Keystone Mocking issue...

implementation.py

import base64
import binascii

import simplejson as json
import redis

from keystoneclient.v2_0 import client as keystonev2_client
import keystone.exceptions
import keystoneclient.access as keystone_access

LOG = logging.getLogger(__name__)


def _send_data_to_cache(redis_client, url, access_info):
    """Stores the authentication data to memcache

    :param redis_client: redis.Redis object connected to the redis cache
    :param url: URL used for authentication
    :param access_info: keystoneclient.access.AccessInfo containing
        the auth data

    :returns: True on success, otherwise False
    """
    try:
        # Convert the access_info dictionary into a string for storage
        data = {}
        data.update(access_info)
        cache_data = json.dumps(data)
        cache_data_utf8 = cache_data.encode(encoding='utf-8', errors='strict')
        cache_data_b64 = base64.b64encode(cache_data_utf8)

        tenant = access_info.tenant_id
        token = access_info.auth_token

        # Guild the cache key and store the value
        # Use the token's expiration time for the cache expiration
        cache_key = _tuple_to_cache_key((tenant, token, url))
        redis_client.set(cache_key, cache_data)
        redis_client.pexpire(cache_key, access_info.expires)

        return True

    except Exception as ex:
        msg = _('Failed to cache the data - Exception: %(s_except)s') % {
            's_except': ex,
        }
        LOG.error(msg)
        return False

def _retrieve_data_from_keystone(redis_client, url, tenant, token):
    """Retrieve the authentication data from OpenStack Keystone

    :param redis_client: redis.Redis object connected to the redis cache
    :param url: Keystone Identity URL to authenticate against
    :param tenant: tenant id of user data to retrieve
    :param token: auth_token for the tenant_id

    :returns: a keystoneclient.access.AccessInfo on success or None on error
    """
    try:
        keystone = keystonev2_client.Client(tenant_id=tenant, token=token, auth_url=url)

    except Exception as ex:
        msg = _('Failed to retrieve Keystone client - %(s_except)s') % {
            's_except': ex
        }
        LOG.debug(msg)
        return None

    # Now try to authenticate the user and get the user information using
    # only the data provided, no special administrative tokens required
    try:
        access_info = keystone.get_raw_token_from_identity_service(
            auth_url=url, tenant_id=tenant, token=token)

        # cache the data so it is easier to access next time
        _send_data_to_cache(redis_client, url, access_info)

        return access_info

    except keystoneclient.exceptions.AuthorizationFailure as ex:
        # Provided data was invalid
        msg = _('Failed to authenticate against %(s_url) - %(s_except)s') % {
            's_url' : auth_url,
            's_except' : ex
        }
        LOG.debug( msg )
        return None

test.py

from __future__ import division
from wsgiref import simple_server

import fakeredis
import mock
import base64
import binascii
import simplejson as json
import keystoneclient.exceptions
from keystoneclient.access import AccessInfoV2

from eom import auth
import tests
from . import util
from .mocks import servicecatalog


def fakeredis_connection():
    return fakeredis.FakeRedis()


def run_server(app, host, port):
    httpd = simple_server.make_server(host, port, app)
    httpd.serve_forever()


class TestAuth(tests.util.TestCase):

    def setUp(self):
        super(TestAuth, self).setUp()
        redis_client = fakeredis_connection()
        self.auth = auth.wrap(tests.util.app, redis_client)
        self.test_url = '/v2/vault'

        #config = auth.CONF['eom:auth']
        #self.runtime_url = config['auth_url']
        #config['auth_url'] = 'localhost/v2'

    def tearDown(self):
        super(TestAuth, self).tearDown()
        redis_client = fakeredis_connection()
        redis_client.flushall()

        #config = auth.CONF['eom:auth']
        #config['auth_url'] = self.runtime_url

    def test_retrieve_keystone_stone(self):
        url = 'myurl'
        tenant_id = '789012345'
        token = 'abcdefABCDEF'

        redis_client = fakeredis_connection()

        with mock.patch(
            'keystoneclient.v2_0.client.Client', autospec=True) as MockKeystoneClient:
            MockKeystoneClient.side_effect = Exception('Mock - invalid client object')
            keystone_create_error = auth._retrieve_data_from_keystone(redis_client, url, tenant_id, token)
            self.assertIsNone(keystone_create_error)

        with mock.patch(
            'keystoneclient.v2_0.client.Client', autospec=True) as MockKeystoneClient:
            reload(keystoneclient)

            # Fail to get a valid Client object
            # Note: Client() uses the requests package to do an auth;
            #   on failure it is the requests module that fails.
            MockKeystoneClient.get_raw_token_from_identity_service = mock.Mock(side_effect = \
                keystoneclient.exceptions.AuthorizationFailure('mock Keystone error'))
            keystone_error = auth._retrieve_data_from_keystone(redis_client, url, tenant_id, token)
            self.assertIsNone(keystone_error)
            # Note: This fails because the side effect on get_raw_token_from_identity_service is not happening. Why???

Lines 55-59 pass.

Lines 61-73 fail due to a mocking issue. I am trying to figure out why it is not raising the Exception like it should. I've tried a number of methods, including a new mock.patch on the function, or setting the function to a function that simply raises the exception without any luck.

What am I doing wrong?

(Note: I can provide more of the code if required)

Here's the run:
(py27)bmeyer@ben-linux-ubuntu:~/rackspace/envs/eom$ nosetests tests.test_auth
tests.test_auth.TestAuth.test_cache_key ... ok
tests.test_auth.TestAuth.test_retrieve_cache_data ... ok
tests.test_auth.TestAuth.test_retrieve_keystone_stone ... FAIL
tests.test_auth.TestAuth.test_store_data_to_cache ... ok

FAIL: tests.test_auth.TestAuth.test_retrieve_keystone_stone

_StringException: Traceback (most recent call last):
File "/home/bmeyer/rackspace/envs/eom/tests/test_auth.py", line 231, in test_retrieve_keystone_stone
self.assertIsNone(keystone_error)
File "/home/bmeyer/rackspace/envs/eom/.tox/py27/local/lib/python2.7/site-packages/testtools/testcase.py", line 353, in assertIsNone
self.assertThat(observed, matcher, message)
File "/home/bmeyer/rackspace/envs/eom/.tox/py27/local/lib/python2.7/site-packages/testtools/testcase.py", line 423, in assertThat
raise mismatch_error
MismatchError: is not:
reference = None
actual =

-------------------- >> begin captured logging << --------------------
eom.auth: DEBUG: Failed to retrieve Keystone client - Mock - invalid client object
eom.auth: ERROR: Failed to cache the data - Exception: sequence item 0: expected string, MagicMock found
--------------------- >> end captured logging << ---------------------

Note: the eom.auth.ERROR is generated by line 43 in implementation.py because the parameter access_info in line 77 is a mock object due to the exception not happening