I want to use an existing python framework to develop an application on google appengine.
It should be quick and easy to start and support test driven development practices in an easy way.
Can you recommend a stack? What about django?
Additional Information:
There are several django ports, but the stackoverflow questions are already old. There were several django/appengine solutions, I do not know which one is currently leading.
But also other frameworks are interesting, not only django.
What also sounds good but is not a condition is the possibility to run the app on the framework and the appengine and maybe later run it on a self hosted (noSql-) version of this framework (which maybe could be django, or maybe somehting else).
UPDATE: This answer is now out of date.
For me the choice is djangoappengine.
It's a fork of the django project made specifically for no-sql databases like Google App Engine and MongoDB. The main benefit of it is that you get to piggy-back on all the cool stuff coming out of the django project, while also running on GAE's scalable architecture. Another benefit is that with djangoappengine, you can more easily move off of App Engine than if you used their API directly (although that is probably easier said than done).
There were rumors that Django would merge the changes into the mainline Django project, but it has not happened yet (as of May 2014).
Some relevant links: