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# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2012 OpenStack LLC
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import unittest2 as unittest
import uuid
from keystone.common import dependency
class TestDependencyInjection(unittest.TestCase):
def tearDown(self):
dependency.reset()
super(TestDependencyInjection, self).tearDown()
def test_dependency_injection(self):
class Interface(object):
def do_work(self):
assert False
@dependency.provider('first_api')
class FirstImplementation(Interface):
def do_work(self):
return True
@dependency.provider('second_api')
class SecondImplementation(Interface):
def do_work(self):
return True
@dependency.requires('first_api', 'second_api')
class Consumer(object):
def do_work_with_dependencies(self):
assert self.first_api.do_work()
assert self.second_api.do_work()
# initialize dependency providers
first_api = FirstImplementation()
second_api = SecondImplementation()
# ... sometime later, initialize a dependency consumer
consumer = Consumer()
# the expected dependencies should be available to the consumer
self.assertIs(consumer.first_api, first_api)
self.assertIs(consumer.second_api, second_api)
self.assertIsInstance(consumer.first_api, Interface)
self.assertIsInstance(consumer.second_api, Interface)
consumer.do_work_with_dependencies()
def test_dependency_provider_configuration(self):
@dependency.provider('api')
class Configurable(object):
def __init__(self, value=None):
self.value = value
def get_value(self):
return self.value
@dependency.requires('api')
class Consumer(object):
def get_value(self):
return self.api.get_value()
# initialize dependency providers
api = Configurable(value=True)
# ... sometime later, initialize a dependency consumer
consumer = Consumer()
# the expected dependencies should be available to the consumer
self.assertIs(consumer.api, api)
self.assertIsInstance(consumer.api, Configurable)
self.assertTrue(consumer.get_value())
def test_dependency_consumer_configuration(self):
@dependency.provider('api')
class Provider(object):
def get_value(self):
return True
@dependency.requires('api')
class Configurable(object):
def __init__(self, value=None):
self.value = value
def get_value(self):
if self.value:
return self.api.get_value()
# initialize dependency providers
api = Provider()
# ... sometime later, initialize a dependency consumer
consumer = Configurable(value=True)
# the expected dependencies should be available to the consumer
self.assertIs(consumer.api, api)
self.assertIsInstance(consumer.api, Provider)
self.assertTrue(consumer.get_value())
def test_inherited_dependency(self):
class Interface(object):
def do_work(self):
assert False
@dependency.provider('first_api')
class FirstImplementation(Interface):
def do_work(self):
return True
@dependency.provider('second_api')
class SecondImplementation(Interface):
def do_work(self):
return True
@dependency.requires('first_api')
class ParentConsumer(object):
def do_work_with_dependencies(self):
assert self.first_api.do_work()
@dependency.requires('second_api')
class ChildConsumer(ParentConsumer):
def do_work_with_dependencies(self):
assert self.second_api.do_work()
super(ChildConsumer, self).do_work_with_dependencies()
# initialize dependency providers
first_api = FirstImplementation()
second_api = SecondImplementation()
# ... sometime later, initialize a dependency consumer
consumer = ChildConsumer()
# dependencies should be naturally inherited
self.assertEqual(
ParentConsumer._dependencies,
set(['first_api']))
self.assertEqual(
ChildConsumer._dependencies,
set(['first_api', 'second_api']))
self.assertEqual(
consumer._dependencies,
set(['first_api', 'second_api']))
# the expected dependencies should be available to the consumer
self.assertIs(consumer.first_api, first_api)
self.assertIs(consumer.second_api, second_api)
self.assertIsInstance(consumer.first_api, Interface)
self.assertIsInstance(consumer.second_api, Interface)
consumer.do_work_with_dependencies()
def test_unresolvable_dependency(self):
@dependency.requires(uuid.uuid4().hex)
class Consumer(object):
pass
with self.assertRaises(dependency.UnresolvableDependencyException):
Consumer()
dependency.resolve_future_dependencies()
def test_circular_dependency(self):
p1_name = uuid.uuid4().hex
p2_name = uuid.uuid4().hex
@dependency.provider(p1_name)
@dependency.requires(p2_name)
class P1(object):
pass
@dependency.provider(p2_name)
@dependency.requires(p1_name)
class P2(object):
pass
p1 = P1()
p2 = P2()
dependency.resolve_future_dependencies()
self.assertIs(getattr(p1, p2_name), p2)
self.assertIs(getattr(p2, p1_name), p1)
def test_reset(self):
# Can reset the registry of providers.
p_id = uuid.uuid4().hex
@dependency.provider(p_id)
class P(object):
pass
p_inst = P()
self.assertIs(dependency.REGISTRY[p_id], p_inst)
dependency.reset()
self.assertFalse(dependency.REGISTRY)
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