Mock patch method and an attribute

Question

I would like to patch an attribute of the data returned by a method.

Assuming I have the following simplified piece code:

@patch('requests.post')
class TestKeywordsApi(BaseTest):
    # Instantiate API class and set the apikey
    def setUp(self):
        BaseTest.setUp(self)
        self.fixtures = FIXTURES
        self.api = BaseApi()

    def mock_requests_post(self, url, data=None):
        ''' Mock method for post method from responses library.
            It replaces the responses.post calls in Api class.
        '''
        url = self.encode_url(url, data)
        if url:
            return self.fixtures[url]

    def test_save_success(self, mock_post):
        mock_post.side_effect = self.mock_requests_post

        response = self.api.post(keyword, params={...})

        # list of asserts

# original class calling requests.post    
import requests
class BaseApi(object):
    def post(self, action, params):
        ''' Sends a POST request to API '''
        response = requests.post(self.build_url(action), data=params).content

The code above fails because the mock method does not provide a mock/stub for 'content' attribute present in requests library. Does anyone know how to stub the content attribute?

Answer 1

your mocked post function needs to return an object that is more like requests 's response objects, one that has a .content attribute. eg:

from mock import Mock, patch
#[...]
def mock_requests_post(self, url, data=None):
    ''' Mock method for post method from responses library.
        It replaces the responses.post calls in Api class.
    '''
    mock_response = Mock()
    mock_response.content = 'my test response content'
    url = self.encode_url(url, data)
    if url:
        mock_response.url_called = self.fixtures[url]
    return mock_response

Answer 2

I found the following solution, which only modifies the mock_requests_post method, adding an internal class with the attribute that I need:

def mock_requests_post(self, url, data=None):
    ''' Mock method for post method from responses library.
        It replaces the responses.post calls in Api class.
    '''
    url = self.encode_url(url, data)

    class classWithAttributes(object):
        content = json.dumps(self.fixtures[url])

    if url:
        return classWithAttributes()