Fix BlackSheep cross-task database access

BlackSheep initializes the ORM in its lifespan task, but request tasks could not see that context because the global fallback was disabled. Enable the same fallback used by the other ASGI integrations and add a regression test for the startup configuration.

Author: Sanjays2402

tests/contrib/test_blacksheep.py

@@ -0,0 +1,34 @@
+from unittest.mock import AsyncMock, patch
+
+import pytest
+from blacksheep.server import Application
+
+from tortoise.contrib.blacksheep import register_tortoise
+
+
+@pytest.mark.asyncio
+async def test_register_tortoise_enables_global_fallback() -> None:
+    with (
+        patch("tortoise.contrib.blacksheep.Tortoise") as mocked_tortoise,
+        patch("tortoise.contrib.blacksheep.get_connections"),
+    ):
+        mocked_tortoise.init = AsyncMock()
+        mocked_tortoise.close_connections = AsyncMock()
+        app = Application()
+        register_tortoise(
+            app,
+            db_url="sqlite://:memory:",
+            modules={"models": ["__main__"]},
+        )
+
+        await app.start()
+        mocked_tortoise.init.assert_awaited_once_with(
+            config=None,
+            config_file=None,
+            db_url="sqlite://:memory:",
+            modules={"models": ["__main__"]},
+            _enable_global_fallback=True,
+        )
+
+        await app.stop()
+        mocked_tortoise.close_connections.assert_awaited_once()

tortoise/contrib/blacksheep/__init__.py

@@ -89,7 +89,13 @@ def register_tortoise(
 
     @app.on_start
     async def init_orm(context) -> None:  # pylint: disable=W0612
-        await Tortoise.init(config=config, config_file=config_file, db_url=db_url, modules=modules)
+        await Tortoise.init(
+            config=config,
+            config_file=config_file,
+            db_url=db_url,
+            modules=modules,
+            _enable_global_fallback=True,
+        )
         logger.info("Tortoise-ORM started, %s, %s", get_connections()._get_storage(), Tortoise.apps)
         if generate_schemas:
             logger.info("Tortoise-ORM generating schema")