Mock seamicroclient lib in unit tests if not present

Mock the python-seamicroclient library from within ironic/tests/drivers
so that test_seamicro.py can import ironic/drivers/modules/seamicro.py
and run the unit tests on it, even when the external library is not
present.

Change-Id: I4f2cd75b2c64a5a280a5d45d5cea058fd432815b
Closes-bug: #1312321

3 files changed, 71 insertions, 7 deletions

diff --git a/ironic/tests/drivers/__init__.py b/ironic/tests/drivers/__init__.py
index e69de29bb..0640dde8d 100644
--- a/ironic/tests/drivers/__init__.py
+++ b/ironic/tests/drivers/__init__.py
@@ -0,0 +1,21 @@
+# Copyright 2014 Hewlett-Packard Development Company, L.P.
+# All Rights Reserved.
+#
+#    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.
+
+# NOTE(deva): since __init__ is loaded before the files in the same directory,
+#             and some third-party driver tests may need to have their
+#             external libraries mocked, we load the file which does that
+#             mocking here -- in the __init__.
+
+from ironic.tests.drivers import third_party_driver_mocks   # noqa
diff --git a/ironic/tests/drivers/test_seamicro.py b/ironic/tests/drivers/test_seamicro.py
index cc47bbaa8..6620ed6f8 100644
--- a/ironic/tests/drivers/test_seamicro.py
+++ b/ironic/tests/drivers/test_seamicro.py
@@ -15,6 +15,7 @@
 import uuid
 
 import mock
+from seamicroclient import exceptions as seamicro_client_exception
 
 from ironic.common import driver_factory
 from ironic.common import exception
@@ -23,7 +24,6 @@ from ironic.conductor import task_manager
 from ironic.db import api as dbapi
 from ironic.drivers.modules import seamicro
 from ironic.openstack.common import context
-from ironic.openstack.common import importutils
 from ironic.tests import base
 from ironic.tests.conductor import utils as mgr_utils
 from ironic.tests.db import base as db_base
@@ -32,10 +32,6 @@ from ironic.tests.objects import utils as obj_utils
 
 INFO_DICT = db_utils.get_test_seamicro_info()
 
-seamicroclient = importutils.try_import("seamicroclient")
-if seamicroclient:
-    from seamicroclient import exceptions as seamicro_client_exception
-
 
 class Fake_Server():
     def __init__(self, active=False, *args, **kwargs):
@@ -264,8 +260,6 @@ class SeaMicroPowerDriverTestCase(db_base.DbTestCase):
 
     def setUp(self):
         super(SeaMicroPowerDriverTestCase, self).setUp()
-        if not seamicroclient:
-            self.skipTest("Seamicroclient library not found")
         mgr_utils.mock_the_extension_manager(driver='fake_seamicro')
         self.driver = driver_factory.get_driver('fake_seamicro')
         self.node = obj_utils.create_test_node(self.context,
diff --git a/ironic/tests/drivers/third_party_driver_mocks.py b/ironic/tests/drivers/third_party_driver_mocks.py
new file mode 100644
index 000000000..a1b5d808e
--- /dev/null
+++ b/ironic/tests/drivers/third_party_driver_mocks.py
@@ -0,0 +1,49 @@
+# Copyright 2014 Hewlett-Packard Development Company, L.P.
+# All Rights Reserved.
+#
+#    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.
+
+"""This module detects whether third-party libraries, utilized by third-party
+drivers, are present on the system. If they are not, it mocks them and tinkers
+with sys.modules so that the drivers can be loaded by unit tests, and the unit
+tests can continue to test the functionality of those drivers without the
+respective external libraries' actually being present.
+
+Any external library required by a third-party driver should be mocked here.
+Current list of mocked libraries:
+    seamicroclient
+"""
+
+import sys
+
+import mock
+
+from ironic.openstack.common import importutils
+
+
+# attempt to load the external 'seamicroclient' library, which is
+# required by the optional drivers.modules.seamicro module
+seamicroclient = importutils.try_import("seamicroclient")
+if not seamicroclient:
+    smc = mock.Mock()
+    smc.client = mock.Mock()
+    smc.exceptions = mock.Mock()
+    smc.exceptions.ClientException = Exception
+    sys.modules['seamicroclient'] = smc
+    sys.modules['seamicroclient.client'] = smc.client
+    sys.modules['seamicroclient.exceptions'] = smc.exceptions
+
+# if anything has loaded the seamicro driver yet, reload it now that
+# the external library has been mocked
+if 'ironic.drivers.modules.seamicro' in sys.modules:
+    reload(sys.modules['ironic.drivers.modules.seamicro'])