# Testing MPTT models

## Using testing generators

Using testing generators such as `model_bakery` is causing random tree fields values, which can cause unexpected behavior. To prevent that the `django-mptt.MPTTModel` will throw an Exception if made through model_bakery in test environment unless the `MPTT_ALLOW_TESTING_GENERATORS` setting is set to True.

You can set the `MPTT_ALLOW_TESTING_GENERATORS` setting to True in your Django testing settings.py file or by the `@override_settings` decorator for particular test. You would probably also have to use recipe and explicitly set the appropriate fields for the model.

    from django.test import override_settings
    from baker.recipe import Recipe

    @override_settings(MPTT_ALLOW_TESTING_GENERATORS=True)
    def test_mptt_allow_testing_generators(self):
        my_model_recipe = Recipe(MyMPTTModel, lft=None, rght=None)
        test_model_instance = my_model_recipe.make()