Testing async delete with NDB

delete_tests.py

from google.appengine.ext.ndb import model, context, tasklets
from random import choice
import string
from werkzeug import Response

class Items(model.Model):
    user = model.StringProperty()
    
    @classmethod
    @tasklets.tasklet
    def delete_all_for_user(cls, user):
        yield model.delete_multi_async(cls.query(cls.user == user).fetch(keys_only=True, batch_size=100))

class Config(model.Model):
    user = model.StringProperty()
    stat_name = model.StringProperty()
    
    @classmethod
    @tasklets.tasklet
    def delete_all_for_user(cls, user):
        qry = cls.query(cls.user == user)
        yield qry.map_async(Stats.delete_all_for_config_callback, batch_size=100)
    
class Stats(model.Model):
    name = model.StringProperty()
    
    @classmethod
    @tasklets.tasklet
    def delete_all_for_config_callback(cls, ent):
        qry = cls.query(cls.name == ent.stat_name)
        #f = qry.map_async(lambda k: k.delete_async(), keys_only=True, batch_size=100)
        f = model.delete_multi_async(qry.fetch(keys_only=True, batch_size=100))
        yield f, ent.key.delete_async()
        
@context.toplevel
def test_delete_view(request):
    user = 'Test_User'
    if 'test' in request.args:
        yield Items.delete_all_for_user(user), Config.delete_all_for_user(user)
    else:
        #Setup
        model.put_multi([Items(user=user) for _ in xrange(200)])
        for _ in xrange(50):
            conf = Config(user=user)
            conf.stat_name = "".join([choice(string.ascii_letters) for _ in xrange(10)])
            model.put_multi([conf] + [Stats(name=conf.stat_name) for _ in xrange(10)])
    raise tasklets.Return(Response('Done'))