code: def test_get_per_node_breakdown_as_dict_empty_summary(self):
      # Test with an empty lm_summary
      lm_summary_mock_data = {}
      self.lm_summary_mock.usage_by_node = lm_summary_mock_data
  
      result = get_per_node_breakdown_as_dict(self.lm_summary_mock)
  
      expected_output = {}
  
      self.assertEqual(result, expected_output)
  
file_path: ray/python/ray/tests/autoscaler/util.py
imports: import unittest
  from unittest.mock import Mock
  from ray.autoscaler._private.util import get_per_node_breakdown_as_dict
label_desc: Use image node_id 3 for calling the TestGetPerNodeBreakdown obj's underlying member method code with example usage: obj.test_get_per_node_breakdown_as_dict_empty_summary() without return types