Re: [PULL 04/35] tests/unit: drop hacky race avoidance in test-io-channel-command

[Philippe Mathieu-Daudé]

Hi Alex, Thomas.

On 26/1/23 12:22, Alex Bennée wrote:
> We don't need to play timing games to ensure one socat wins over the
> other, just create the fifo they both can use before spawning the
> processes. However in the process we need to disable two tests for
> Windows platforms as we don't have an abstraction for mkfifo().
>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1403
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> Message-Id: <20230124180127.1881110-5-alex.bennee@linaro.org>
>
> diff --git a/tests/unit/test-io-channel-command.c 
> b/tests/unit/test-io-channel-command.c
> index 19f72eab96..425e2f5594 100644
> --- a/tests/unit/test-io-channel-command.c
> +++ b/tests/unit/test-io-channel-command.c
> @@ -20,6 +20,8 @@
>   
>   #include "qemu/osdep.h"
>   #include <glib/gstdio.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
>   #include "io/channel-command.h"
>   #include "io-channel-helpers.h"
>   #include "qapi/error.h"
> @@ -29,6 +31,7 @@
>   
>   static char *socat = NULL;
>   
> +#ifndef _WIN32
>   static void test_io_channel_command_fifo(bool async)
>   {
>       g_autofree gchar *tmpdir = g_dir_make_tmp("qemu-test-io-channel.XXXXXX", 
> NULL);
> @@ -40,12 +43,13 @@ static void test_io_channel_command_fifo(bool async)
>       QIOChannel *src, *dst;
>       QIOChannelTest *test;
>   
> +    if (mkfifo(fifo, 0600)) {
> +        g_error("mkfifo: %s", strerror(errno));
> +    }
> +
>       src = QIO_CHANNEL(qio_channel_command_new_spawn((const char **) srcargv,
>                                                       O_WRONLY,
>                                                       &error_abort));
> -    /* try to avoid a race to create the socket */
> -    g_usleep(1000);
> -
>       dst = QIO_CHANNEL(qio_channel_command_new_spawn((const char **) dstargv,
>                                                       O_RDONLY,
>                                                       &error_abort));
> @@ -60,7 +64,6 @@ static void test_io_channel_command_fifo(bool async)

Testing on Darwin/Aarch64 I'm getting (reproducible):

78/93 qemu:unit / test-io-channel-command             ERROR 
2.38s   killed by signal 13 SIGPIPE
>>> MALLOC_PERTURB_=10 G_TEST_BUILDDIR=./tests/unit 
G_TEST_SRCDIR=tests/unit ./tests/unit/test-io-channel-command --tap -k
―――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――
stderr:
2023/02/03 08:26:49 socat[32507] E 
mkfifo(/var/folders/yj/r7khncsj4d77k04ybz9lw4tm0000gn/T/qemu-test-io-channel.GMARZ1/test-io-channel-command.fifo, 
438): File exists

(test program exited with status code -13)

TAP parsing error: Too few tests run (expected 4, got 0)
―――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――

We call g_rmdir(), but I see various qtests calling unlink()
before rmdir(). Do we need it here?

+       g_unlink(fifo);

>       g_rmdir(tmpdir);
>   }
>   
> -
>   static void test_io_channel_command_fifo_async(void)
>   {
>       if (!socat) {
> @@ -80,6 +83,7 @@ static void test_io_channel_command_fifo_sync(void)
>   
>       test_io_channel_command_fifo(false);
>   }
> +#endif
>   
>   
>   static void test_io_channel_command_echo(bool async)
> @@ -124,10 +128,12 @@ int main(int argc, char **argv)
>   
>       socat = g_find_program_in_path("socat");
>   
> +#ifndef _WIN32
>       g_test_add_func("/io/channel/command/fifo/sync",
>                       test_io_channel_command_fifo_sync);
>       g_test_add_func("/io/channel/command/fifo/async",
>                       test_io_channel_command_fifo_async);
> +#endif
>       g_test_add_func("/io/channel/command/echo/sync",
>                       test_io_channel_command_echo_sync);
>       g_test_add_func("/io/channel/command/echo/async",