# test that socket.accept() on a non-blocking socket raises EAGAIN import socket s = socket.socket() s.bind(socket.getaddrinfo("127.0.0.1", 8123)[0][-1]) s.setblocking(False) s.listen(1) try: s.accept() except OSError as er: print(er.errno == 11) # 11 is EAGAIN s.close()