Running Django tests ends with MigrationSchemaMissing exception

I'm writing because I have a big problem. Well, I have a project in Django where I am using django-tenants. Unfortunately, I can't run any tests as these end up with the following error when calling migrations: ‘django.db.migrations.exceptions.MigrationSchemaMissing: Unable to create the django_migrations table (no schema has been selected to create in LINE 1: CREATE TABLE ‘django_migrations’ (‘id’ bigint NOT NULL PRIMA...’

The problem is quite acute. I am fed up with regression errors and would like to write tests for the code. I will appreciate any suggestion. If you have any suggestions for improvements to the project, I'd love to read about that too.

Project details below. Best regards

Dependencies

    [tool.poetry.dependencies]
    python = "^3.13"
    django = "5.1.8"  # The newest version is not compatible with django-tenants yet
    django-tenants = "^3.7.0"
    dj-database-url = "^2.3.0"
    django-bootstrap5 = "^25.1"
    django-bootstrap-icons = "^0.9.0"
    uvicorn = "^0.34.0"
    uvicorn-worker = "^0.3.0"
    gunicorn = "^23.0.0"
    whitenoise = "^6.8.2"
    encrypt-decrypt-fields = "^1.3.6"
    django-bootstrap-modal-forms = "^3.0.5"
    django-model-utils = "^5.0.0"
    werkzeug = "^3.1.3"
    tzdata = "^2025.2"
    pytz = "^2025.2"
    psycopg = {extras = ["binary", "pool"], version = "^3.2.4"}
    django-colorfield = "^0.13.0"
    sentry-sdk = {extras = ["django"], version = "^2.25.1"}

Settings.py

    import os
    from pathlib import Path
    from uuid import uuid4
    
    # External Dependencies
    import dj_database_url
    from django.contrib.messages import constants as messages
    from django.utils.translation import gettext_lazy as _
    
    BASE_DIR = Path(__file__).resolve().parent.parent
    PROJECT_DIR = os.path.join(BASE_DIR, os.pardir)
    TENANT_APPS_DIR = BASE_DIR / "tenant"
    
    DEBUG = os.environ.get("DEBUG", "False").lower() in ["true", "1", "yes"]
    TEMPLATE_DEBUG = DEBUG
    SECRET_KEY = os.environ.get("SECRET_KEY", str(uuid4())) if DEBUG else os.environ["SECRET_KEY"]
    VERSION = os.environ.get("VERSION", "develop")
    SECURE_SSL_REDIRECT = os.environ.get("SECURE_SSL_REDIRECT", "False").lower() in ["true", "1", "yes"]
    
    try:
        ALLOWED_HOSTS = os.environ["ALLOWED_HOSTS"].split(";")
    except KeyError:
        if not DEBUG:
            raise
    
    ALLOWED_HOSTS = ["localhost", ".localhost"]
    
    DEFAULT_DOMAIN = os.environ.get("DEFAULT_DOMAIN", ALLOWED_HOSTS[0])
    
    DEFAULT_FILE_STORAGE = "django_tenants.files.storage.TenantFileSystemStorage"
    
    SHARED_APPS = [
        "django_tenants",
        "sfe.common.apps.CommonConfig",
        "django.contrib.auth",
        "django.contrib.contenttypes",
        "django.contrib.sessions",
        "django.contrib.messages",
        "django.contrib.staticfiles",
    ]
    
    TENANT_APPS = [
        "django.contrib.auth",
        "django.contrib.contenttypes",
        "django.contrib.sessions",
        "django.contrib.messages",
        "django.contrib.staticfiles",
        "django_bootstrap5",
        "django_bootstrap_icons",
        "bootstrap_modal_forms",
        "sfe.tenant.apps.TenantConfig",
        "sfe.tenant.email_controller.apps.EmailControllerConfig",
    ]
    
    INSTALLED_APPS = list(SHARED_APPS) + [app for app in TENANT_APPS if app not in SHARED_APPS]
    
    MIDDLEWARE = [
        "sfe.common.middleware.HealthCheckMiddleware",
        "django.middleware.security.SecurityMiddleware",
        "whitenoise.middleware.WhiteNoiseMiddleware",
        "django.contrib.sessions.middleware.SessionMiddleware",
        "django.middleware.locale.LocaleMiddleware",
        "django.middleware.common.CommonMiddleware",
        "django.middleware.csrf.CsrfViewMiddleware",
        "django.contrib.auth.middleware.AuthenticationMiddleware",
        "django.contrib.messages.middleware.MessageMiddleware",
        "django.middleware.clickjacking.XFrameOptionsMiddleware",
    ]
    
    if DEBUG:
        INTERNAL_IPS = ["localhost", ".localhost"]
    
    ROOT_URLCONF = "sfe.urls_tenant"
    PUBLIC_SCHEMA_URLCONF = "sfe.urls_public"
    
    TEMPLATES = [
        {
            "BACKEND": "django.template.backends.django.DjangoTemplates",
            "DIRS": [],
            "APP_DIRS": True,
            "OPTIONS": {
                "context_processors": [
                    "django.template.context_processors.debug",
                    "django.template.context_processors.request",
                    "django.contrib.auth.context_processors.auth",
                    "django.contrib.messages.context_processors.messages",
                    "sfe.common.context_processor.version",
                    "sfe.common.context_processor.default_domain",
                ],
            },
        },
    ]
    
    WSGI_APPLICATION = "sfe.wsgi.application"
    
    default_db = dj_database_url.config(engine="django_tenants.postgresql_backend")
    DATABASES = {
        "default": {
            "OPTIONS": {"pool": True},
            **default_db,
        }
    }
    DATABASE_ROUTERS = ("django_tenants.routers.TenantSyncRouter",)
    TEST_RUNNER = "django.test.runner.DiscoverRunner"
    
    AUTH_PASSWORD_VALIDATORS = [
        {"NAME": "django.contrib.auth.password_validation.UserAttributeSimilarityValidator"},
        {"NAME": "django.contrib.auth.password_validation.MinimumLengthValidator"},
        {"NAME": "django.contrib.auth.password_validation.CommonPasswordValidator"},
        {"NAME": "django.contrib.auth.password_validation.NumericPasswordValidator"},
    ]
    
    TENANT_MODEL = "common.SystemTenant"
    TENANT_DOMAIN_MODEL = "common.Domain"
    PUBLIC_SCHEMA_NAME = "public"
    
    LANGUAGE_CODE = "pl"
    LANGUAGES = [("pl", "Polski"), ("en", "English")]
    LOCALE_PATHS = (os.path.join(BASE_DIR, "locale"),)
    
    TIME_ZONE = "UTC"
    USE_TZ = True
    USE_I18N = True
    
    PROJECT_ROOT = os.path.dirname(os.path.abspath(__file__))
    STATIC_URL = "/static/"
    STATIC_ROOT = os.path.join(PROJECT_ROOT, "static")
    
    LOGIN_URL = _("/login/")
    LOGOUT_REDIRECT_URL = "/"
    LOGIN_REDIRECT_URL = "/"
    SESSION_COOKIE_AGE = 86400
    
    DEFAULT_AUTO_FIELD = "django.db.models.BigAutoField"
    STATICFILES_STORAGE = "whitenoise.storage.CompressedManifestStaticFilesStorage"
    
    IMAP_TIMEOUT = 60
    ADMINS = [("Damian Giebas", "damian.giebas@gmail.com")]
    MANAGERS = ADMINS
    
    FIRST_DAY_OF_WEEK = 1

Project structure:

Simple test setup:

# External Dependencies
from django.utils.timezone import now
from django_tenants.test.cases import TenantTestCase
from django_tenants.utils import schema_context

# Current App
from sfe.tenant.models.due_date import DueDate


class DueDateModelTests(TenantTestCase):
    def setUp(self):
        super().setUp()

    def test_create_due_date(self):
        with schema_context(self.tenant.schema_name):
            DueDate.objects.create(date=now().date(), name="TestDueDate")

        assert DueDate.objects.all().count() == 1

def test_create_due_date(self):
    with schema_context(self.tenant.schema_name):
        DueDate.objects.create(date=now().date(), name="TestDueDate")
        self.assertEqual(DueDate.objects.all().count(), 1)

    # External Dependencies
    from django.conf import settings
    from django.db import migrations
    
    default_tenant_data = {
        "domain_url": settings.DEFAULT_DOMAIN,
        "schema_name": "public",
        "name": "default",
        "paid_until": "2100-12-31",
        "on_trial": True,
    }
    demo_tenant_data = {
        "domain_url": f"demo.{settings.DEFAULT_DOMAIN}",
        "schema_name": "demo",
        "name": "Demo Sp. z o. o.",
        "paid_until": "2100-12-31",
        "on_trial": True,
    }
    
    
    def add_entry(apps, schema_editor):
        del schema_editor
        SystemTenant = apps.get_model("common", "SystemTenant")
        SystemTenant(**default_tenant_data).save()
        SystemTenant(**demo_tenant_data).save()
    
    
    def remove_entry(apps, schema_editor):
        del schema_editor
        SystemTenant = apps.get_model("common", "SystemTenant")
        SystemTenant.objects.filter(**default_tenant_data).delete()
        SystemTenant.objects.filter(**demo_tenant_data).delete()
    
    
    class Migration(migrations.Migration):
        dependencies = [("common", "0001_initial")]
        operations = [
            migrations.RunPython(add_entry, remove_entry),
        ]

    # External Dependencies
    from django.conf import settings
    from django.db import migrations
    
    default_tenant_data = {
        "domain_url": settings.DEFAULT_DOMAIN,
        "schema_name": "public",
        "name": "default",
        "paid_until": "2100-12-31",
        "on_trial": True,
    }
    demo_tenant_data = {
        "domain_url": f"demo.{settings.DEFAULT_DOMAIN}",
        "schema_name": "demo",
        "name": "Demo Sp. z o. o.",
        "paid_until": "2100-12-31",
        "on_trial": True,
    }
    
    
    def add_entry(apps, schema_editor):
        del schema_editor
        SystemTenant = apps.get_model("common", "SystemTenant")
        SystemTenant(**default_tenant_data).save()
        SystemTenant(**demo_tenant_data).save()
    
    
    def remove_entry(apps, schema_editor):
        del schema_editor
        SystemTenant = apps.get_model("common", "SystemTenant")
        SystemTenant.objects.filter(**default_tenant_data).delete()
        SystemTenant.objects.filter(**demo_tenant_data).delete()
    
    
    def create_demo_schema(apps, schema_editor):
        schema_editor.execute("CREATE SCHEMA IF NOT EXISTS demo;")
    
    
    def delete_demo_schema(apps, schema_editor):
        schema_editor.execute("DROP SCHEMA IF EXISTS demo CASCADE;")
    
    
    class Migration(migrations.Migration):
        dependencies = [("common", "0001_initial")]
        operations = [
            migrations.RunPython(add_entry, remove_entry),
            migrations.RunPython(create_demo_schema, delete_demo_schema),
        ]