--- a/devtools/qunit.py	Mon Feb 20 15:16:55 2012 +0100
+++ b/devtools/qunit.py	Thu Feb 23 11:57:35 2012 +0100
@@ -64,7 +64,7 @@
 
     def __init__(self, url=None):
         self._process = None
-        self._tmp_dir = mkdtemp()
+        self._tmp_dir = mkdtemp(prefix='cwtest-ffxprof-')
         self._profile_data = {'uid': uuid4()}
         self._profile_name = self.profile_name_mask % self._profile_data
         fnull = open(os.devnull, 'w')