glance policy unit tests should use a simple mock instead of a FakePolicyEnforcer

[Nikhil Komawar]

Currently, an example test in the unit test policy looks like:-

class TestImagePolicy(test_utils.BaseTestCase):
    def setUp(self):
        self.image_stub = ImageStub(UUID1)
        self.image_repo_stub = ImageRepoStub()
        self.image_factory_stub = ImageFactoryStub()
        self.policy = unit_test_utils.FakePolicyEnforcer() <- this could be a mock instead
        super(TestImagePolicy, self).setUp()

    def test_publicize_image_not_allowed(self):
        rules = {"publicize_image": False} <- this does not represent how rules are formatted
        self.policy.set_rules(rules)
        image = glance.api.policy.ImageProxy(self.image_stub, {}, self.policy)
        self.assertRaises(exception.Forbidden,
                          setattr, image, 'visibility', 'public')
        self.assertEquals(image.visibility, 'private')

----
this sample piece of code would work instead
        self.policy = mock.Mock()
        self.policy.enforce = mock.Mock()
        self.policy.enforce.side_effect = exception.Forbidden()

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/53451
Committed: http://github.com/openstack/glance/commit/0c1f60d06bae8e571c7accb596ad9268ac066c40
Submitter: Jenkins
Branch: master

commit 0c1f60d06bae8e571c7accb596ad9268ac066c40
Author: Nikhil Komawar <email address hidden>
Date: Wed Oct 23 16:34:48 2013 -0400

    Use mock in test_policy

    FakePolicyEnforcer is trying to imitate the real policy enforcer.
    We don't need it in the test_policy tests.

    fixes bug 1243902

    Change-Id: Id82d09dc9aafbf57b6fc968ae1ded944b8d64229