Error testing django view

Hi everybody
I’m tryting to geht started with writing unittests in Django.
Here is my test:

from django.test import TestCase
from . models import Dataset

class DatasetTestCase(TestCase):

    def test_get_dataset(self):
        """Datsets can be loaded"""
        first_dataset = Dataset.objects.get(id=1)
        self.assertEqual(first_dataset.name, 'GeoCover')

The DJANGO_SETTINGS_MODULE=layermanager.settings is set.

When running the test im receiving the following error

django.core.exceptions.AppRegistryNotReady: Apps aren't loaded yet.

All apps are are loaded in “INSTALLED_APPS” in the settings.py

Can anybody help me solving this problem?

Thanks and best regards

Nils