fixed critical errors related to survey subclassing and renaming of deadline and opening properties, and surveys in sidebar are now marked as such and have a red color if untaken
"""
39. Empty model tests
These test that things behave sensibly for the rare corner-case of a model with
no fields.
"""
from django.db import models
class Empty(models.Model):
pass
__test__ = {'API_TESTS':"""
>>> m = Empty()
>>> m.id
>>> m.save()
>>> m2 = Empty()
>>> m2.save()
>>> len(Empty.objects.all())
2
>>> m.id is not None
True
>>> existing = Empty(m.id)
>>> existing.save()
"""}