code: def test_empty_cache(self, mock_exists: Any, mock_open: Any) -> None:
      expected_failing_test_files: Set[str] = set()
  
      found_tests = get_previous_failures()
  
      self.assertSetEqual(expected_failing_test_files, found_tests)
      mock_open.assert_called()
  
imports: import io
  import json
  import pathlib
  import sys
  import unittest
  from typing import Any, Dict, Set
  from unittest import mock
label_desc: Use image node_id 2 for calling the TestParsePrevTests obj's underlying member method code with example usage: obj.test_empty_cache(mock_exists, mock_open) without return types