          model = TimestampedModel
  
  
  class ReadOnlyFieldTests(TestCase):
      def test_auto_now_fields_read_only(self):
          """
          auto_now and auto_now_add fields should be readonly by default.
 
</s> remove         return Field()
 </s> add         return self.get_field(model_field) </s> remove         if not model_field.editable:
 </s> add         if isinstance(model_field, models.AutoField) or not model_field.editable:
class CharPrimaryKeyModelSerializer(serializers.ModelSerializer):
    class Meta:
        model = CharPrimaryKeyModel


          model = TimestampedModel
  
  
class CharPrimaryKeyModelSerializer(serializers.ModelSerializer):
    class Meta:
        model = CharPrimaryKeyModel


  class ReadOnlyFieldTests(TestCase):
      def test_auto_now_fields_read_only(self):
          """
          auto_now and auto_now_add fields should be readonly by default.
keep keep add keep keep keep keep
 PK fields should only be read-only if they are an AutoField.  Fixes #563 
rest_framework/tests/fields.py