[BUG] pytest hangs on fresh install

[dbwiddis]

What is the bug?

Following a complete uninstall and reinstall of many programs via homebrew, I reinstalled packages per the development guide.

Running poetry run pytest -v hangs at about 28% complete, with the log at this point:

tests/server/test_async_host.py::TestAsyncHost::test_init PASSED                                                                                       [ 28%]
tests/server/test_async_host.py::TestAsyncHost::test_run 
----------------------------------------------------------------------- live log call ------------------------------------------------------------------------
INFO     root:async_host.py:33 < server=<socket.socket fd=21, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=0, laddr=('127.0.0.1', 53500)>
INFO     root:test_async_host.py:56 > PASS
INFO     root:test_async_host.py:56 > QUIT
INFO     root:async_host.py:49 b'\x04PASS'

How can one reproduce the bug?

Start with a clean install on macOS and follow installation steps at https://github.com/opensearch-project/opensearch-sdk-py/blob/main/DEVELOPER_GUIDE.md#building-and-testing

What is the expected behavior?

Unit tests complete. Or the developer guide tells me I'm supposed to start something else up before running them.

What is your host/environment?

platform darwin -- Python 3.9.6, pytest-7.4.3, pluggy-1.3.0
Apple M2 Max
macOS Sonoma 14.2

Do you have any additional context?

When interrupting with Ctrl-C, I get

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! KeyboardInterrupt !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
/Users/danielwiddis/git/opensearch-sdk-py/src/opensearch_sdk_py/transport/stream_input.py:58: KeyboardInterrupt
(to show a full traceback on KeyboardInterrupt use --full-trace)
=============================================================== 39 passed in 299.74s (0:04:59) ===============================================================
Task exception was never retrieved
future: <Task finished name='Task-40' coro=<AsyncHost.on_connection() done, defined at /Users/danielwiddis/git/opensearch-sdk-py/src/opensearch_sdk_py/server/async_host.py:44> exception=KeyboardInterrupt()>

[dbwiddis]

Hang is in this line:

results = self.loop.run_until_complete(self.__both(["PASS", "QUIT"]))

Completes if I remove "PASS".

Loop in question:

def on_input(self, input: StreamInput) -> StreamOutput:
    while True:
        command = input.read_string()
        if command == "PASS":
            pass
        elif command == "EXCEPTION":
            self.terminating = True
            raise Exception(command)
        elif command == "QUIT":
            self.terminating = True
            response = StreamOutput()
            response.write_string("OK")
            return response

Tests pass if I put a return statement under the "PASS" conditional:

if command == "PASS":
    return

[dbwiddis]

Even with the "return" fix above it's flaky, sometimes hanging (apparently sending \x04PASS\x04QUIT in one message).

My hunch is some sort of I/O buffer where if PASS is not processed fast enough it doesn't catch QUIT, but that's purely guesswork.