mocking a method on django model using post_save signal - django

Question

So here's something I'm trying to figure out. I've got a method that is triggered by post_save
for this "Story" model. Works fine. What I need to do is figure out how to mock out the test, so I can fake the call and make assertions on my returns. I think I need to patch it somehow, but I've tried a couple different ways without much success. Best i can get is a object instance, but it ignores values I pass in.
I've commented in my test where my confusion lies. Any help would be welcome.
Here's my test:
from django.test import TestCase
from django.test.client import Client
from marketing.blog.models import Post, Tag
from unittest.mock import patch, Mock
class BlogTestCase(TestCase):
fixtures = [
'auth-test.json',
'blog-test.json',
]
def setUp(self):
self.client = Client()
def test_list(self):
# verify that we can load the list page
r = self.client.get('/blog/')
self.assertEqual(r.status_code, 200)
self.assertContains(r, "<h1>The Latest from Our Blog</h1>")
self.assertContains(r, 'Simple JavaScript Date Formatting')
self.assertContains(r, 'Page 1 of 2')
# loading a page out of range should redirect to last page
r = self.client.get('/blog/5/', follow=True)
self.assertEqual(r.redirect_chain, [
('http://testserver/blog/2/', 302)
])
self.assertContains(r, 'Page 2 of 2')
# verify that unpublished posts are not displayed
with patch('requests') as mock_requests:
# my futile attempt at mocking.
# creates <MagicMock> object but not able to call return_values
mock_requests.post.return_value = mock_response = Mock()
# this doesn't get to the magic mock object. Why?
mock_response.status_code = 201
p = Post.objects.get(id=5)
p.published = False
# post_save signal runs here and requests is called.
# Needs to be mocked.
p.save()
r = self.client.get('/blog/')
self.assertNotContains(r, 'Simple JavaScript Date Formatting')
Here's the model:
from django.db import models
from django.conf import settings
from django.db.models import signals
import requests
def update_console(sender, instance, raw, created, **kwargs):
# ignoring raw so that test fixture data can load without
# hitting this method.
if not raw:
update = instance
json_obj = {
'author': {
'alias': 'the_dude',
'token': 'the_dude'
},
'text': update.description,
}
headers = {'content-type': 'application/json'}
path = 'http://testserver.com:80/content/add/'
request = requests(path, 'POST',
json_obj, headers=headers,
)
if request.status_code < 299:
story_id = request.json().get('id')
if story_id:
# disconnect and reconnect signal so
# we don't enter recursion-land
signals.post_save.disconnect(
update_console,
sender = Story, )
update.story_id = story_id
update.save()
signals.post_save.connect(
update_console,
sender = Story, )
else:
raise AttributeError('Error Saving to console, '+ request.text)
class Story(models.Model):
"""Lets tell a story"""
story_id = models.CharField(
blank=True,
max_length=10,
help_text="This maps to the id of the post"
)
slug = models.SlugField(
unique=True,
help_text="This is used in URL and in code references.",
)
description = models.TextField(
help_text='2-3 short paragraphs about the story.',
)
def __str__(self):
return self.short_headline
# add/update this record as a custom update in console
signals.post_save.connect(update_console, sender = Story)

Answer 1

You need to patch requests in the module where it is actually used, i.e.
with patch('path.to.your.models.requests') as mock_requests:
mock_requests.return_value.status_code = 200
mock_requests.return_value.json.return_value = {'id': story_id'}
...
The documentation offers more detailed explanations on where to patch:
patch works by (temporarily) changing the object that a name points to with another one. There can be many names pointing to any individual object, so for patching to work you must ensure that you patch the name used by the system under test.
The basic principle is that you patch where an object is looked up, which is not necessarily the same place as where it is defined.
Here, you need to patch the name requests inside the models module, hence the need to provide its full path.