code: def test_https_cert_and_key_file_not_found(self, mock_path):
      self.fp.write(
          "[TabPy]\n"
          "TABPY_TRANSFER_PROTOCOL = https\n"
          "TABPY_CERTIFICATE_FILE = foo\n"
          "TABPY_KEY_FILE = bar"
      )
      self.fp.close()
  
      mock_path.isfile.side_effect = lambda x: self.mock_isfile(
          x, {self.fp.name}
      )
  
      self.assertTabPyAppRaisesRuntimeError(
          "Error using HTTPS: The parameter(s) TABPY_CERTIFICATE_FILE and "
          "TABPY_KEY_FILE must point to an existing file."
      )
  
imports: import os
  import unittest
  from tempfile import NamedTemporaryFile
  import tabpy
  from tabpy.tabpy_server.app.util import validate_cert
  from tabpy.tabpy_server.app.app import TabPyApp
  from unittest.mock import patch
label_desc: Use image node_id 12 for calling the TestTransferProtocolValidation obj's underlying member method code with example usage: obj.test_https_cert_and_key_file_not_found(mock_path) without return types