Test method with a mock response, without create data - python

I'm testing with unittest a method, createData, which create something in my database.
def createData(self, content):
logging.info("Creating data...")
request = requests.post(self.url, data=content)
if request.status_code == 201:
logging.info("Data created")
else:
logging.error("Data not created")
return request
So I created two tests : one where I fail in creating data, with self.assertNotEqual(201, badRequest.status_code) and another where I succeed, with self.assertEqual(201, goodRequest.status_code). Of course, after, I delete this data.
I want to make this test without create any data. So I mock the response like that :
import unittest, logging
from data import Data as data
from unittest.mock import Mock
class TestData(unittest.TestCase):
def testCreateDataSuccess(self):
mock_response = Mock()
mock_response.status_code = 201
with self.assertLogs() as captured:
data.createData(data, goodContent).return_value = mock_response
self.assertEqual(201, mock_response.status_code)
self.assertEqual(captured.records[1].levelname, 'INFO')
However, despite mock, a data is created in my database. Could you tell me what I didn't understand ?
Thank you for your help !

Well, I found how to resolve this problem : using patch decorator.
I guess it "defuses" requests post in data, substituting response with the configured mock
import unittest, logging
from data import Data as data
from unittest.mock import patch
class TestData(unittest.TestCase):
#patch('data.requests.post')
def testCreateDataSuccess(self, mock_post):
mock_post.return_value.status_code = 201
with self.assertLogs() as captured:
response = data.createData(data, goodContent)
self.assertEqual(201, response.status_code)
self.assertEqual(captured.records[1].levelname, 'INFO')

Mocks are typically applied using mock.patch. What you want to mock is the response from requests.post, not the response from createData. Figuring out where to mock can be pretty tricky. This guide can help (https://alexmarandon.com/articles/python_mock_gotchas/)
You will probably need to rework how you import your code-under-test in order to be able to mock in the correct place.
import unittest, logging
import data # We are importing the entire module. This will let us patch in the correct location
from unittest.mock import Mock
class TestData(unittest.TestCase):
def testCreateDataSuccess(self):
mock_response = Mock()
mock_response.status_code = 201
# using mock.patch, we can replace the response from requests.post with our mock value. `requests` is imported in the `data` module so we mock `data.requests`
with mock.patch(data.requests.post, return_value=mock_response):
with self.assertLogs() as captured:
data.Data.createData(data, goodContent)
# self.assertEqual(201, mock_response.status_code) This line does not actually do anything - it's just testing that our mock has the status code we set. But we already know that, because we set it just a few lines ago.
self.assertEqual(captured.records[1].levelname, 'INFO')

Related

Mocking in Behave and Flask

I am trying to mock an HTTP request call using mock because I don't want to Behave to call it actually.
So I have this code scenario in matches.py file:
import request
def get_match():
response = request.get("https://example.com")
return response
And in my step definition match_steps.py for behave I have this:
def logoport_matches_response(context):
mock_response = context.text # this is the payload will come from feature file
with patch ('match') as mock_match:
mock_match.get_match.return_value = {"status": "success"}
But it seems this is not working because it still requesting an actual HTTP request.
I need to mock the get_match method to return {"status": "success"} result
Alright, I figure it out, you need to put your initialization inside the mock so:
from mock import patch
from matches import get_match
with patch ('match') as mock_match:
mock_match.return_value = {"status": "success"}
get_match()

In Django how to mock an object method called by views.py during its import?

I am writing System Tests for my Django app, where I test the complete application via HTTP requests and mock its external dependencies' APIs.
In views.py I have something like:
from external_service import ExternalService
externalService = ExternalService
data = externalService.get_data()
#crsf_exempt
def endpoint(request):
do_something()
What I want is to mock (or stub) ExternalService to return a predefined response when its method get_data() is called.
The problem is that when I run python manage.py test, views.py is loaded before my test class. So when I patch the object with a mocked one, the function get_data() was already called.
This solution didn't work either.
First off, don't call your method at import time. That can't be necessary, surely?
If get_data does something like a get request, e.g.
def get_data():
response = requests.get(DATA_URL)
if response.ok:
return response
else:
return None
Then you can mock it;
from unittest.mock import Mock, patch
from nose.tools import assert_is_none, assert_list_equal
from external_service import ExternalService
#patch('external_service.requests.get')
def test_getting_data(mock_get):
data = [{
'content': 'Response data'
}]
mock_get.return_value = Mock(ok=True)
mock_get.return_value.json.return_value = data
response = ExternalService.get_data()
assert_list_equal(response.json(), data)
#patch('external_service.requests.get')
def test_getting_data_error(mock_get):
mock_get.return_value.ok = False
response = ExternalService.get_data()
assert_is_none(response)
For this you'll need pip install nose if you don't already have it.

mocking session in requests library

In my python code I have global requests.session instance:
import requests
session = requests.session()
How can I mock it with Mock? Is there any decorator for this kind of operations? I tried following:
session.get = mock.Mock(side_effect=self.side_effects)
but (as expected) this code doesn't return session.get to original state after each test, like #mock.patch decorator do.
Since requests.session() returns an instance of the Session class, it is also possible to use patch.object()
from requests import Session
from unittest.mock import patch
#patch.object(Session, 'get')
def test_foo(mock_get):
mock_get.return_value = 'bar'
Use mock.patch to patch session in your module. Here you go, a complete working example https://gist.github.com/k-bx/5861641
With some inspiration from the previous answer and :
mock-attributes-in-python-mock
I was able to mock a session defined like this:
class MyClient(object):
"""
"""
def __init__(self):
self.session = requests.session()
with that: (the call to get returns a response with a status_code attribute set to 200)
def test_login_session():
with mock.patch('path.to.requests.session') as patched_session:
# instantiate service: Arrange
test_client = MyClient()
type(patched_session().get.return_value).status_code = mock.PropertyMock(return_value=200)
# Act (+assert)
resp = test_client.login_cookie()
# Assert
assert resp is None
I discovered the requests_mock library. It saved me a lot of bother. With pytest...
def test_success(self, requests_mock):
"""They give us a token.
"""
requests_mock.get("https://example.com/api/v1/login",
text=(
'{"result":1001, "errMsg":null,'
f'"token":"TEST_TOKEN",' '"expire":1799}'))
auth_token = the_module_I_am_testing.BearerAuth('test_apikey')
assert auth_token == 'TEST_TOKEN'
The module I am testing has my BearerAuth class which hits an endpoint for a token to start a requests.session with.

Python mock, django and requests

So, I've just started using mock with a Django project. I'm trying to mock out part of a view which makes a request to a remote API to confirm a subscription request was genuine (a form of verification as per the spec I'm working to).
What I have resembles:
class SubscriptionView(View):
def post(self, request, **kwargs):
remote_url = request.POST.get('remote_url')
if remote_url:
response = requests.get(remote_url, params={'verify': 'hello'})
if response.status_code != 200:
return HttpResponse('Verification of request failed')
What I now want to do is to use mock to mock out the requests.get call to change the response, but I can't work out how to do this for the patch decorator. I'd thought you do something like:
#patch(requests.get)
def test_response_verify(self):
# make a call to the view using self.app.post (WebTest),
# requests.get makes a suitable fake response from the mock object
How do I achieve this?
You're almost there. You're just calling it slightly incorrectly.
from mock import call, patch
#patch('my_app.views.requests')
def test_response_verify(self, mock_requests):
# We setup the mock, this may look like magic but it works, return_value is
# a special attribute on a mock, it is what is returned when it is called
# So this is saying we want the return value of requests.get to have an
# status code attribute of 200
mock_requests.get.return_value.status_code = 200
# Here we make the call to the view
response = SubscriptionView().post(request, {'remote_url': 'some_url'})
self.assertEqual(
mock_requests.get.call_args_list,
[call('some_url', params={'verify': 'hello'})]
)
You can also test that the response is the correct type and has the right content.
It's all in the documentation:
patch(target, new=DEFAULT, spec=None, create=False, spec_set=None, autospec=None, new_callable=None, **kwargs)
target should be a string in the form ‘package.module.ClassName’.
from mock import patch
# or #patch('requests.get')
#patch.object(requests, 'get')
def test_response_verify(self):
# make a call to the view using self.app.post (WebTest),
# requests.get makes a suitable fake response from the mock object

Unit-testing responses using the Requests library [duplicate]

I am writing an application that performs REST operations using Kenneth Reitz's requests library and I'm struggling to find a nice way to unit test these applications, because requests provides its methods via module-level methods.
What I want is the ability to synthesize the conversation between the two sides; provide a series of request assertions and responses.
It is in fact a little strange that the library has a blank page about end-user unit testing, while targeting user-friendliness and ease of use. There's however an easy-to-use library by Dropbox, unsurprisingly called responses. Here is its intro post. It says they've failed to employ httpretty, while stating no reason of the fail, and written a library with similar API.
import unittest
import requests
import responses
class TestCase(unittest.TestCase):
#responses.activate
def testExample(self):
responses.add(**{
'method' : responses.GET,
'url' : 'http://example.com/api/123',
'body' : '{"error": "reason"}',
'status' : 404,
'content_type' : 'application/json',
'adding_headers' : {'X-Foo': 'Bar'}
})
response = requests.get('http://example.com/api/123')
self.assertEqual({'error': 'reason'}, response.json())
self.assertEqual(404, response.status_code)
If you use specifically requests try httmock. It's wonderfully simple and elegant:
from httmock import urlmatch, HTTMock
import requests
# define matcher:
#urlmatch(netloc=r'(.*\.)?google\.com$')
def google_mock(url, request):
return 'Feeling lucky, punk?'
# open context to patch
with HTTMock(google_mock):
# call requests
r = requests.get('http://google.com/')
print r.content # 'Feeling lucky, punk?'
If you want something more generic (e.g. to mock any library making http calls) go for httpretty.
Almost as elegant:
import requests
import httpretty
#httpretty.activate
def test_one():
# define your patch:
httpretty.register_uri(httpretty.GET, "http://yipit.com/",
body="Find the best daily deals")
# use!
response = requests.get('http://yipit.com')
assert response.text == "Find the best daily deals"
HTTPretty is far more feature-rich - it offers also mocking status code, streaming responses, rotating responses, dynamic responses (with a callback).
You could use a mocking library such as Mocker to intercept the calls to the requests library and return specified results.
As a very simple example, consider this class which uses the requests library:
class MyReq(object):
def doSomething(self):
r = requests.get('https://api.github.com', auth=('user', 'pass'))
return r.headers['content-type']
Here's a unit test that intercepts the call to requests.get and returns a specified result for testing:
import unittest
import requests
import myreq
from mocker import Mocker, MockerTestCase
class MyReqTests(MockerTestCase):
def testSomething(self):
# Create a mock result for the requests.get call
result = self.mocker.mock()
result.headers
self.mocker.result({'content-type': 'mytest/pass'})
# Use mocker to intercept the call to requests.get
myget = self.mocker.replace("requests.get")
myget('https://api.github.com', auth=('user', 'pass'))
self.mocker.result(result)
self.mocker.replay()
# Now execute my code
r = myreq.MyReq()
v = r.doSomething()
# and verify the results
self.assertEqual(v, 'mytest/pass')
self.mocker.verify()
if __name__ == '__main__':
unittest.main()
When I run this unit test I get the following result:
.
----------------------------------------------------------------------
Ran 1 test in 0.004s
OK
Missing from these answers is requests-mock.
From their page:
>>> import requests
>>> import requests_mock
As a context manager:
>>> with requests_mock.mock() as m:
... m.get('http://test.com', text='data')
... requests.get('http://test.com').text
...
'data'
Or as a decorator:
>>> #requests_mock.mock()
... def test_func(m):
... m.get('http://test.com', text='data')
... return requests.get('http://test.com').text
...
>>> test_func()
'data'
using mocker like in srgerg's answer:
def replacer(method, endpoint, json_string):
from mocker import Mocker, ANY, CONTAINS
mocker = Mocker()
result = mocker.mock()
result.json()
mocker.count(1, None)
mocker.result(json_string)
replacement = mocker.replace("requests." + method)
replacement(CONTAINS(endpoint), params=ANY)
self.mocker.result(result)
self.mocker.replay()
For the requests library, this would intercept the request by method and endpoint you're hitting and replace the .json() on the response with the json_string passed in.
If you break out your response handler/parser into a separate function, you can work with requests.Response objects directly, without needing to mock the client-server interaction.
Code under test
from xml.dom import minidom
from requests.models import Response
def function_under_test(s3_response: Response):
doc = minidom.parseString(s3_response.text)
return (
s3_response.status_code,
doc.getElementsByTagName('Code').item(0).firstChild.data,
)
Test code
import unittest
from io import BytesIO
class Test(unittest.TestCase):
def test_it(self):
s3_response = Response()
s3_response.status_code = 404
s3_response.raw = BytesIO(b"""<?xml version="1.0" encoding="UTF-8"?>
<Error>
<Code>NoSuchKey</Code>
<Message>The resource you requested does not exist</Message>
<Resource>/mybucket/myfoto.jpg</Resource>
<RequestId>4442587FB7D0A2F9</RequestId>
</Error>
""")
parsed_response = function_under_test(s3_response)
self.assertEqual(404, parsed_response[0])
self.assertEqual("NoSuchKey", parsed_response[1])
There's a library for this, if you want to write your test server with Flask: requests-flask-adaptor
You just have to be careful with the order of imports when monkeypatching.

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