Fix Windows support for the unit tests

We've been running the unit tests mostly on Linux as part of the
CI test jobs.

On Windows, some of the tests fail mostly due to the WMI lib not
being mocked correctly. This issue is addressed by this change.

Change-Id: Ib4de3d262a7cf98a552f6234f6561d6c87b2067d

os_win/tests/unit/test_base.py

@@ -19,6 +19,8 @@ from oslotest import base
 from oslotest import mock_fixture
 from six.moves import builtins
 
+import os
+
 from os_win import exceptions
 from os_win.utils import baseutils
 
@@ -66,6 +68,13 @@ class OsWinBaseTestCase(BaseTestCase):
         mock_os = mock.MagicMock(Version='6.3.0')
         self._mock_wmi.WMI.return_value.Win32_OperatingSystem.return_value = (
             [mock_os])
-        wmi_patcher = mock.patch.object(builtins, 'wmi', create=True,
-                                        new=self._mock_wmi)
+
+        if os.name == 'nt':
+            # The wmi module is expected to exist and by the time this runs,
+            # the tested module will have imported it already.
+            wmi_patcher = mock.patch('wmi.WMI', new=self._mock_wmi.WMI)
+        else:
+            # The wmi module doesn't exist, we'll have to "create" it.
+            wmi_patcher = mock.patch.object(builtins, 'wmi', create=True,
+                                            new=self._mock_wmi)
         wmi_patcher.start()

os_win/tests/unit/test_utilsfactory.py

@@ -126,7 +126,8 @@ class TestHyperVUtilsFactory(test_base.OsWinBaseTestCase):
             expected_class=diskutils.DiskUtils,
             class_type='diskutils')
 
-    def test_get_clusterutils(self):
+    @mock.patch.object(clusterutils.ClusterUtils, '_init_hyperv_conn')
+    def test_get_clusterutils(self, mock_init_conn):
         self._check_get_class(
             expected_class=clusterutils.ClusterUtils,
             class_type='clusterutils')

os_win/tests/unit/utils/compute/test_clusterutils.py

@@ -43,7 +43,8 @@ class ClusterUtilsTestCase(test_base.OsWinBaseTestCase):
     _FAKE_VM_NAME = 'instance-00000001'
     _FAKE_RESOURCEGROUP_NAME = 'Virtual Machine %s' % _FAKE_VM_NAME
 
-    def setUp(self):
+    @mock.patch.object(clusterutils.ClusterUtils, '_init_hyperv_conn')
+    def setUp(self, mock_get_wmi_conn):
         super(ClusterUtilsTestCase, self).setUp()
         self._clusterutils = clusterutils.ClusterUtils()
         self._clusterutils._conn_cluster = mock.MagicMock()

os_win/tests/unit/utils/test_baseutils.py

@@ -15,6 +15,8 @@
 import mock
 import six
 
+import imp
+
 from os_win.tests.unit import test_base
 from os_win.utils import baseutils
 
@@ -26,6 +28,7 @@ class BaseUtilsTestCase(test_base.OsWinBaseTestCase):
         super(BaseUtilsTestCase, self).setUp()
         self.utils = baseutils.BaseUtils()
         self.utils._conn = mock.MagicMock()
+        mock.patch.object(imp, 'load_source').start()
 
     @mock.patch.object(baseutils, 'wmi', create=True)
     def test_get_wmi_obj(self, mock_wmi):
@@ -80,6 +83,7 @@ class BaseUtilsVirtTestCase(test_base.OsWinBaseTestCase):
         self.utils = baseutils.BaseUtilsVirt()
         self.utils._conn_attr = mock.MagicMock()
         baseutils.BaseUtilsVirt._os_version = None
+        mock.patch.object(imp, 'load_source').start()
 
     @mock.patch.object(baseutils.BaseUtilsVirt, '_get_wmi_conn')
     def test_conn(self, mock_get_wmi_conn):
@@ -97,21 +101,20 @@ class BaseUtilsVirtTestCase(test_base.OsWinBaseTestCase):
         self.assertEqual(expected, self.utils._vs_man_svc)
         self.assertEqual(expected, self.utils._vs_man_svc_attr)
 
-    @mock.patch.object(baseutils, 'imp')
     @mock.patch.object(baseutils, 'wmi', create=True)
-    def test_vs_man_svc_2012(self, mock_wmi, mock_imp):
+    def test_vs_man_svc_2012(self, mock_wmi):
         baseutils.BaseUtilsVirt._old_wmi = None
         mock_os = mock.MagicMock(Version='6.2.0')
         mock_wmi.WMI.return_value.Win32_OperatingSystem.return_value = [
             mock_os]
         fake_module_path = '/fake/path/to/module'
         mock_wmi.__path__ = [fake_module_path]
-        old_conn = mock_imp.load_source.return_value.WMI.return_value
+        old_conn = imp.load_source.return_value.WMI.return_value
 
         expected = old_conn.Msvm_VirtualSystemManagementService()[0]
         self.assertEqual(expected, self.utils._vs_man_svc)
         self.assertIsNone(self.utils._vs_man_svc_attr)
-        mock_imp.load_source.assert_called_once_with(
+        imp.load_source.assert_called_once_with(
             'old_wmi', '%s.py' % fake_module_path)
 
     @mock.patch.object(baseutils.BaseUtilsVirt, '_get_wmi_compat_conn')