I left a few minor comments in the code review. I agree automated testing would be awkward for Readline. It should be possible using a pseudoterminal (pty). In fact there is already very basic testing that does this in /Lib/test/test_builtin.py, class PtyTests. It only tests the input() prompt. I could have a go at writing a test. I guess pseudocode for a test would look a bit like: def run_pty(script): [master, slave] = pty.openpty() with subprocess.Popen(script, stdin=slave, stdout=slave, stderr=slave) # Read and write concurrently like proc.communicate() master.write(b"dummy input\r") return slave.read() template = """\ import readline readline.set_auto_history({}) input() print("History length:", readline.get_current_history_length()) """ def test_auto_history_enabled(self): output = run_session(template.format(True)) self.assertIn(b"History length: 1\n", output) def test_auto_history_disabled(self): output = run_session(template.format(False)) self.assertIn(b"History length: 0\n", output)