fix: don't use default DB if pytest-xdist is not present (#51)

src/fastapi_toolsets/pytest/utils.py

@@ -117,46 +117,57 @@ async def create_db_session(
         await engine.dispose()
 
 
-def _get_xdist_worker() -> str | None:
-    """Return the pytest-xdist worker name, or ``None`` when not running under xdist.
+def _get_xdist_worker(default_test_db: str) -> str:
+    """Return the pytest-xdist worker name, or *default_test_db* when not running under xdist.
 
     Reads the ``PYTEST_XDIST_WORKER`` environment variable that xdist sets
     automatically in each worker process (e.g. ``"gw0"``, ``"gw1"``).
     When xdist is not installed or not active, the variable is absent and
-    ``None`` is returned.
+    *default_test_db* is returned instead.
+
+    Args:
+        default_test_db: Fallback value returned when ``PYTEST_XDIST_WORKER``
+            is not set.
     """
-    return os.environ.get("PYTEST_XDIST_WORKER")
+    return os.environ.get("PYTEST_XDIST_WORKER", default_test_db)
 
 
-def worker_database_url(database_url: str) -> str:
+def worker_database_url(database_url: str, default_test_db: str) -> str:
     """Derive a per-worker database URL for pytest-xdist parallel runs.
 
     Appends ``_{worker_name}`` to the database name so each xdist worker
-    operates on its own database.  When not running under xdist the
-    original URL is returned unchanged.
+    operates on its own database.  When not running under xdist,
+    ``_{default_test_db}`` is appended instead.
 
     The worker name is read from the ``PYTEST_XDIST_WORKER`` environment
     variable (set automatically by xdist in each worker process).
 
     Args:
         database_url: Original database connection URL.
+        default_test_db: Suffix appended to the database name when
+            ``PYTEST_XDIST_WORKER`` is not set.
 
     Returns:
-        A database URL with the worker-specific database name, or the
-        original URL when not running under xdist.
+        A database URL with a worker- or default-specific database name.
 
     Example:
         ```python
         # With PYTEST_XDIST_WORKER="gw0":
         url = worker_database_url(
-            "postgresql+asyncpg://user:pass@localhost/test_db"
+            "postgresql+asyncpg://user:pass@localhost/test_db",
+            default_test_db="test",
         )
         # "postgresql+asyncpg://user:pass@localhost/test_db_gw0"
+
+        # Without PYTEST_XDIST_WORKER:
+        url = worker_database_url(
+            "postgresql+asyncpg://user:pass@localhost/test_db",
+            default_test_db="test",
+        )
+        # "postgresql+asyncpg://user:pass@localhost/test_db_test"
         ```
     """
-    worker = _get_xdist_worker()
-    if worker is None:
-        return database_url
+    worker = _get_xdist_worker(default_test_db=default_test_db)
 
     url = make_url(database_url)
     url = url.set(database=f"{url.database}_{worker}")
@@ -166,6 +177,7 @@ def worker_database_url(database_url: str) -> str:
 @asynccontextmanager
 async def create_worker_database(
     database_url: str,
+    default_test_db: str = "test_db",
 ) -> AsyncGenerator[str, None]:
     """Create and drop a per-worker database for pytest-xdist isolation.
 
@@ -174,11 +186,13 @@ async def create_worker_database(
     creates a dedicated database for the worker, and yields the worker-specific
     URL.  On cleanup the worker database is dropped.
 
-    When not running under xdist (``PYTEST_XDIST_WORKER`` is unset), the
-    original URL is yielded without any database creation or teardown.
+    When running under xdist the database name is suffixed with the worker
+    name (e.g. ``_gw0``).  Otherwise it is suffixed with *default_test_db*.
 
     Args:
         database_url: Original database connection URL.
+        default_test_db: Suffix appended to the database name when
+            ``PYTEST_XDIST_WORKER`` is not set. Defaults to ``"test_db"``.
 
     Yields:
         The worker-specific database URL.
@@ -203,11 +217,9 @@ async def create_worker_database(
                 await cleanup_tables(session, Base)
         ```
     """
-    if _get_xdist_worker() is None:
-        yield database_url
-        return
-
-    worker_url = worker_database_url(database_url)
+    worker_url = worker_database_url(
+        database_url=database_url, default_test_db=default_test_db
+    )
     worker_db_name = make_url(worker_url).database
 
     engine = create_async_engine(

tests/test_pytest.py

@@ -299,40 +299,45 @@ class TestCreateDbSession:
 
 
 class TestGetXdistWorker:
-    """Tests for get_xdist_worker helper."""
+    """Tests for _get_xdist_worker helper."""
 
-    def test_returns_none_without_env_var(self, monkeypatch: pytest.MonkeyPatch):
-        """Returns None when PYTEST_XDIST_WORKER is not set."""
+    def test_returns_default_test_db_without_env_var(
+        self, monkeypatch: pytest.MonkeyPatch
+    ):
+        """Returns default_test_db when PYTEST_XDIST_WORKER is not set."""
         monkeypatch.delenv("PYTEST_XDIST_WORKER", raising=False)
-        assert _get_xdist_worker() is None
+        assert _get_xdist_worker("my_default") == "my_default"
 
     def test_returns_worker_name(self, monkeypatch: pytest.MonkeyPatch):
         """Returns the worker name from the environment variable."""
         monkeypatch.setenv("PYTEST_XDIST_WORKER", "gw0")
-        assert _get_xdist_worker() == "gw0"
+        assert _get_xdist_worker("ignored") == "gw0"
 
 
 class TestWorkerDatabaseUrl:
     """Tests for worker_database_url helper."""
 
-    def test_returns_original_url_without_xdist(self, monkeypatch: pytest.MonkeyPatch):
-        """URL is returned unchanged when not running under xdist."""
+    def test_appends_default_test_db_without_xdist(
+        self, monkeypatch: pytest.MonkeyPatch
+    ):
+        """default_test_db is appended when not running under xdist."""
         monkeypatch.delenv("PYTEST_XDIST_WORKER", raising=False)
         url = "postgresql+asyncpg://user:pass@localhost:5432/mydb"
-        assert worker_database_url(url) == url
+        result = worker_database_url(url, default_test_db="fallback")
+        assert make_url(result).database == "mydb_fallback"
 
     def test_appends_worker_id_to_database_name(self, monkeypatch: pytest.MonkeyPatch):
         """Worker name is appended to the database name."""
         monkeypatch.setenv("PYTEST_XDIST_WORKER", "gw0")
         url = "postgresql+asyncpg://user:pass@localhost:5432/db"
-        result = worker_database_url(url)
+        result = worker_database_url(url, default_test_db="unused")
         assert make_url(result).database == "db_gw0"
 
     def test_preserves_url_components(self, monkeypatch: pytest.MonkeyPatch):
         """Host, port, username, password, and driver are preserved."""
         monkeypatch.setenv("PYTEST_XDIST_WORKER", "gw2")
         url = "postgresql+asyncpg://myuser:secret@dbhost:6543/testdb"
-        result = make_url(worker_database_url(url))
+        result = make_url(worker_database_url(url, default_test_db="unused"))
 
         assert result.drivername == "postgresql+asyncpg"
         assert result.username == "myuser"
@@ -346,13 +351,40 @@ class TestCreateWorkerDatabase:
     """Tests for create_worker_database context manager."""
 
     @pytest.mark.anyio
-    async def test_yields_original_url_without_xdist(
+    async def test_creates_default_db_without_xdist(
         self, monkeypatch: pytest.MonkeyPatch
     ):
-        """Without xdist, yields the original URL without database operations."""
+        """Without xdist, creates a database suffixed with default_test_db."""
         monkeypatch.delenv("PYTEST_XDIST_WORKER", raising=False)
-        async with create_worker_database(DATABASE_URL) as url:
-            assert url == DATABASE_URL
+        default_test_db = "no_xdist_default"
+        expected_db = make_url(
+            worker_database_url(DATABASE_URL, default_test_db=default_test_db)
+        ).database
+
+        async with create_worker_database(
+            DATABASE_URL, default_test_db=default_test_db
+        ) as url:
+            assert make_url(url).database == expected_db
+
+            # Verify the database exists while inside the context
+            engine = create_async_engine(DATABASE_URL, isolation_level="AUTOCOMMIT")
+            async with engine.connect() as conn:
+                result = await conn.execute(
+                    text("SELECT 1 FROM pg_database WHERE datname = :name"),
+                    {"name": expected_db},
+                )
+                assert result.scalar() == 1
+            await engine.dispose()
+
+        # After context exit the database should be dropped
+        engine = create_async_engine(DATABASE_URL, isolation_level="AUTOCOMMIT")
+        async with engine.connect() as conn:
+            result = await conn.execute(
+                text("SELECT 1 FROM pg_database WHERE datname = :name"),
+                {"name": expected_db},
+            )
+            assert result.scalar() is None
+        await engine.dispose()
 
     @pytest.mark.anyio
     async def test_creates_and_drops_worker_database(
@@ -360,7 +392,9 @@ class TestCreateWorkerDatabase:
     ):
         """Worker database exists inside the context and is dropped after."""
         monkeypatch.setenv("PYTEST_XDIST_WORKER", "gw_test_create")
-        expected_db = make_url(worker_database_url(DATABASE_URL)).database
+        expected_db = make_url(
+            worker_database_url(DATABASE_URL, default_test_db="unused")
+        ).database
 
         async with create_worker_database(DATABASE_URL) as url:
             assert make_url(url).database == expected_db
@@ -389,7 +423,9 @@ class TestCreateWorkerDatabase:
     async def test_cleans_up_stale_database(self, monkeypatch: pytest.MonkeyPatch):
         """A pre-existing worker database is dropped and recreated."""
         monkeypatch.setenv("PYTEST_XDIST_WORKER", "gw_test_stale")
-        expected_db = make_url(worker_database_url(DATABASE_URL)).database
+        expected_db = make_url(
+            worker_database_url(DATABASE_URL, default_test_db="unused")
+        ).database
 
         # Pre-create the database to simulate a stale leftover
         engine = create_async_engine(DATABASE_URL, isolation_level="AUTOCOMMIT")