ensure Dict return from _filter_session_conf

Signed-off-by: varun-edachali-dbx <varun.edachali@databricks.com>

Author: varun-edachali-dbx

src/databricks/sql/backend/sea/backend.py

@@ -48,10 +48,10 @@
 
 
 def _filter_session_configuration(
-    session_configuration: Optional[Dict[str, Any]]
-) -> Optional[Dict[str, str]]:
+    session_configuration: Optional[Dict[str, Any]],
+) -> Dict[str, str]:
     if not session_configuration:
-        return None
+        return {}
 
     filtered_session_configuration = {}
     ignored_configs: Set[str] = set()

tests/unit/test_sea_backend.py

@@ -621,7 +621,7 @@ def test_utility_methods(self, sea_client):
         assert description[1][1] == "INT"  # type_code
         assert description[1][6] is False  # null_ok
 
-    def test_filter_session_configuration_string_values(self):
+    def test_filter_session_configuration(self):
         """Test that _filter_session_configuration converts all values to strings."""
         session_config = {
             "ANSI_MODE": True,
@@ -656,10 +656,7 @@ def test_filter_session_configuration_string_values(self):
         assert result == expected_result
 
         # Test with None input
-        assert _filter_session_configuration(None) is None
-
-        # Test with empty dict
-        assert _filter_session_configuration({}) is None
+        assert _filter_session_configuration(None) == {}
 
         # Test with only unsupported parameters
         unsupported_config = {