diff --git a/nova/tests/fixtures.py b/nova/tests/fixtures.py
index 2d85197fed40..32b91a8bc9f6 100644
--- a/nova/tests/fixtures.py
+++ b/nova/tests/fixtures.py
@@ -1067,6 +1067,15 @@ class PoisonFunctions(fixtures.Fixture):
     def setUp(self):
         super(PoisonFunctions, self).setUp()
 
+        try:
+            self._poison_libvirt_driver()
+        except ImportError:
+            # The libvirt driver uses modules that are not available
+            # on Windows.
+            if os.name != 'nt':
+                raise
+
+    def _poison_libvirt_driver(self):
         # The nova libvirt driver starts an event thread which only
         # causes trouble in tests. Make sure that if tests don't
         # properly patch it the test explodes.