Jakub Kicinski wrote:
> More complex tests often have to spawn a background process,
> like a server which will respond to requests or tcpdump.
>
> Add support for creating such processes using the with keyword:
>
> with bkg("my-daemon", ..):
> # my-daemon is alive in this block
>
> My initial thought was to add this support to cmd() directly
> but it runs the command in the constructor, so by the time
> we __enter__ it's too late to make sure we used "background=True".
>
> Second useful helper transplanted from net_helper.sh is
> wait_port_listen().
>
> Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
> ---
> tools/testing/selftests/drivers/net/ping.py | 24 +++++++++++++--
> tools/testing/selftests/net/lib/py/utils.py | 33 +++++++++++++++++++++
> 2 files changed, 55 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/drivers/net/ping.py b/tools/testing/selftests/drivers/net/ping.py
> index 58aefd3e740f..8532e3be72ba 100755
> --- a/tools/testing/selftests/drivers/net/ping.py
> +++ b/tools/testing/selftests/drivers/net/ping.py
> @@ -1,9 +1,12 @@
> #!/usr/bin/env python3
> # SPDX-License-Identifier: GPL-2.0
>
> -from lib.py import ksft_run, ksft_exit, KsftXfailEx
> +import random
> +
> +from lib.py import ksft_run, ksft_exit
> +from lib.py import ksft_eq, KsftXfailEx
> from lib.py import NetDrvEpEnv
> -from lib.py import cmd
> +from lib.py import bkg, cmd, wait_port_listen
>
>
> def test_v4(cfg) -> None:
> @@ -22,6 +25,23 @@ from lib.py import cmd
> cmd(f"ping -c 1 -W0.5 {cfg.v6}", host=cfg.remote)
>
>
> +def test_tcp(cfg) -> None:
> + port = random.randrange(1024 + (1 << 15))
> + with bkg(f"nc -l {cfg.addr} {port}") as nc:
> + wait_port_listen(port)
> +
> + cmd(f"echo ping | nc {cfg.addr} {port}",
> + shell=True, host=cfg.remote)
> + ksft_eq(nc.stdout.strip(), "ping")
> +
> + port = random.randrange(1024 + (1 << 15))
> + with bkg(f"nc -l {cfg.remote_addr} {port}", host=cfg.remote) as nc:
> + wait_port_listen(port, host=cfg.remote)
> +
> + cmd(f"echo ping | nc {cfg.remote_addr} {port}", shell=True)
> + ksft_eq(nc.stdout.strip(), "ping")
> +
There are different netcat implementations floating around.
I notice that I have to pass -N on the client to terminate the
connection after EOF. Else both peers keep the connection open,
waiting for input. And explicitly pass -6 if passing an IPv6
address. I think this is the one that ships with Debian..
