Index: run_tests.py
===================================================================
--- run_tests.py	(revision 539)
+++ run_tests.py	(revision 540)
@@ -447,6 +447,9 @@
     This could theoreticaly result in an infinite loop, if you create symlink
     cycles in your Zope sandbox, so don't do that.
     """
+    from os.path import basename, normpath
+    if basename(normpath(top)) in ('.svn', '.hq', 'CVS'):
+        return
     try:
         names = os.listdir(top)
     except os.error: