, tmp_sqlite_db: Path) -> None:
     # various flavours of alchemy connection
-    alchemy_engine = create_engine(f"sqlite:///{test_db}")
+    alchemy_engine = create_engine(f"sqlite:///{tmp_sqlite_db}")
     alchemy_session: ConnectionOrCursor = sessionmaker(bind=alchemy_engine)()
     alchemy_conn: ConnectionOrCursor = alchemy_engine.connect()
 
@@ -376,18 +371,14 @@ def test_read_database_alchemy_selectable(tmp_path: Path) -> None:
         )
 
 
-def test_read_database_parameterised(tmp_path: Path) -> None:
+def test_read_database_parameterised(tmp_path: Path, tmp_sqlite_db: Path) -> None:
     supports_adbc_sqlite = sys.version_info >= (3, 9) and sys.platform != "win32"
 
-    # setup underlying test data
-    tmp_path.mkdir(exist_ok=True)
-    create_temp_sqlite_db(test_db := str(tmp_path / "test.db"))
-    alchemy_engine = create_engine(f"sqlite:///{test_db}")
-
     # raw cursor "execute" only takes positional params, alchemy cursor takes kwargs
-    raw_conn: ConnectionOrCursor = sqlite3.connect(test_db)
+    alchemy_engine = create_engine(f"sqlite:///{tmp_sqlite_db}")
     alchemy_conn: ConnectionOrCursor = alchemy_engine.connect()
     alchemy_session: ConnectionOrCursor = sessionmaker(bind=alchemy_engine)()
+    raw_conn: ConnectionOrCursor = sqlite3.connect(tmp_sqlite_db)
 
     # establish parameterised queries and validate usage
     query = """