Pytest use django_db with rest framework - django

Question

I am trying to get a simple test to work against the real django_db not the test database using the django rest framework.
Basic test setup:
import pytest
from django.urls import reverse
from rest_framework import status
from rest_framework.test import APIClient
#pytest.mark.django_db
def test_airport_list_real():
client = APIClient()
response = client.get(reverse('query_flight:airports-list'))
assert response.status_code == 200
assert len(response.json()) > 0
Running this test I get:
___________________________ test_airport_list_real ____________________________
#pytest.mark.django_db
def test_airport_list_real():
client = APIClient()
response = client.get(reverse('query_flight:airports-list'))
assert response.status_code == 200
> assert len(response.json()) > 0
E assert 0 > 0
E + where 0 = len([])
E + where [] = functools.partial(<bound method Client._parse_json of <rest_framework.test.APIClient object at 0x000001A0AB793908>>, <Response status_code=200, "application/json">)()
E + where functools.partial(<bound method Client._parse_json of <rest_framework.test.APIClient object at 0x000001A0AB793908>>, <Response status_code=200, "application/json">) = <Response status_code=200, "application/json">.json
query_flight\tests\query_flight\test_api.py:60: AssertionError
When just running in the shell using pipenv run python manage.py shell I get the expected results:
In [1]: from django.urls import reverse
In [2]: from rest_framework.test import APIClient
In [3]: client = APIClient()
In [4]: response = client.get(reverse('query_flight:airports-list'))
In [5]: len(response.json())
Out[5]: 100
Using the following packages:
pytest-django==3.2.1
pytest [required: >=2.9, installed: 3.5.1]
djangorestframework==3.8.2
django [required: >=1.8, installed: 2.0.5]
Is there anyway to get pytest to access the real database in this way?

Answer 1

The django_db marker is only responsible to provide a connection to the test database for the marked test. The django settings passed to pytest-django are solely responsible for the selection of database used in the test run.
You can override the database usage in pytest-django by defining the django_db_setup fixture. Create a conftest.py file in the project root if you don't have it yet and override the db configuration:
# conftest.py
import pytest
#pytest.fixture(scope='session')
def django_db_setup():
settings.DATABASES['default'] = {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': 'path/to/dbfile.sqlite3',
}
However, you shouldn't use the real database in tests. Make a dump of your current db to get a snapshot of test data (python manage.py dumpdata > testdata.json) and load it into an empty test database to populate it before the test run:
# conftest.py
import pytest
from django.core.management import call_command
#pytest.fixture(scope='session')
def django_db_setup(django_db_setup, django_db_blocker):
with django_db_blocker.unblock():
call_command('loaddata', 'testdata.json')
Now, you can't possibly corrupt your real db when running tests; any future changes in real db will not cause the tests to fail (for example, when some data was deleted) and you always have a deterministic state on each test run. If you need some additional test data, add it in JSON format to testdata.json and your tests are good to go.
Source: Examples in pytest-django docs.

Answer 2

You've got a couple options. Using Django's TestClient or DRF's APIClient will use the test database and local version of your app by default. To connect to your live API, you could use a library like Requests to perform HTTP requests, then use those responses in your tests:
import requests
#pytest.mark.django_db
def test_airport_list_real():
response = requests.get('https://yourliveapi.biz')
assert response.status_code == 200
assert len(response.json()) > 0
Just be extra careful to perform exclusively read-only tests on that live database.