Django - can't run tests while the application works normally - django

Question

Problem:
The problem is that I have an application which works ok, but when I try to run tests with the command:
coverage run manage.py test --settings=crm.settings.test
there occurs an error in the very beggining:
Creating test database for alias 'default'...
IntegrityError: profiles_usermodel.current_project_id may not be NULL
Previously I ran tests and everything worked nicely. Then I significantly changed the models and the application and tried to run tests -- as a result I got the mentioned above problem. What I did wrong?
My settings:
I have separate settings for tests:
My_application
|___My_application
|___urls.py
|___ __init__.py
|___wsgi.py
|___settings
|___base.py
|___test.py
|___local.py
|___profiles
|___models.py
|___views.py
|___tests
|___ __init__.py
|___models.py
The test settings are as follows:
"""Local test settings and globals which allows us to run our
test suite locally."""
from .base import *
########## TEST SETTINGS
TEST_RUNNER = 'discover_runner.DiscoverRunner'
TEST_DISCOVER_TOP_LEVEL = PROJECT_ROOT
TEST_DISCOVER_ROOT = PROJECT_ROOT
TEST_DISCOVER_PATTERN = "*"
########## IN-MEMORY TEST DATABASE
DATABASES = {
"default": {
"ENGINE": "django.db.backends.sqlite3",
"NAME": ":memory:",
"USER": "",
"PASSWORD": "",
"HOST": "",
"PORT": "",
},
}
INSTALLED_APPS += ('coverage',)
And there is the models from My_application/profiles/models.py (ommited several fields and methods):
from django.db import models
from django.contrib.auth.models import (
BaseUserManager, AbstractBaseUser, PermissionsMixin )
from django.contrib.auth.models import Group
class Project(models.Model):
name = models.CharField(max_length=255)
class UserModel(AbstractBaseUser, PermissionsMixin):
email = models.EmailField(max_length=255, unique=True, db_index=True,)
current_project = models.ForeignKey(Group, related_name='usermodel_current')
USERNAME_FIELD = 'email'
Also I use South for db migrations and django 1.5c2.

Answer 1

The error is being pretty explicit.
The test runner is attempting to create the database, and insert a record into 'profiles_usermodel'. This insertion is failing because the field 'current_project' cannot be null, but the creation process isn't setting anything into that field.
We'd have to see your tests to narrow down exactly where this is occurring.
If you don't care about getting it working "right" and just want it to work, update your user model, and add null=True to the kwargs of UserModel.current_project.