How to fix "TypeError: argument of type 'ConnectionHandler' is not iterable" when running a django test?

Question

When I do ```python -m unittest`` inside of my users app, I get this error:

TypeError: argument of type 'ConnectionHandler' is not iterable

I was customizing my User model in django and I wanted to make a test for it. I already did the migrations and the custom User model works good (I did with a new database), so I expected to run the test successfully. Here is my test code:

from django.test import TestCase
from django.contrib.auth import get_user_model

# Create your tests here.
class UsersManagersTests(TestCase):

    def test_create_user(self):
        User = get_user_model()
        user = User.objects.create_user(email='[email protected]', password='foo')
        self.assertEqual(user.email, '[email protected]')
        self.assertTrue(user.is_active)
        self.assertFalse(user.is_staff)
        self.assertFalse(user.is_superuser)
        try:
            # username is None for the AbstractUser option
            # username does not exist for the AbstractBaseUser option
            self.assertIsNone(user.username)
        except AttributeError:
            pass
        with self.assertRaises(TypeError):
            User.objects.create_user()
        with self.assertRaises(TypeError):
            User.objects.create_user(email='')
        with self.assertRaises(ValueError):
            User.objects.create_user(email='', password="foo")

    def test_create_superuser(self):
        User = get_user_model()
        admin_user = User.objects.create_superuser('[email protected]', 'foo')
        self.assertEqual(admin_user.email, '[email protected]')
        self.assertTrue(admin_user.is_active)
        self.assertTrue(admin_user.is_staff)
        self.assertTrue(admin_user.is_superuser)
        try:
            # username is None for the AbstractUser option
            # username does not exist for the AbstractBaseUser option
            self.assertIsNone(admin_user.username)
        except AttributeError:
            pass
        with self.assertRaises(ValueError):
            User.objects.create_superuser(
                email='[email protected]', password='foo', is_superuser=False)

settings.py

AUTH_USER_MODEL = 'users.CustomUser'

models.py

from django.db import models
from django.contrib.auth.models import AbstractBaseUser
from django.contrib.auth.models import PermissionsMixin
from django.utils.translation import gettext_lazy as _
from django.utils import timezone

from .managers import CustomUserManager

# Create your models here.
class CustomUser(AbstractBaseUser, PermissionsMixin):
    email = models.EmailField(_('email address'), unique=True)
    is_staff = models.BooleanField(default=False)
    is_active = models.BooleanField(default=True)
    is_deleted = models.BooleanField(default=False)
    date_joined = models.DateTimeField(default=timezone.now)
    updated_date=models.DateTimeField(auto_now=True)
    GENDER_CHOICES = (
        ('M', 'Male'),
        ('F', 'Female'),
        ('O', 'Others'),
    )
    gender = models.CharField(max_length=1, choices=GENDER_CHOICES)

    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = []

    objects = CustomUserManager()

    def __str__(self):
        return self.email

managers.py

from django.contrib.auth.base_user import BaseUserManager
from django.utils.translation import ugettext_lazy as _


class CustomUserManager(BaseUserManager):
    """
    Custom user model manager where email is the unique identifiers
    for authentication instead of usernames.
    """
    def create_user(self, email, password, **extra_fields):
        """
        Create and save a User with the given email and password.
        """
        if not email:
            raise ValueError(_('The Email must be set'))
        email = self.normalize_email(email)
        user = self.model(email=email, **extra_fields)
        user.set_password(password)
        user.save()
        return user

    def create_superuser(self, email, password, **extra_fields):
        """
        Create and save a SuperUser with the given email and password.
        """
        extra_fields.setdefault('is_staff', True)
        extra_fields.setdefault('is_superuser', True)
        extra_fields.setdefault('is_active', True)

        if extra_fields.get('is_staff') is not True:
            raise ValueError(_('Superuser must have is_staff=True.'))
        if extra_fields.get('is_superuser') is not True:
            raise ValueError(_('Superuser must have is_superuser=True.'))
        return self.create_user(email, password, **extra_fields)

Why does the test fail?

Answer 1

The error is probably due to the configuration of your IDE. What happens when you run "python manage.py test" ?