diff --git a/test/TestCmd.py b/test/TestCmd.py
index d3b13e29cc..abc56102c6 100644
--- a/test/TestCmd.py
+++ b/test/TestCmd.py
@@ -533,8 +533,8 @@ def workdir_set(self, path):
         else:
             if path != None:
                 if path == '':
-                    path = tempfile.mktemp()
-                if path != None:
+                    path = tempfile.mkdtemp(prefix="b2")
+                elif path != None:
                     os.mkdir(path)
                 self._dirlist.append(path)
                 global _Cleanup