Functional tests

The plugin sets up the GAE development environment before your test run. This means that you can easily write functional tests for your application without having to actually start the dev server and test over http. Note however that this kind of testing requires that your application be a wsgi application.

Consider a simple hello world wsgi application:

import wsgiref.handlers
from google.appengine.ext import webapp

class Hello(webapp.RequestHandler):
    def get(self):
        self.response.headers['Content-Type'] = 'text/plain'
        self.response.out.write('Hello world!')

def application():
    return webapp.WSGIApplication([('/', Hello)], debug=True)
        
def main():
    wsgiref.handlers.CGIHandler().run(application())

if __name__ == '__main__':
    main()

And a simple functional test suite for the application:

from webtest import TestApp
from helloworld import application

app = TestApp(application())

def test_index():
    response = app.get('/')
    assert 'Hello world!' in str(response)

The important part to note is the application() function that returns the application. That function provides a way get the application under test and call it directly, without having to pass through the dev app server. And that's all you need to do for basic functional testing.

nosetests -v --with-gae

test.test_index ... ok
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Ran 1 test in ...s
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OK

Unit tests

Functional tests are only one kind of test, of course. What if you want to write unit tests for your data models? Normally, you can't use your models at all outside of the dev environment, because the Google App Engine datastore isn't available. However, since the NoseGAE plugin sets up the development environment around your test run, you can use models directly in your tests.

Consider a simple models file that includes some doctests:

from google.appengine.ext import db

class Pet(db.Model):
    """
    The Pet class provides storage for pets. You can create a pet:

    >>> muffy = Pet(name=u'muffy', type=u'dog', breed=u"Shi'Tzu")
    >>> muffy # doctest: +ELLIPSIS
    Pet(name=u'muffy', type=u'dog', breed=u"Shi'Tzu", ...)
    >>> muffy_key = muffy.put()

    Once created, you can load a pet by its key:

    >>> Pet.get(muffy_key) # doctest: +ELLIPSIS
    Pet(name=u'muffy', type=u'dog', breed=u"Shi'Tzu", ...)

    Or by a query that selects the pet:

    >>> list(Pet.all().filter('type = ', 'dog')) # doctest: +ELLIPSIS
    [Pet(name=u'muffy', ...)]

    To modify a pet, change one of its properties and ``put()`` it again.

    >>> muffy_2 = _[0]
    >>> muffy_2.age = 10
    >>> muffy_key_2 = muffy_2.put()

    The pet's key doesn't change when it is updated.

    >>> bool(muffy_key == muffy_key_2)
    True
    """
    name = db.StringProperty(required=True)
    type = db.StringProperty(required=True,
                             choices=set(["cat", "dog", "bird",
                                          "fish", "monkey"]))
    breed = db.StringProperty()
    age = db.IntegerProperty()
    comments = db.TextProperty()
    created = db.DateTimeProperty(auto_now_add=True, required=True)

    def __repr__(self):
        return ("Pet(name=%r, type=%r, breed=%r, age=%r, "
                "comments=%r, created=%r)" %
                (self.name, self.type, self.breed, self.age,
                 self.comments, self.created))

Without NoseGAE, the doctests fail.

nosetests -v --with-doctest

Failure: ImportError (No module named google.appengine.ext) ... ERROR
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======================================================================
ERROR: Failure: ImportError (No module named google.appengine.ext)
----------------------------------------------------------------------
Traceback (most recent call last):
...
ImportError: No module named google.appengine.ext
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----------------------------------------------------------------------
Ran 1 test in ...s
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FAILED (errors=1)

With NoseGAE, they pass.

nosetests -v --with-doctest --with-gae

Doctest: models.Pet ... ok
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----------------------------------------------------------------------
Ran 1 test in ...s
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OK