如何模拟请求和响应？

Question

我正在尝试使用 Pythons mock package 来模拟 Pythons requests 模块。让我在以下场景中工作的基本调用是什么？

在我的views.py 中，我有一个函数可以进行各种requests.get() 调用，每次都有不同的响应

def myview(request):
  res1 = requests.get('aurl')
  res2 = request.get('burl')
  res3 = request.get('curl')

在我的测试类中，我想做这样的事情，但无法弄清楚确切的方法调用

第 1 步：

# Mock the requests module
# when mockedRequests.get('aurl') is called then return 'a response'
# when mockedRequests.get('burl') is called then return 'b response'
# when mockedRequests.get('curl') is called then return 'c response'

第 2 步：

调用我的观点

第三步：

验证响应包含'a response'、'b response'、'c response'

如何完成第 1 步（模拟请求模块）？

Answer 1

你能改用requests-mock吗？

假设你的 myview 函数取而代之的是一个 requests.Session 对象，用它发出请求，并对输出做一些事情：

# mypackage.py
def myview(session):
    res1 = session.get("http://aurl")
    res2 = session.get("http://burl")
    res3 = session.get("http://curl")
    return f"{res1.text}, {res2.text}, {res3.text}"

# test_myview.py
from mypackage import myview
import requests

def test_myview(requests_mock):
    # set up requests
    a_req = requests_mock.get("http://aurl", text="a response")
    b_req = requests_mock.get("http://burl", text="b response")
    c_req = requests_mock.get("http://curl", text="c response")

    # test myview behaviour
    session = requests.Session()
    assert myview(session) == "a response, b response, c response"

    # check that requests weren't called repeatedly
    assert a_req.called_once
    assert b_req.called_once
    assert c_req.called_once
    assert requests_mock.call_count == 3

您还可以将requests_mock 与 Pytest 以外的框架一起使用 - 文档很棒。

Answer 2

目前为止最简单的方法：

from unittest import TestCase
from unittest.mock import Mock, patch

from .utils import method_foo


class TestFoo(TestCase):

    @patch.object(utils_requests, "post")  # change to desired method here
    def test_foo(self, mock_requests_post):
        # EXPLANATION: mocked 'post' method above will return some built-in mock, 
        # and its method 'json' will return mock 'mock_data',
        # which got argument 'return_value' with our data to be returned
        mock_data = Mock(return_value=[{"id": 1}, {"id": 2}])
        mock_requests_post.return_value.json = mock_data

        method_foo()

        # TODO: asserts here


"""
Example of method that you can test in utils.py
"""
def method_foo():
    response = requests.post("http://example.com")
    records = response.json()
    for record in records:
        print(record.get("id"))
        # do other stuff here

Answer 3

这是一个带有 requests Response 类的解决方案。恕我直言，它更干净。

import json
from unittest.mock import patch
from requests.models import Response

def mocked_request_get(*args, **kwargs):
    response_content = None
    request_url = kwargs.get('url', None)
    if request_url == 'aurl':
        response_content = json.dumps('a response')
    elif request_url == 'burl':
        response_content = json.dumps('b response')
    elif request_url == 'curl':
        response_content = json.dumps('c response')
    response = Response()
    response.status_code = 200
    response._content = str.encode(response_content)
    return response

@mock.patch('requests.get', side_effect=mocked_requests_get)
def test_fetch(self, mock_get):
     response = requests.get(url='aurl')
     assert ...

Answer 4

这对我有用，虽然我还没有做太多复杂的测试。

import json
from requests import Response

class MockResponse(Response):
    def __init__(self,
                 url='http://example.com',
                 headers={'Content-Type':'text/html; charset=UTF-8'},
                 status_code=200,
                 reason = 'Success',
                 _content = 'Some html goes here',
                 json_ = None,
                 encoding='UTF-8'
                 ):
    self.url = url
    self.headers = headers
    if json_ and headers['Content-Type'] == 'application/json':
        self._content = json.dumps(json_).encode(encoding)
    else:
        self._content = _content.encode(encoding)

    self.status_code = status_code
    self.reason = reason
    self.encoding = encoding

然后您可以创建响应：

mock_response = MockResponse(
    headers={'Content-Type' :'application/json'},
    status_code=401,
    json_={'success': False},
    reason='Unauthorized'
)
mock_response.raise_for_status()

给予

requests.exceptions.HTTPError: 401 Client Error: Unauthorized for url: http://example.com

Answer 5

对于 pytest 用户，https://pypi.org/project/pytest-responsemock/ 提供了一个方便的夹具

例如，将 GET 模拟为 http://some.domain，您可以：

def test_me(response_mock):

    with response_mock('GET http://some.domain -> 200 :Nice'):
        response = send_request()
        assert result.ok
        assert result.content == b'Nice'

Answer 6

我从Johannes Farhenkrug 的答案here 开始，它对我很有用。我需要模拟 requests 库，因为我的目标是隔离我的应用程序，而不是测试任何第三方资源。

然后我阅读了有关 python 的 Mock 库的更多信息，我意识到我可以用 python Mock 类替换 MockResponse 类，你可能称之为“Test Double”或“Fake”。

这样做的好处是可以访问assert_called_with、call_args 等内容。不需要额外的库。诸如“可读性”或“它更 Pythonic”之类的其他好处是主观的，因此它们可能对您起作用，也可能不会起作用。

这是我的版本，使用 python 的 Mock 而不是测试替身进行了更新：

import json
import requests
from unittest import mock

# defube stubs
AUTH_TOKEN = '{"prop": "value"}'
LIST_OF_WIDGETS = '{"widgets": ["widget1", "widget2"]}'
PURCHASED_WIDGETS = '{"widgets": ["purchased_widget"]}'


# exception class when an unknown URL is mocked
class MockNotSupported(Exception):
  pass


# factory method that cranks out the Mocks
def mock_requests_factory(response_stub: str, status_code: int = 200):
    return mock.Mock(**{
        'json.return_value': json.loads(response_stub),
        'text.return_value': response_stub,
        'status_code': status_code,
        'ok': status_code == 200
    })


# side effect mock function
def mock_requests_post(*args, **kwargs):
    if args[0].endswith('/api/v1/get_auth_token'):
        return mock_requests_factory(AUTH_TOKEN)
    elif args[0].endswith('/api/v1/get_widgets'):
        return mock_requests_factory(LIST_OF_WIDGETS)
    elif args[0].endswith('/api/v1/purchased_widgets'):
        return mock_requests_factory(PURCHASED_WIDGETS)
    
    raise MockNotSupported


# patch requests.post and run tests
with mock.patch('requests.post') as requests_post_mock:
  requests_post_mock.side_effect = mock_requests_post
  response = requests.post('https://myserver/api/v1/get_widgets')
  assert response.ok is True
  assert response.status_code == 200
  assert 'widgets' in response.json()
  
  # now I can also do this
  requests_post_mock.assert_called_with('https://myserver/api/v1/get_widgets')

Repl.it 链接：

https://repl.it/@abkonsta/Using-unittestMock-for-requestspost#main.py

https://repl.it/@abkonsta/Using-test-double-for-requestspost#main.py

Answer 7

尝试使用responses library。以下是来自their documentation 的示例：

import responses
import requests

@responses.activate
def test_simple():
    responses.add(responses.GET, 'http://twitter.com/api/1/foobar',
                  json={'error': 'not found'}, status=404)

    resp = requests.get('http://twitter.com/api/1/foobar')

    assert resp.json() == {"error": "not found"}

    assert len(responses.calls) == 1
    assert responses.calls[0].request.url == 'http://twitter.com/api/1/foobar'
    assert responses.calls[0].response.text == '{"error": "not found"}'

它为自己设置所有模拟提供了相当不错的便利。

还有HTTPretty:

它并不特定于 requests 库，虽然我发现它不适合检查它拦截的请求，但在某些方面更强大，responses 很容易做到这一点

还有httmock。

Answer 8

我将添加此信息，因为我很难弄清楚如何模拟异步 api 调用。

这是我模拟异步调用所做的。

这是我要测试的功能

async def get_user_info(headers, payload):
    return await httpx.AsyncClient().post(URI, json=payload, headers=headers)

你仍然需要 MockResponse 类

class MockResponse:
    def __init__(self, json_data, status_code):
        self.json_data = json_data
        self.status_code = status_code

    def json(self):
        return self.json_data

您添加 MockResponseAsync 类

class MockResponseAsync:
    def __init__(self, json_data, status_code):
        self.response = MockResponse(json_data, status_code)

    async def getResponse(self):
        return self.response

这是测试。这里重要的是我之前创建了响应，因为 init 函数不能是异步的，并且对 getResponse 的调用是异步的，所以它都被检查出来了。

@pytest.mark.asyncio
@patch('httpx.AsyncClient')
async def test_get_user_info_valid(self, mock_post):
    """test_get_user_info_valid"""
    # Given
    token_bd = "abc"
    username = "bob"
    payload = {
        'USERNAME': username,
        'DBNAME': 'TEST'
    }
    headers = {
        'Authorization': 'Bearer ' + token_bd,
        'Content-Type': 'application/json'
    }
    async_response = MockResponseAsync("", 200)
    mock_post.return_value.post.return_value = async_response.getResponse()

    # When
    await api_bd.get_user_info(headers, payload)

    # Then
    mock_post.return_value.post.assert_called_once_with(
        URI, json=payload, headers=headers)

如果你有更好的方法，请告诉我，但我认为这样很干净。

Answer 9

只是对那些仍在苦苦挣扎的人的有用提示，从 urllib 或 urllib2/urllib3 转换为请求并尝试模拟响应 - 我在实现模拟时遇到了一个稍微令人困惑的错误：

with requests.get(path, auth=HTTPBasicAuth('user', 'pass'), verify=False) as url:

属性错误：__enter__

当然，如果我知道with 的工作原理（我不知道），我会知道这是一个退化的、不必要的context（来自PEP 343）。使用 requests 库时是不必要的，因为它对您基本相同 under the hood。只需删除with 并使用裸requests.get(...) 和Bob's your uncle。

Answer 10

解决请求的一种可能方法是使用库 betamax，它记录所有请求，然后如果您使用相同参数在同一个 url 中发出请求，betamax 将使用记录的请求，我一直在使用它测试网络爬虫，它节省了我很多时间。

import os

import requests
from betamax import Betamax
from betamax_serializers import pretty_json


WORKERS_DIR = os.path.dirname(os.path.abspath(__file__))
CASSETTES_DIR = os.path.join(WORKERS_DIR, u'resources', u'cassettes')
MATCH_REQUESTS_ON = [u'method', u'uri', u'path', u'query']

Betamax.register_serializer(pretty_json.PrettyJSONSerializer)
with Betamax.configure() as config:
    config.cassette_library_dir = CASSETTES_DIR
    config.default_cassette_options[u'serialize_with'] = u'prettyjson'
    config.default_cassette_options[u'match_requests_on'] = MATCH_REQUESTS_ON
    config.default_cassette_options[u'preserve_exact_body_bytes'] = True


class WorkerCertidaoTRT2:
    session = requests.session()

    def make_request(self, input_json):
        with Betamax(self.session) as vcr:
            vcr.use_cassette(u'google')
            response = session.get('http://www.google.com')

https://betamax.readthedocs.io/en/latest/

Answer 11

您可以这样做（您可以按原样运行此文件）：

import requests
import unittest
from unittest import mock

# This is the class we want to test
class MyGreatClass:
    def fetch_json(self, url):
        response = requests.get(url)
        return response.json()

# This method will be used by the mock to replace requests.get
def mocked_requests_get(*args, **kwargs):
    class MockResponse:
        def __init__(self, json_data, status_code):
            self.json_data = json_data
            self.status_code = status_code

        def json(self):
            return self.json_data

    if args[0] == 'http://someurl.com/test.json':
        return MockResponse({"key1": "value1"}, 200)
    elif args[0] == 'http://someotherurl.com/anothertest.json':
        return MockResponse({"key2": "value2"}, 200)

    return MockResponse(None, 404)

# Our test case class
class MyGreatClassTestCase(unittest.TestCase):

    # We patch 'requests.get' with our own method. The mock object is passed in to our test case method.
    @mock.patch('requests.get', side_effect=mocked_requests_get)
    def test_fetch(self, mock_get):
        # Assert requests.get calls
        mgc = MyGreatClass()
        json_data = mgc.fetch_json('http://someurl.com/test.json')
        self.assertEqual(json_data, {"key1": "value1"})
        json_data = mgc.fetch_json('http://someotherurl.com/anothertest.json')
        self.assertEqual(json_data, {"key2": "value2"})
        json_data = mgc.fetch_json('http://nonexistenturl.com/cantfindme.json')
        self.assertIsNone(json_data)

        # We can even assert that our mocked method was called with the right parameters
        self.assertIn(mock.call('http://someurl.com/test.json'), mock_get.call_args_list)
        self.assertIn(mock.call('http://someotherurl.com/anothertest.json'), mock_get.call_args_list)

        self.assertEqual(len(mock_get.call_args_list), 3)

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

重要提示：如果您的 MyGreatClass 类位于不同的包中，例如 my.great.package，您必须模拟 my.great.package.requests.get 而不仅仅是“request.get”。在这种情况下，您的测试用例将如下所示：

import unittest
from unittest import mock
from my.great.package import MyGreatClass

# This method will be used by the mock to replace requests.get
def mocked_requests_get(*args, **kwargs):
    # Same as above


class MyGreatClassTestCase(unittest.TestCase):

    # Now we must patch 'my.great.package.requests.get'
    @mock.patch('my.great.package.requests.get', side_effect=mocked_requests_get)
    def test_fetch(self, mock_get):
        # Same as above

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

享受吧！

Answer 12

这就是你模拟 requests.post 的方式，将其更改为你的 http 方法

@patch.object(requests, 'post')
def your_test_method(self, mockpost):
    mockresponse = Mock()
    mockpost.return_value = mockresponse
    mockresponse.text = 'mock return'

    #call your target method now

Answer 13

这对我有用：

import mock
@mock.patch('requests.get', mock.Mock(side_effect = lambda k:{'aurl': 'a response', 'burl' : 'b response'}.get(k, 'unhandled request %s'%k)))

Answer 14

如果你想模拟一个假响应，另一种方法是简单地实例化一个基础 HttpResponse 类的实例，如下所示：

from django.http.response import HttpResponseBase

self.fake_response = HttpResponseBase()

Answer 15

我使用requests-mock 为单独的模块编写测试：

# module.py
import requests

class A():

    def get_response(self, url):
        response = requests.get(url)
        return response.text

还有测试：

# tests.py
import requests_mock
import unittest

from module import A


class TestAPI(unittest.TestCase):

    @requests_mock.mock()
    def test_get_response(self, m):
        a = A()
        m.get('http://aurl.com', text='a response')
        self.assertEqual(a.get_response('http://aurl.com'), 'a response')
        m.get('http://burl.com', text='b response')
        self.assertEqual(a.get_response('http://burl.com'), 'b response')
        m.get('http://curl.com', text='c response')
        self.assertEqual(a.get_response('http://curl.com'), 'c response')

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