code: def test_read_data(self):
      mock = mock_open(read_data="foo")
      with patch("%s.open" % __name__, mock, create=True):
          h = open("bar")
          result = h.read()
  
      self.assertEqual(result, "foo")
  
imports: import unittest
  from warnings import catch_warnings
  from test.test_unittest.testmock.support import is_instance
  from unittest.mock import MagicMock, Mock, patch, sentinel, mock_open, call
label_desc: Use image node_id 5 for calling the TestMockOpen obj's underlying member method code with example usage: obj.test_read_data() without return types