Functional testing with isolated ZODBs in Pyramid

layer.py

import os

from plone.testing import Layer
from plone.testing import zodb
from pyramid.request import Request
from webtest import TestApp
from ZODB.DB import DB

from YOURAPP import factory


def pushDemoStorage(app):
    db = app.registry._zodb_databases['']
    stacked = zodb.stackDemoStorage(db, name='')
    app.registry._zodb_databases[''] = stacked

def popDemoStorage(app):
    db = app.registry._zodb_databases['']
    base = DB(db.storage.base)
    app.registry._zodb_databases[''] = base

class BaseFunctionalLayer(Layer):
    
    def setUp(self):
        pushDemoStorage(self['app'])
        self.__layer_connection = self['app'].registry._zodb_databases[''].open()
        self['layer_root'] = self.__layer_connection.root()['app_root']
    
    def tearDown(self):
        self.__layer_connection.close()
        popDemoStorage(self['app'])
    

class BaseWebtestLayer(BaseFunctionalLayer):

    def setUp(self, settings={}, locale="en"):
        settings["pyramid.default_locale_name"] = locale
        settings["zodbconn.uri"] = "memory://fake"
        self['app'] = factory({}, **settings)
        self['route_url'] = self.route_url
        self['translate_string'] = self.translate_string
        self.create_browser()

    def create_browser(self):
        self['browser'] = TestApp(self['app'])
    
    def tearDown(self):
        self['browser'] = self['app'] = self.group_id = None
    
    def testSetUp(self):
        pushDemoStorage(self['app'])
        self.__test_connection = self['app'].registry._zodb_databases[''].open()
        self['root'] = self.__test_connection.root()['app_root']
    
    def testTearDown(self):
        self.__test_connection.close()
        del self['root']
        popDemoStorage(self['app'])

    def route_url(self, route_name, **mapping):
        return self['app'].routes_mapper.generate(route_name, mapping)
    

FUNCTIONAL_LAYER = BaseWebtestLayer()