def setUp(self):
     MEDIA_TYPES.clear()
    document = Cname


class App(Document):
    instances = fields.NumberField()
    label = fields.StringField()
    published = fields.BooleanField()
    user = fields.ForeignDocument(User, inline=True)
    postgres = fields.ForeignDocument(Postgres)
    cnames = fields.CollectionField(CnameCollection, inline=True)

    def uri(self):
        return 'app_uri'

# We clean the media-type/serializer mapping
MEDIA_TYPES.clear()


### The actual test classes
class when_a_serializer_gets_defined(unittest.TestCase):
    def setUp(self):
        MEDIA_TYPES.clear()

    def it_can_store_media_types(self):
        """Register media types and map them to serializers."""
        register_media_type('store/media', 'serializer')

        eq_(True, 'store/media' in MEDIA_TYPES)
        eq_('serializer', MEDIA_TYPES['store/media'])

    def it_registers_the_media_type(self):