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NoseGAE: nose plugin for Google App Engine testing

Project description

NoseGAE: Nose for Google App Engine Testing

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NoseGAE is available from the cheeseshop and can be installed easiest
via ``pip install nosegae``. While the library is actively maintained,
no new features are being added at this time so development has
stagnated. If you want to work on the library, or just like to clone and
install you can use your choice of ``python install`` or
``python develop`` or even the ``pip`` equiv.


NoseGAE is a `nose <>`_
plugin that makes it easier to write functional and unit tests for
`Google App Engine <>`_ applications.

1. `What does it do? <#what-does-it-do>`_

1. `Functional tests <#functional-tests>`_
2. `Unit tests <#unit-tests>`_

2. `Configuring the TestBed <#configuring-the-testbed>`_

1. `Class Based Tests <#class-based-tests>`_
2. `Function Tests <#function-tests>`_
3. `Doctest <#doctest>`_

3. `Changes in 0.5.2 <#changes-in-052>`_
4. `Changes in 0.4.0 <#changes-in-040>`_

What does it do?

NoseGAE 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. The plugin also configures and initializes a TestBed
instance, your application\_id based off your ``app.yaml``, and sets the
proper paths using ``dev_appserver.fix_sys_path()``.

Functional tests

Consider the simple hello world application in ``examples/helloworld``:


import webapp2
from jinja2 import Environment

class Hello(webapp2.RequestHandler):
def get(self):
self.response.headers['Content-Type'] = 'text/plain'
env = Environment()
template = env.from_string("Hello {{ greeting }}!")

app = webapp2.WSGIApplication([('/', Hello)], debug=True)

And a simple functional test suite ``examples/helloworld/`` for
the application:


from webtest import TestApp
import unittest
import helloworld

app = TestApp(

class HelloWorldTest(unittest.TestCase):
def test_index(self):
"""Tests that the index page for the application

The page should be served as: Content-Type: text/plain
The body content should contain the string: Hello world!
response = app.get('/')
self.assertEqual(response.content_type, 'text/plain')
self.assertIn('Hello world!', response.body)

Without NoseGAE, the test fails.


helloworld$ nosetests --logging-level=ERROR
ERROR: Failure: ImportError (No module named webapp2)
Traceback (most recent call last):
File "/Users/Josh/Developer/Github/jj/lib/python2.7/site-packages/nose-1.3.4-py2.7.egg/nose/", line 414, in loadTestsFromName
addr.filename, addr.module)
File "/Users/Josh/Developer/Github/jj/lib/python2.7/site-packages/nose-1.3.4-py2.7.egg/nose/", line 47, in importFromPath
return self.importFromDir(dir_path, fqname)
File "/Users/Josh/Developer/Github/jj/lib/python2.7/site-packages/nose-1.3.4-py2.7.egg/nose/", line 94, in importFromDir
mod = load_module(part_fqname, fh, filename, desc)
File "/Users/Josh/Developer/Github/nosegae/examples/helloworld/", line 2, in <module>
import helloworld
File "/Users/Josh/Developer/Github/nosegae/examples/helloworld/", line 1, in <module>
import webapp2
ImportError: No module named webapp2

Ran 1 test in 0.075s

FAILED (errors=1)

With NoseGAE, they pass.


helloworld$ nosetests --logging-level=ERROR --with-gae
Ran 1 test in 0.264s


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 the ``examples/pets/`` file that includes some


from google.appengine.ext import ndb

class Pet(ndb.Model):
"""The Pet class provides storage for pets.

>>> # initialize testbed stubs
>>> testbed.init_memcache_stub()
>>> testbed.init_datastore_v3_stub()

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:

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

Or by a query that selects the pet:

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

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

>>> muffy_2 = muffy
>>> 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)
name = ndb.StringProperty(required=True)
type = ndb.StringProperty(required=True, choices=("cat", "dog", "bird", "fish", "monkey"))
breed = ndb.StringProperty()
age = ndb.IntegerProperty()
comments = ndb.TextProperty()
created = ndb.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.type, self.breed, self.age,
self.comments, self.created))

Without NoseGAE, the doctests fail.


pets$ nosetests --with-doctest --logging-level=ERROR
FAIL: Doctest: models.Pet
Traceback (most recent call last):
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/", line 2201, in runTest
raise self.failureException(self.format_failure(new.getvalue()))
AssertionError: Failed doctest test for models.Pet
File "/Users/Josh/Developer/Github/nosegae/examples/pets/", line 4, in Pet

File "/Users/Josh/Developer/Github/nosegae/examples/pets/", line 15, in models.Pet
Failed example:
muffy_key = muffy.put()
Exception raised:
Traceback (most recent call last):
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/", line 1289, in __run
compileflags, 1) in test.globs
File "<doctest models.Pet[2]>", line 1, in <module>
muffy_key = muffy.put()
File "/Applications/", line 3379, in _put
return self._put_async(**ctx_options).get_result()
File "/Applications/", line 325, in get_result
File "/Applications/", line 368, in _help_tasklet_along
value = gen.throw(exc.__class__, exc, tb)
File "/Applications/", line 810, in put
key = yield self._put_batcher.add(entity, options)
File "/Applications/", line 371, in _help_tasklet_along
value = gen.send(val)
File "/Applications/", line 343, in _put_tasklet
keys = yield self._conn.async_put(options, datastore_entities)
File "/Applications/", line 1801, in async_put
return make_put_call(base_req, pbs, extra_hook)
File "/Applications/", line 1784, in make_put_call
File "/Applications/", line 1310, in _make_rpc_call
rpc = self._create_rpc(config, service_name)
File "/Applications/", line 1205, in _create_rpc
rpc = apiproxy_stub_map.UserRPC(service_name, deadline, callback)
File "/Applications/", line 414, in __init__
self.__rpc = CreateRPC(service, stubmap)
File "/Applications/", line 68, in CreateRPC
assert stub, 'No api proxy found for service "%s"' % service
AssertionError: No api proxy found for service "datastore_v3"

With NoseGAE, they pass.


pets$ nosetests --with-doctest --with-gae
Ran 1 test in 0.228s


Configuring the TestBed

NoseGAE automatically configures your ``TestBed`` instance for you and
then enables any stubs that you may need for your tests to pass. There
are two ways to enable and configure your stubs. The first and most
flexible way is to directly initialize the stub(s) on the ``TestBed``
instance injected into your test case. The second, and simpler way, is
to set the ``nosegae_*`` and optional ``nosegae_*_kwargs`` attributes on
your test case and let NoseGAE configure them for you. The following
three sections describe how to use the ``TestBed`` in your own tests.

Class Based Tests

The simplest of use cases is when your test class extends
``unittest.TestCase``. The NoseGAE plugin injects an attribute named
``testbed`` to the instance of your test class and configures it based
upon any attributes matching the convention ``nosegae_<stubname>`` and

This test uses the assigned ``testbed`` attribute to manually configure
each test.


class MyTest(unittest.TestCase):
def test_using_memcache(self):
"""Unit test using memcache"""
from google.appengine.api import memcache
memcache.set('test', True, 30)

def test_using_taskqueue(self):
"""Unit test using the taskqueue"""
from google.appengine.api import taskqueue
task_url = '/some/task'
taskqueue_stub = self.testbed.get_stub('taskqueue')
tasks = taskqueue_stub.get_filtered_tasks(url=task_url)
self.assertEqual(1, len(tasks))
self.assertEqual(task_url, tasks[0].url)

The following test case shows how to write a test that uses the
datastore stub based on the simple configuration method using
``nosegae_<stubname>`` and ``nosegae_<stubname>_kwargs``.


class DataTest(unittest.TestCase):
# enable the datastore stub
nosegae_datastore_v3 = True

def test_get_entity(self):
"""Naively tests that we can fetch an entity from the datastore"""
entity = MyModel.query().get()

Function Tests

This test case uses the ``testbed`` instance assigned to the function to
manually configure any needed stubs. See


def test_index():
# test_index.testbed is assigned by the NoseGAE plugin
test_index.testbed.init_taskqueue_stub(task_retry_seconds=42, root_path=os.path.dirname(__file__))
# Assume the `/` route fires off a task queue and should pass without exceptions
app = TestApp(
response = app.get('/')
assert 'Hello world!' in str(response)

The following test shows how to use the simple method while passing
kwargs to the taskqueue stub's initialization method. See
``examples/issue42_task-queue`` for full example code.


def test_index():
# Assume the `/` route fires off a task queue and should pass without exceptions
app = TestApp(app)
response = app.get('/')
assert 'Hello world!' in str(response)

# Enable any stubs needed as attributes off of the test function

# NoseGAE looks for queue.yaml in the root of the
# application when nosegae_taskqueue is True
test_index.nosegae_taskqueue = True

# ...or you can manually set the path and any additional arguments with the kwargs attribute
test_index.nosegae_taskqueue_kwargs = dict(task_retry_seconds=42, root_path=os.path.dirname(__file__))


Doctests are a whole other beast. They still work but all ``TestBed``
configuration has to be done manually. NoseGAE uses the `nose doctest
plugin <>`_
to inject a global variable named ``testbed`` into your doctest scope
that contains the current active ``TestBed`` instance. See
``examples/pets/`` for full example.

\`\`\`python class Pet(ndb.Model): """The Pet class provides storage for


>>> # Initialize stubs using the injected testbed instance
>>> testbed.init_memcache_stub()
>>> testbed.init_datastore_v3_stub()

You can create a pet:
>>> muffy = Pet(name=u'muffy', type=u'dog', breed=u"Shi'Tzu")
>>> muffy_key = muffy.put()
name = ndb.StringProperty(required=True)
type = ndb.StringProperty(required=True, choices=("cat", "dog", "bird", "fish", "monkey"))
breed = ndb.StringProperty()

\`\`\` ## Changes in 0.5.2

The 0.5.2 release introduces preliminary modules support by allowing
multiple yaml or paths sent to the ``--gae-application`` command line


nosetests --with-gae \

Changes in 0.4.0

The 0.4.0 release is a major rewrite to support ``dev_appserver2``. This
release introduced two important changes listed below.

Sandbox is gone

Due to changes in the sandboxing mechanisms in dev\_appserver2, it isn't
possible for NoseGAE to simulate the deployed environment any longer.
The sandboxing feature had to be removed since there is no longer any
way to toggle it between ``nose``s own internal workings.

This means that certain tests may pass locally but the code in question
will fail in production due to restricted modules and functions. As of
now there is no workaround but pull requests are welcome!

Testbed is set up for you

The new plugin automatically sets up the initial
``google.appengine.ext.testbed.Testbed`` instance and injects it into
your test cases for you.

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