如何使用requests_mock来确保调用正确的会话?

时间:2017-07-18 18:46:43

标签: python python-3.x unit-testing python-requests

我的情况与此类似:

import unittest
import requests_mock
import requests

import mock

class ClassUnderTest:
    def __init__(self):
        self.session = requests.Session()
        self.foo_url = 'http://google.com'

    def do_foo(self):
        return self.session.get(self.foo_url)

    def do_foo_failing(self):
        # I want to prevent accidentally doing this sort of operation
        # instead of reusuing self.session
        return requests.get(self.foo_url)

我想确保方法正确执行,但也确保我使用self.session对象。在实践中,我遇到了这个问题,因为我错误地添加了requests.get来电而不是重新使用相同的会话。

然而,这意味着这样的测试实际上并未测试此功能:

class TestClassUnderTest(unittest.TestCase):

    @requests_mock.mock()
    def test_do_foo_should_pass(self, m):
        c = ClassUnderTest()

        m.get('http://google.com', status_code=200)
        r = c.do_foo()

        self.assertEqual(200, r.status_code)
        self.assertEqual(m.call_count, 1)

    @requests_mock.mock()
    def test_do_foo_should_fail(self, m):
        c = ClassUnderTest()
        m.get('http://google.com', status_code=200)
        r = c.do_foo_failing()

        self.assertEqual(200, r.status_code)
        self.assertEqual(m.call_count, 1)

我已经考虑用模拟替换self.session,但是我还必须在模拟上设置status_code之类的东西(在我的实际代码示例中我还需要做一些事情,比如添加模拟{{} 3}}以便消耗响应的代码正确运行)。

有没有办法使用requests_mock有效保证只使用self.session(在本例中不是requests.get)?

1 个答案:

答案 0 :(得分:1)

以下工作方法是将所有request.Session函数包装到MockClass中,并使用包装器跟踪它们的使用情况:

class MockSession:
    def __init__(self):
        self.session = requests.Session()
        self._called_methods = {}

        def session_decorator(f):
            def func(*args, **kwargs):
                if f.__name__ not in self._called_methods:
                    self._called_methods[f.__name__] = 1
                else:
                    self._called_methods[f.__name__] += 1
                return f(*args, **kwargs)
            return func

        for name, f in inspect.getmembers(self.session):
            if inspect.ismethod(f):
            setattr(self, name, session_decorator(f))

使用此模拟后,您可以访问._called_methods值以检查调用各个方法的频率。请注意,由于requests_mock的工作方式,您必须在运行时执行此操作(而不是通过简单地扩展具有类似功能的requests.Session类来加载时间。)

修改测试代码会导致:

class TestClassUnderTest(unittest.TestCase):

    @requests_mock.mock()
    def test_do_foo_should_pass(self, m):
        c = ClassUnderTest()
        c.session = MockSession()
        m.get('http://google.com', status_code=200)
        r = c.do_foo()

        self.assertEqual(200, r.status_code)
        self.assertEqual(m.call_count, 1)
        self.assertEqual(c.session._called_count['GET'], 1)

    @requests_mock.mock()
    def test_do_foo_should_fail(self, m):
        c = ClassUnderTest()
        c.session = MockSession()
        m.get('http://google.com', status_code=200)
        r = c.do_foo_failing()

        self.assertEqual(200, r.status_code)
        self.assertEqual(m.call_count, 1) 

        # This will fail with an attribute error 
        # because that function was never invoked on the mock session
        self.assertEqual(c.session._called_count['GET'], 1)