Index: Lib/test/test_socket.py =================================================================== --- Lib/test/test_socket.py (revision 59319) +++ Lib/test/test_socket.py (working copy) @@ -199,6 +199,8 @@ def setUp(self): self.serv, self.cli = socket.socketpair() + self.assert_(isinstance(self.serv, socket.socket)) + self.assert_(isinstance(self.cli, socket.socket)) def tearDown(self): self.serv.close() @@ -561,6 +563,7 @@ return # On Windows, this doesn't exist fd = self.cli_conn.fileno() sock = socket.fromfd(fd, socket.AF_INET, socket.SOCK_STREAM) + self.assert_(isinstance(sock, socket.socket)) msg = sock.recv(1024) self.assertEqual(msg, MSG)