test: share unbound unit test sessions (#39690)

api/tests/unit_tests/conftest.py

@@ -152,6 +152,18 @@ def _sqlite_session_factory(
     return factory
 
 
+@pytest.fixture
+def _unbound_session_factory(
+    _sqlite_session_factory: sessionmaker[Session],
+    monkeypatch: pytest.MonkeyPatch,
+) -> sessionmaker[Session]:
+    """Create one unbound factory and install it as the global test factory."""
+
+    factory = sessionmaker()
+    monkeypatch.setattr(session_factory_module, "_session_maker", factory)
+    return factory
+
+
 @pytest.fixture
 def sqlite_engine(_sqlite_engine: Engine) -> Engine:
     """Expose the pristine full-schema SQLite engine to tests."""
@@ -178,6 +190,25 @@ def sqlite_session(_sqlite_session_factory: sessionmaker[Session]) -> Iterator[S
         yield session
 
 
+@pytest.fixture
+def unbound_session_factory(_unbound_session_factory: sessionmaker[Session]) -> sessionmaker[Session]:
+    """Expose an unbound factory for paths that must not require persistence."""
+
+    return _unbound_session_factory
+
+
+@pytest.fixture
+def unbound_session(_unbound_session_factory: sessionmaker[Session]) -> Iterator[Session]:
+    """Yield an unbound Session for paths that must not require persistence.
+
+    Bind-requiring database access fails, while bind-free Session operations can
+    still succeed.
+    """
+
+    with _unbound_session_factory() as session:
+        yield session
+
+
 def persist_service_api_tenant_owner(session: Session, tenant: Tenant, owner: Account) -> TenantAccountJoin:
     """Persist the owner identity resolved by service-API app authentication.
 

api/tests/unit_tests/services/test_human_input_service.py

@@ -41,12 +41,6 @@ from services.human_input_service import (
 )
 
 
-@pytest.fixture
-def unbound_session_factory() -> sessionmaker[Session]:
-    """Supply the required constructor dependency without enabling database access."""
-    return sessionmaker()
-
-
 def _make_app(mode: AppMode) -> App:
     return App(
         id="app-id",

api/tests/unit_tests/test_sqlite_fixtures.py

@@ -5,6 +5,7 @@ from threading import Barrier
 import pytest
 from sqlalchemy import create_engine, inspect, text
 from sqlalchemy.engine import URL, Engine
+from sqlalchemy.exc import UnboundExecutionError
 from sqlalchemy.orm import Session, sessionmaker
 from sqlalchemy.pool import QueuePool
 
@@ -58,6 +59,25 @@ def test_core_session_factory_uses_the_shared_sqlite_session_factory(
         assert session.scalar(text("SELECT value FROM global_factory_probe")) == 42
 
 
+def test_unbound_session_factory_disables_explicit_and_global_database_access(
+    unbound_session_factory: sessionmaker[Session],
+) -> None:
+    assert session_factory_module.session_factory.get_session_maker() is unbound_session_factory
+
+    with unbound_session_factory() as session:
+        with pytest.raises(UnboundExecutionError):
+            session.get_bind()
+
+    with session_factory_module.session_factory.create_session() as session:
+        with pytest.raises(UnboundExecutionError):
+            session.execute(text("SELECT 1"))
+
+
+def test_unbound_session_rejects_database_access(unbound_session: Session) -> None:
+    with pytest.raises(UnboundExecutionError):
+        unbound_session.scalar(text("SELECT 1"))
+
+
 def test_sqlite_session_factory_shares_one_database_across_worker_sessions(
     sqlite_session_factory: sessionmaker[Session],
 ) -> None: