An easy way to test your App Engine Python applications

1. TDD with App Engine and
Python
the easy way

2. Show of hands
● Who already uses App Engine with Python?
● Who does TDD with App Engine and
Python?
● Who writes tests?

3. O que é o Google App Engine

4. O que é o Google App Engine

5. O que é o Google App Engine

6. What is Google App Engine
● A PaaS - platform as a service
● Specific APIs and libraries
o but can run Django, Flask etc adapted apps
● You don't worry about the server
● Google's team manages them for you
● A local development environment
● Deployment using the SDK (or git - for Java)

7. What else is in Google App Engine
● Automagic spin-up and spin-down of servers
● Pay-as-you-go
● Datastore (NoSQL) + Google Cloud SQL
● Queues - for asynchronous tasks
● NDB - asynchronous data access (and
more)
● Authentication
● A framework that encourages good practices

8. More?
● A management interface
● You can keep multiple versions deployed
o And split traffic between them
● A brand-new management interface
o Integrated with the other cloud products family

9. What we had before?
● GAEUnit
o Deploys testing code to production
o Does it still work?
● SDK testbed
o Batteries not included
● NoseGAE, pytest-gae
o Some batteries included
● ?

10. Why build another one?
● Include more batteries
● Being opinionated can be good
o Conventions over configuration helps newcomers
● Some things are missing from the vanilla
SDK
o Examples
o The way Django uses its fixtures is amazing

11. Why build another one? (continued)
● Virtualenvs are cool
o To break the system Python is always painful
o Built-in Python may not be an option
● If it's hard to test, people won't
o Laziness is one of the virtues of a programmer (even
if, in this case, it may not be)
● A little bit of support goes a long way

12. What was done?
● A skeleton project (on GitHub)
● Creates a virtualenv
● Runs sanity tests
● Loads data from a JSON file
● Assemble everything with a Makefile
● Tests do not rely on the development server
● You can run ipdb (in your tests)!

13. How do you use it?
Demo
1. git clone
o git@github.com:rbanffy/testable_appengine.git
2. make venv
3. nosetests (or py.test)

14. O que falta fazer
● Importar hierarquias de objetos para testes
● Tornar mais fácil usar em projetos já em
andamento
o Sobretudo manter o maquinário atualizado
o Se bem que isso pode nem ser importante
● Precisamos de mais usuários
o Que dêem mais palpites

15. Questions?

16. Contact
about.me/rbanffy
@rbanffy
https://github.com/rbanffy/testable_appengine