diff --git a/src/zope/interface/common/tests/__init__.py b/src/zope/interface/common/tests/__init__.py
index b3bd5bea..20230729 100644
--- a/src/zope/interface/common/tests/__init__.py
+++ b/src/zope/interface/common/tests/__init__.py
@@ -60,7 +60,8 @@ def test(self, stdlib_class=stdlib_class, iface=iface):
 
                 self.assertTrue(self.verify(iface, stdlib_class))
 
-            suffix = "%s_%s_%s" % (
+            suffix = "%s_%s_%s_%s" % (
+                stdlib_class.__module__.replace('.', '_'),
                 stdlib_class.__name__,
                 iface.__module__.replace('.', '_'),
                 iface.__name__