Issue #20555: Use specific asserts in urllib, httplib, ftplib, cgi, wsgiref tests.
diff --git a/Lib/test/test_wsgiref.py b/Lib/test/test_wsgiref.py
index 88d4a3d..401d784 100644
--- a/Lib/test/test_wsgiref.py
+++ b/Lib/test/test_wsgiref.py
@@ -155,7 +155,7 @@
         # Check existing value
         env = {key:alt}
         util.setup_testing_defaults(env)
-        self.assertTrue(env[key] is alt)
+        self.assertIs(env[key], alt)
 
     def checkCrossDefault(self,key,value,**kw):
         util.setup_testing_defaults(kw)
@@ -302,7 +302,7 @@
         self.assertEqual(Headers(test[:]).keys(), ['x'])
         self.assertEqual(Headers(test[:]).values(), ['y'])
         self.assertEqual(Headers(test[:]).items(), test)
-        self.assertFalse(Headers(test).items() is test)  # must be copy!
+        self.assertIsNot(Headers(test).items(), test)  # must be copy!
 
         h=Headers([])
         del h['foo']   # should not raise an error