  
          s = DecimalSerializer(data={'decimal_field': '12345.6'})
  
          self.assertFalse(s.is_valid())
          self.assertEqual(s.errors,  {'decimal_field': ['Ensure that there are no more than 4 digits in total.']}) 
</s> remove     ManyToManyModel, Person, ReadOnlyManyToManyModel, Photo)
 </s> add     ManyToManyModel, Person, ReadOnlyManyToManyModel, Photo, SeveralChoicesModel)
  
          s = DecimalSerializer(data={'decimal_field': '12345.6'})
  
          self.assertFalse(s.is_valid())

keep keep keep keep replace
 Adding `BLANK_CHOICE_DASH` as a choice if the model's field isn't required 
rest_framework/tests/fields.py