如何在unitest框架中模拟文本文件python2.7的创建？

import unittest
from unittest import mock

def create_text_file(filename):
    # 创建文本文件的逻辑
    pass

class TestCreateTextFile(unittest.TestCase):
    @mock.patch('builtins.open', create=True)
    def test_create_text_file(self, mock_open):
        # 模拟open函数返回的文件对象
        mock_file = mock_open.return_value

        # 调用被测试的函数
        create_text_file('test.txt')

        # 断言open函数被正确调用
        mock_open.assert_called_once_with('test.txt', 'w')

        # 断言文件对象的write方法被调用
        mock_file.write.assert_called_once_with('')

        # 断言文件对象的close方法被调用
        mock_file.close.assert_called_once()

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