def test_optional_field(self):
testsubject = Subject(name = "testname", description = "testdescription", link = "http://www.google.ro/")
testsubject.save()
now = datetime.datetime.utcnow().replace(tzinfo=utc)
testassignment = Assignment(subject_id = testsubject, name="test", text = "asda", deadline = now)
testassignment.save()
testsubject.delete()
testassignment.delete()
