micropython/tests/net_hosted/accept_nonblock.py

# test that socket.accept() on a non-blocking socket raises EAGAIN

try:
    import usocket as socket
except:
    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()