Re: [PATCH 03/18] tests: support QTEST_TRACE env variable

[Thomas Huth <thuth@redhat.com>]

On 02/03/2022 18.49, Daniel P. Berrangé wrote:
> When debugging failing qtests it is useful to be able to turn on trace
> output to stderr. The QTEST_TRACE env variable contents get injected
> as a '-trace <str>' command line arg
> 
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>   tests/qtest/libqtest.c | 8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
> index 41f4da4e54..a85f8a6d05 100644
> --- a/tests/qtest/libqtest.c
> +++ b/tests/qtest/libqtest.c
> @@ -260,6 +260,9 @@ QTestState *qtest_init_without_qmp_handshake(const char *extra_args)
>       gchar *qmp_socket_path;
>       gchar *command;
>       const char *qemu_binary = qtest_qemu_binary();
> +    const char *trace = g_getenv("QTEST_TRACE");
> +    g_autofree char *tracearg = trace ?
> +        g_strdup_printf("-trace %s ", trace) : g_strdup("");
>   
>       s = g_new(QTestState, 1);
>   
> @@ -282,14 +285,15 @@ QTestState *qtest_init_without_qmp_handshake(const char *extra_args)
>   
>       qtest_add_abrt_handler(kill_qemu_hook_func, s);
>   
> -    command = g_strdup_printf("exec %s "
> +    command = g_strdup_printf("exec %s %s"
>                                 "-qtest unix:%s "
>                                 "-qtest-log %s "
>                                 "-chardev socket,path=%s,id=char0 "
>                                 "-mon chardev=char0,mode=control "
>                                 "-display none "
>                                 "%s"
> -                              " -accel qtest", qemu_binary, socket_path,
> +                              " -accel qtest",
> +                              qemu_binary, tracearg, socket_path,
>                                 getenv("QTEST_LOG") ? "/dev/fd/2" : "/dev/null",
>                                 qmp_socket_path,
>                                 extra_args ?: "");

Reviewed-by: Thomas Huth <thuth@redhat.com>