diff --git a/Lib/test/test_wsgiref.py b/Lib/test/test_wsgiref.py
index 06591ad..1f46a3e 100755
--- a/Lib/test/test_wsgiref.py
+++ b/Lib/test/test_wsgiref.py
@@ -523,7 +523,8 @@
             "Content-Length: %d\r\n"
             "\r\n%s" % (h.error_status,len(h.error_body),h.error_body))
 
-        self.failUnless(h.stderr.getvalue().find("AssertionError")<>-1)
+        self.assertTrue("AssertionError" in h.stderr.getvalue(),
+                        "AssertionError not in stderr")
 
     def testErrorAfterOutput(self):
         MSG = "Some output has been sent"
@@ -536,7 +537,8 @@
         self.assertEqual(h.stdout.getvalue(),
             "Status: 200 OK\r\n"
             "\r\n"+MSG)
-        self.failUnless(h.stderr.getvalue().find("AssertionError")<>-1)
+        self.assertTrue("AssertionError" in h.stderr.getvalue(),
+                        "AssertionError not in stderr")
 
 
     def testHeaderFormats(self):