mocking of builtins (python2/3)

mock_open.py

"""
This is the example of mocking the builtin `open` function in python 2/3.
"""
from __future__ import print_function
import sys
import unittest

if sys.version_info.major == 3:
    from unittest import mock
else:
    # Expect the `mock` package for python 2.
    # https://pypi.python.org/pypi/mock
    import mock


def use_of_open():
    """
    Example function, with usage of the builtin `open` function.

    :return: indented content's string of this file
    :rtype: string
    """
    with open(__file__) as f_:
        my_content = f_.read()
    return my_content


class TestMockOpen(unittest.TestCase):

    def test_mock_the_open(self):
        """
        Mocking the builtins open function adaptively for python 2/3
        :return: None
        """

        # Get a appropriate "builtin" module name for pythons 2/3.
        if sys.version_info.major == 3:
            builtin_module_name = 'builtins'
        else:
            builtin_module_name = '__builtin__'

        mock_data = """\
        spam 1
        eggs 2
        pig 3"""

        with mock.patch('{}.open'.format(builtin_module_name),
                        mock.mock_open(read_data=mock_data),
                        create=False
                        ):
            content = use_of_open()

        self.assertEqual(
            content,
            mock_data,
            'Mocked `open` should return `mock_data` test value!'
            )

if __name__ == '__main__':
    unittest.main()

I am working on such a project for now, and I think having including future library and explicitly importing open in the code can solve the issue