open_connection() doesn't fail

[skyguy]

There seems to be a difference in behaviour between MicroPython (v.1.21) and CPython when using the asyncio.open_connection() function. If the destination port is not open and sends a TCP reset, CPython gives an exception in open_connection() , while MicroPython only gives an exception once you try to read() from the stream.

Is this just a timing optimisation where MicroPython doesn't wait around for the TCP reset?

Sample code:

import asyncio

async def conn_fail_test():
    reader, writer = await asyncio.open_connection('192.168.8.1', 99)
    # CPython fails here
    await reader.read(1)
    # MicroPython fails here

asyncio.run(conn_fail_test())