Typo on side_effect rendering the test useless

side_effect does not take a trailing "s", calling
side_effects will simply ignore the call and
continue.  These test work because the no return
value are set, therefore the result is false.

Without changing the tests you can comment out
the try/except without breaking anything.

Fixing the tests shows that the call to
netifaces.ifaddresses was not covered for OSError
and test was missing for ValueError

Change-Id: I770390e99b4b614aff5512da11c0c226dc38b85f

neutron/agent/windows/ip_lib.py

@@ -50,14 +50,15 @@ class IPDevice(object):
     def device_has_ip(self, ip):
         try:
             device_addresses = netifaces.ifaddresses(self.device_name)
-        except ValueError:  # The device does not exist on the system
+        except ValueError:
+            LOG.error(_LE("The device does not exist on the system: %s."),
+                      self.device_name)
             return False
-
-        try:
-            addresses = [ip_addr['addr'] for ip_addr in
-                         device_addresses.get(netifaces.AF_INET, [])]
-            return ip in addresses
         except OSError:
             LOG.error(_LE("Failed to get ip addresses for interface: %s."),
                       self.device_name)
             return False
+
+        addresses = [ip_addr['addr'] for ip_addr in
+                     device_addresses.get(netifaces.AF_INET, [])]
+        return ip in addresses

neutron/tests/unit/agent/windows/test_ip_lib.py

@@ -48,7 +48,7 @@ class TestIpWrapper(base.BaseTestCase):
 
     @mock.patch('netifaces.interfaces')
     def test_get_devices_error(self, mock_interfaces):
-        mock_interfaces.side_effects = OSError
+        mock_interfaces.side_effect = OSError
         ret = ip_lib.IPWrapper().get_devices()
 
         self.assertEqual([], ret)
@@ -77,7 +77,16 @@ class TestIpDevice(base.BaseTestCase):
 
     @mock.patch('netifaces.ifaddresses')
     def test_device_has_ip_error(self, mock_netifaces):
-        mock_netifaces.side_effects = OSError
+        mock_netifaces.side_effect = OSError
+
+        ret = ip_lib.IPDevice("fake_dev").device_has_ip(
+            mock.sentinel.fake_addr)
+
+        self.assertFalse(ret)
+
+    @mock.patch('netifaces.ifaddresses')
+    def test_device_not_found(self, mock_netifaces):
+        mock_netifaces.side_effect = ValueError
 
         ret = ip_lib.IPDevice("fake_dev").device_has_ip(
             mock.sentinel.fake_addr)