Re: [Qemu-devel] [PATCH 4/6] tests: Introduce generic device hot-plug/hot-unplug functions

[Cornelia Huck <cohuck@redhat.com>]

On Thu, 17 Aug 2017 08:25:11 +0200
Thomas Huth <thuth@redhat.com> wrote:

> A lot of tests provide code for adding and removing a device via the
> device_add and device_del QMP commands. Maintaining this code in so
> many places is cumbersome and error-prone (some of the code parts
> check the responses in an incorrect way, for example), so let's
> provide some proper generic qtest functions for adding and removing a
> device instead.

This sounds like a good idea.

> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  tests/libqos/pci.c         | 19 ++-------------
>  tests/libqos/usb.c         | 30 +++++------------------
>  tests/libqtest.c           | 60 ++++++++++++++++++++++++++++++++++++++++++++++
>  tests/libqtest.h           | 19 +++++++++++++++
>  tests/usb-hcd-uhci-test.c  | 26 ++------------------
>  tests/usb-hcd-xhci-test.c  | 51 ++++-----------------------------------
>  tests/virtio-scsi-test.c   | 24 ++-----------------
>  tests/virtio-serial-test.c | 25 +++----------------
>  8 files changed, 98 insertions(+), 156 deletions(-)
> 

> diff --git a/tests/libqtest.c b/tests/libqtest.c
> index b9a1f18..4339d97 100644
> --- a/tests/libqtest.c
> +++ b/tests/libqtest.c
> @@ -987,3 +987,63 @@ void qtest_cb_for_every_machine(void (*cb)(const char *machine))
>      qtest_end();
>      QDECREF(response);
>  }
> +
> +/**
> + * Generic hot-plugging test via the device_add QMP command
> + */
> +void qtest_hot_plug_device(const char *driver, const char *id,
> +                           const char *fmt, ...)
> +{
> +    QDict *response;
> +    char *cmd, *opts = NULL;
> +    va_list va;
> +
> +    if (fmt) {
> +        va_start(va, fmt);
> +        opts = g_strdup_vprintf(fmt, va);
> +        va_end(va);
> +    }
> +
> +    cmd = g_strdup_printf("{'execute': 'device_add',"
> +                          " 'arguments': { 'driver': '%s', 'id': '%s'%s%s }}",
> +                          driver, id, opts ? ", " : "", opts ? opts : "");
> +    g_free(opts);
> +
> +    response = qmp(cmd);
> +    g_free(cmd);
> +    g_assert(response);
> +    while (qdict_haskey(response, "event")) {
> +        /* We can get DEVICE_DELETED events in case something went wrong */
> +        g_assert_cmpstr(qdict_get_str(response, "event"), !=, "DEVICE_DELETED");

Is there other stuff we should check for?

> +        QDECREF(response);
> +        response = qmp("");
> +        g_assert(response);
> +    }
> +    g_assert(!qdict_haskey(response, "error"));
> +    QDECREF(response);
> +}
> +
> +/**
> + * Generic hot-unplugging test via the device_del QMP command
> + */
> +void qtest_hot_unplug_device(const char *id)
> +{
> +    QDict *response;
> +    char *cmd;
> +
> +    cmd = g_strdup_printf("{'execute': 'device_del',"
> +                          " 'arguments': { 'id': '%s' }}", id);
> +
> +    response = qmp(cmd);
> +    g_free(cmd);
> +    g_assert(response);
> +    while (qdict_haskey(response, "event")) {
> +        /* We should get DEVICE_DELETED event first */
> +        g_assert_cmpstr(qdict_get_str(response, "event"), ==, "DEVICE_DELETED");

'should' does not sound assert-worthy to me :) Is this an expected event?

> +        QDECREF(response);
> +        response = qmp("");
> +        g_assert(response);
> +    }
> +    g_assert(!qdict_haskey(response, "error"));
> +    QDECREF(response);
> +}