chore: import upstream snapshot with attribution

tests/database/test_session_context_coverage.py

@@ -0,0 +1,66 @@
+"""Coverage tests for database/session_context.py — basic import-level checks.
+
+Covered here:
+- DatabaseSessionError is a proper Exception subclass
+- with_user_database: decorator injects db_session
+- DatabaseAccessMixin.get_db_session: raises DeprecationWarning
+
+Additional branch coverage lives in test_session_context_deep_coverage.py.
+"""
+
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from local_deep_research.database.session_context import (
+    DatabaseAccessMixin,
+    DatabaseSessionError,
+    with_user_database,
+)
+
+MODULE = "local_deep_research.database.session_context"
+
+
+class TestGetUserDbSessionErrors:
+    """Tests for error paths in get_user_db_session."""
+
+    def test_database_session_error_is_exception(self):
+        """DatabaseSessionError is a proper Exception subclass."""
+        assert issubclass(DatabaseSessionError, Exception)
+        err = DatabaseSessionError("test message")
+        assert str(err) == "test message"
+
+
+class TestWithUserDatabase:
+    """Tests for with_user_database decorator."""
+
+    def test_injects_db_session(self):
+        """Decorator injects db_session as first argument."""
+
+        @with_user_database
+        def my_func(db_session, key):
+            return f"session={db_session}, key={key}"
+
+        mock_session = MagicMock()
+        with patch(f"{MODULE}.get_user_db_session") as mock_ctx:
+            mock_ctx.return_value.__enter__ = MagicMock(
+                return_value=mock_session
+            )
+            mock_ctx.return_value.__exit__ = MagicMock(return_value=False)
+            result = my_func("test_key")
+
+        assert "test_key" in result
+
+
+class TestDatabaseAccessMixin:
+    """Tests for DatabaseAccessMixin."""
+
+    def test_get_db_session_raises_deprecation(self):
+        """get_db_session raises DeprecationWarning."""
+
+        class MyService(DatabaseAccessMixin):
+            pass
+
+        svc = MyService()
+        with pytest.raises(DeprecationWarning):
+            svc.get_db_session()