'Empty strings foreign key values don\'t get converted to None (#19299).'

@skipIfDBFeature('interprets_empty_strings_as_nulls')
def test_empty_string_fk(self):

    char_model_empty = PrimaryKeyCharModel.objects.create(string='')
    fk_model_empty = FkToChar.objects.create(out=char_model_empty)
    fk_model_empty = FkToChar.objects.select_related('out').get(id=fk_model_empty.pk)
    self.assertEqual(fk_model_empty.out, char_model_empty)
