--- a/src/protocols/tests/__init__.py
+++ b/src/protocols/tests/__init__.py
@@ -256,22 +256,6 @@
         makeSuite(GenerationTests,'check'),
     ]
 
-    try:
-        import zope.interface
-    except ImportError:
-        pass
-    else:
-        from protocols.tests import test_zope
-        tests.append( test_zope.test_suite() )
-
-    try:
-        from twisted.python.components import Interface
-    except (ImportError, SystemError):
-        pass
-    else:
-        from protocols.tests import test_twisted
-        tests.append( test_twisted.test_suite() )
-
     return TestSuite(
         tests
     )