django.core.exceptions.ImproperlyConfigured：请求设置 AUTH_USER_MODEL，但未配置设置

Question

I am facing problem testing my User model Which is defined as AUTH_USER_MODEL = "accounts.User"

#settings.py
AUTH_USER_MODEL = "accounts.User"

and the accounts.models that is the code

import os

from django.contrib.auth.models import AbstractUser
from django.contrib.auth.models import UnicodeUsernameValidator
from django.core.validators import MinLengthValidator
from django.db import models
from django.utils.translation import gettext_lazy as _


class Avatar(models.Model):
    photo = models.ImageField(upload_to="avatars")

    def __str__(self):
        return os.path.basename(self.photo.name)


class User(AbstractUser):
    username = models.CharField(
        _("username"),
        max_length=150,
        unique=True,
        help_text=_(
            "Required. 150 characters or fewer. Letters, digits and @/./+/-/_ only."
        ),
        validators=[UnicodeUsernameValidator(), MinLengthValidator(3)],
        error_messages={"unique": _("A user with that username already exists."),},
    )
    avatar = models.ForeignKey(
        "Avatar", null=True, blank=True, on_delete=models.PROTECT
    )
    is_guest = models.BooleanField(default=False)

    class Meta:
        ordering = ["-id"]

When I am testing this in test_models.py using $ python -m pytest with following code in the file

from django.conf import settings


def test_custom_user_model():
    assert settings.AUTH_USER_MODEL == "accounts.User"

These are the errors on terminal

$ python -m pytest
========================================================================= test session starts ==========================================================================
platform win32 -- Python 3.9.1, pytest-6.2.3, py-1.10.0, pluggy-0.13.1
rootdir: C:\ProjectCode\Main-Project\Django-REST-Framework-React-BoilerPlate
plugins: cov-2.11.1, django-4.2.0
collected 1 item

accounts\tests\test_models.py F                                                                                                                                   [100%]

=============================================================================== FAILURES =============================================================================== 
________________________________________________________________________ test_custom_user_model ________________________________________________________________________ 

    def test_custom_user_model():
>       assert settings.AUTH_USER_MODEL == "accounts.User"

accounts\tests\test_models.py:5:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _  
venv\lib\site-packages\django\conf\__init__.py:82: in __getattr__
    self._setup(name)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _  

self = <LazySettings [Unevaluated]>, name = 'AUTH_USER_MODEL'

    def _setup(self, name=None):
        """
        Load the settings module pointed to by the environment variable. This
        is used the first time settings are needed, if the user hasn't
        configured settings manually.
        """
        settings_module = os.environ.get(ENVIRONMENT_VARIABLE)
        if not settings_module:
            desc = ("setting %s" % name) if name else "settings"
>           raise ImproperlyConfigured(
                "Requested %s, but settings are not configured. "
                "You must either define the environment variable %s "
                "or call settings.configure() before accessing settings."
                % (desc, ENVIRONMENT_VARIABLE))
E           django.core.exceptions.ImproperlyConfigured: Requested setting AUTH_USER_MODEL, but settings are not configured. You must either define the environment variable DJANGO_SETTINGS_MODULE or call settings.configure() before accessing settings.

venv\lib\site-packages\django\conf\__init__.py:63: ImproperlyConfigured
======================================================================= short test summary info ======================================================================== 
FAILED accounts/tests/test_models.py::test_custom_user_model - django.core.exceptions.ImproperlyConfigured: Requested setting AUTH_USER_MODEL, but settings are not co...
========================================================================== 1 failed in 0.61s =========================================================================== 

As I am not very good in testing but Now Question is that, I'm testing this in a wrong way or there is problem in settings config as django is suggesting, However the code is working fine in without any error but I need to pass the tests as well.

Answer 1

One generally uses manage.py to run things related to Django because it does various initial setup, specific to your problem it has a line like so (a little different according to the project name):

os.environ.setdefault('DJANGO_SETTINGS_MODULE', '<PROJECT_NAME_HERE>.settings')

You get the error because there is no environment variable DJANGO_SETTINGS_MODULE set when you try to run your test. Moving further one should be using the builtin test suite of Django to do testing in their Django projects as it provides much more convenience while testing. For more details see the documentation for Testing in Django

To use Django's test suite more efficiently you can change your file accounts\tests\test_models.py like so:

from django.test import TestCase
from django.conf import settings


class SettingsTestCase(TestCase):
    def test_custom_user_model(self):
        self.assertEqual(settings.AUTH_USER_MODEL, "accounts.User")

And then run them by running the following line in your terminal / cmd:

python manage.py test