How can I mock requests and the response?

Question

I am trying to use Pythons mock package to mock Pythons requests module. What are the basic calls to get me working in below scenario?

In my views.py, I have a function that makes variety of requests.get() calls with different response each time

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

In my test class I want to do something like this but cannot figure out exact method calls

Step 1:

# 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'

Step 2:

Call my view

Step 3:

verify response contains 'a response', 'b response' , 'c response'

How can I complete Step 1 (mocking the requests module)?

Answer 1

This is how you can do it (you can run this file as-is):

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()

Important Note: If your MyGreatClass class lives in a different package, say my.great.package, you have to mock my.great.package.requests.get instead of just 'request.get'. In that case your test case would look like this:

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()

Enjoy!

Answer 2

Try using the responses library. Here is an example from their documentation:

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"}'

It provides quite a nice convenience over setting up all the mocking yourself.

There's also HTTPretty... it's not specific to requests library, more powerful in some ways though I found it doesn't lend itself so well to inspecting the requests that it intercepted, which responses does quite easily

There's also httmock.

A new library gaining popularity recently over the venerable requests is httpx, which adds first-class support for async. A mocking library for httpx is: https://github.com/lundberg/respx

Answer 3

Here is what worked for me:

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 4

I used requests-mock for writing tests for separate module:

# module.py
import requests

class A():

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

And the tests:

# 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()

Answer 5

this is how you mock requests.post, change it to your http method

@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 6

Here is a solution with requests Response class. It is cleaner IMHO.

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

def mocked_requests_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 7

I started out with Johannes Farhenkrug's answer here and it worked great for me. I needed to mock the requests library because my goal is to isolate my application and not test any 3rd party resources.

Then I read up some more about python's Mock library and I realized that I can replace the MockResponse class, which you might call a 'Test Double' or a 'Fake', with a python Mock class.

The advantage of doing so is access to things like assert_called_with, call_args and so on. No extra libraries are needed. Additional benefits such as 'readability' or 'its more pythonic' are subjective, so they may or may not play a role for you.

Here is my version, updated with using python's Mock instead of a test double:

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 links:

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

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

Answer 8

If you want to mock a fake response, another way to do it is to simply instantiate an instance of the base HttpResponse class, like so:

from django.http.response import HttpResponseBase

self.fake_response = HttpResponseBase()

Answer 9

This worked for me, although I haven't done much complicated testing yet.

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

Then you can create responses :

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

gives

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

Answer 10

One possible way to work around requests is using the library betamax, it records all requests and after that if you make a request in the same url with the same parameters the betamax will use the recorded request, I have been using it to test web crawler and it save me a lot time.

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

Can you use requests-mock instead?

Suppose your myview function instead takes a requests.Session object, makes requests with it, and does something to the output:

# 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

You can also use requests_mock with frameworks other than Pytest - the documentation is great.

Answer 12

Using requests_mock is easy to patch any requests

pip install requests-mock

from unittest import TestCase
import requests_mock
from <yourmodule> import <method> (auth)

class TestApi(TestCase):
  @requests_mock.Mocker()
  def test_01_authentication(self, m):
        """Successful authentication using username password"""
        token = 'token'
        m.post(f'http://localhost/auth', json= {'token': token})
        act_token =auth("user", "pass")
        self.assertEqual(act_token, token)

Answer 13

I will add this information since I had a hard time figuring how to mock an async api call.

Here is what I did to mock an async call.

Here is the function I wanted to test

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

You still need the MockResponse class

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

You add the MockResponseAsync class

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

    async def getResponse(self):
        return self.response

Here is the test. The important thing here is I create the response before since init function can't be async and the call to getResponse is async so it all checked out.

@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)

If you have a better way of doing that tell me but I think it's pretty clean like that.

Answer 14

The simplest way so far:

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 15

For those, who don't want to install additional libs for pytest, there is an example. I will duplicate it here with some extension, based on examples above:

import datetime

import requests


class MockResponse:
    def __init__(self, json_data, status_code):
        self.json_data = json_data
        self.status_code = status_code
        self.elapsed = datetime.timedelta(seconds=1)

    # mock json() method always returns a specific testing dictionary
    def json(self):
        return self.json_data


def test_get_json(monkeypatch):
    # Any arguments may be passed and mock_get() will always return our
    # mocked object, which only has the .json() method.
    def mock_get(*args, **kwargs):
        return MockResponse({'mock_key': 'mock_value'}, 418)

    # apply the monkeypatch for requests.get to mock_get
    monkeypatch.setattr(requests, 'get', mock_get)

    # app.get_json, which contains requests.get, uses the monkeypatch
    response = requests.get('https://fakeurl')
    response_json = response.json()

    assert response_json['mock_key'] == 'mock_value'
    assert response.status_code == 418
    assert response.elapsed.total_seconds() == 1


============================= test session starts ==============================
collecting ... collected 1 item

test_so.py::test_get_json PASSED                                          [100%]

============================== 1 passed in 0.07s ===============================

Answer 16

To avoid installing other dependencies you should create a fake response. This FakeResponse could be a child of Response (I think this is a good approach because it's more realistic) or just a simple class with the attributes you need.

Simple Fake class

class FakeResponse:
        status_code = None

        def __init__(self, *args, **kwargs):
            self.status_code = 500
            self.text = ""

Child of Response

class FakeResponse(Response):
        encoding = False
        _content = None

        def __init__(*args, **kwargs):
            super(FakeResponse).__thisclass__.status_code = 500
            # Requests requires to be not be None, if not throws an exception
            # For reference: https://github.com/psf/requests/issues/3698#issuecomment-261115119
            super(FakeResponse).__thisclass__.raw = io.BytesIO()

Answer 17

Just a helpful hint to those that are still struggling, converting from urllib or urllib2/urllib3 to requests AND trying to mock a response- I was getting a slightly confusing error when implementing my mock:

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

AttributeError: __enter__

Well, of course, if I knew anything about how with works (I didn't), I'd know it was a vestigial, unnecessary context (from PEP 343). Unnecessary when using the requests library because it does basically the same thing for you under the hood. Just remove the with and use bare requests.get(...) and Bob's your uncle.

Answer 18

For pytest users there is a convinient fixture from https://pypi.org/project/pytest-responsemock/

For example to mock GET to http://some.domain you can:

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 19

I will demonstrate how to detach your programming logic from the actual external library by swapping the real request with a fake one that returns the same data. In your view if external api call then this process is best

import pytest
from unittest.mock import patch
from django.test import RequestFactory

@patch("path(projectname.appname.filename).requests.post")
def test_mock_response(self, mock_get, rf: RequestFactory):
    mock_get.return_value.ok = Mock(ok=True)
    mock_get.return_value.status_code = 400
    mock_get.return_value.json.return_value = {you can define here dummy response}
    request = rf.post("test/", data=self.payload)
    response = view_name_view(request)

    expected_response = {
        "success": False,
        "status": "unsuccessful",
    }

    assert response.data == expected_response
    assert response.status_code == 400

Answer 20

If using pytest:

>>> import pytest
>>> import requests

>>> def test_url(requests_mock):
...     requests_mock.get('http://test.com', text='data')
...     assert 'data' == requests.get('http://test.com').text

Taken from the official documentation