Exceedingly minor tweak.
diff --git a/Lib/test/test_tempfile.py b/Lib/test/test_tempfile.py
index d5ae5de..e274c5b 100644
--- a/Lib/test/test_tempfile.py
+++ b/Lib/test/test_tempfile.py
@@ -307,7 +307,7 @@
         retval = os.spawnl(os.P_WAIT, sys.executable, decorated, tester, v, fd)
         self.failIf(retval < 0,
                     "child process caught fatal signal %d" % -retval)
-        self.failIf(retval > 0, "child process reports failure")
+        self.failIf(retval > 0, "child process reports failure %d"%retval)
 
     def test_textmode(self):
         # _mkstemp_inner can create files in text mode