python - 为模拟的 asyncio.coroutine 设置返回值

Question

我试图在我正在测试的类中模拟一个辅助方法，但我无法设置返回值。相反，它是 None，这会导致进行调用的方法出错。

import unittest
import asyncio
import unittest.mock

class MyClass:

    @asyncio.coroutine
    def return_number(self):
        return 5

    @asyncio.coroutine
    def add_two(self):
        val = yield from self.return_number()
        return val + 2


class TestMyClass(unittest.TestCase):

    def setUp(self):
        self.mc = MyClass()

    def test_add(self):
        val = asyncio.get_event_loop().run_until_complete(self.mc.add_two())
        self.assertEqual(val, 7)

    def test_with_mock(self):
        """ Replace return_number with mocked method """
        mm = unittest.mock.MagicMock()
        mm.iter.return_value = 2
        self.mc.return_number = unittest.mock.Mock(return_value=mm)

        val = asyncio.get_event_loop().run_until_complete(self.mc.add_two())
        self.assertEqual(val, 4)


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

在这个例子中有什么方法可以模拟 return_number 以返回特定值吗？

Answer 1

你也可以做类似的事情:

def test_with_mock(self):
    """ Replace return_number with mocked method """
    with mock.patch.object(self.mc, "return_number", return_value=2):
        self.mc.return_number = asyncio.coroutine(self.mc.return_number)
        val = asyncio.get_event_loop().run_until_complete(self.mc.add_two())
        self.assertEqual(val, 4)