import socket
import threading

to_send = 1024 * 1024

def listen_and_receive():
    s = socket.socket()
    s.bind(('localhost', 27017))
    s.listen(1)
    conn, addr = s.accept()
    while True:
        data = conn.recv(1024)
        if not data:
            break
    conn.close()

t = threading.Thread(target=listen_and_receive)
t.start()

c = socket.socket()
c.connect(('localhost', 27017))
# sendall from cpython returns None or raises
sent = c.sendall("x" * to_send)
c.close()
t.join(10)
assert to_send == sent, "should have sent %d, only sent %d" % (to_send, sent)