Cover legacy protobuf tests

Author: vchudnov-g

noxfile.py

@@ -255,7 +255,7 @@ def unit(session, install_grpc_gcp, install_grpc, install_async_rest):
 @nox.session(python=PYTHON_VERSIONS)
 def unit_protobuf_4x(session):
     """Run the unit test suite with protobuf 4.x."""
-    if session.python > "3.11":
+    if session.python in ["3.9", "3.10", "3.11"]:
         session.log("Skipping session: protobuf 4.x only runs on Python < 3.12")
         session.skip()
     # Pin protobuf to a 4.x version to ensure coverage for the legacy code path.

tests/unit/operations_v1/test_operations_rest_client.py

@@ -354,9 +354,9 @@ def test_operations_client_client_options(
 
     # Check the case quota_project_id is provided
     options = client_options.ClientOptions(quota_project_id="octopus")
-    with mock.patch.object(transport_class, "__init__") as patched:  # pragma: NO COVER
+    with mock.patch.object(transport_class, "__init__") as patched:
         patched.return_value = None
-        client = client_class(client_options=options, transport=transport_name)
+        client = client_class(client_options=options, transport=transport_name)  # pragma: NO COVER
         patched.assert_called_once_with(
             credentials=None,
             credentials_file=None,
@@ -366,7 +366,7 @@ def test_operations_client_client_options(
             quota_project_id="octopus",
             client_info=transports.base.DEFAULT_CLIENT_INFO,
             always_use_jwt_access=True,
-        )
+        )  # pragma: NO COVER
 
     # Check the case credentials_file is provided
     with warn_deprecated_credentials_file():