When running certain HMP commands (like "device_del") via QMP, we
can sometimes get a QMP event in the response first, so that the
"g_assert(ret)" statement in qtest_hmp() triggers and the test
fails. So ignore such QMP events when looking for the real
return value from QMP.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 tests/libqtest.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tests/libqtest.c b/tests/libqtest.c
index a5c3d2b..c9b2d76 100644
--- a/tests/libqtest.c
+++ b/tests/libqtest.c
@@ -580,6 +580,12 @@ char *qtest_hmpv(QTestState *s, const char *fmt, va_list ap)
                      " 'arguments': {'command-line': %s}}",
                      cmd);
     ret = g_strdup(qdict_get_try_str(resp, "return"));
+    while (ret == NULL && qdict_get_try_str(resp, "event")) {
+        /* Ignore asynchronous QMP events */
+        QDECREF(resp);
+        resp = qtest_qmp_receive(s);
+        ret = g_strdup(qdict_get_try_str(resp, "return"));
+    }
     g_assert(ret);
     QDECREF(resp);
     g_free(cmd);
-- 
1.8.3.1

On Tue, Mar 21, 2017 at 11:39:50AM +0100, Thomas Huth wrote:
> When running certain HMP commands (like "device_del") via QMP, we
> can sometimes get a QMP event in the response first, so that the
> "g_assert(ret)" statement in qtest_hmp() triggers and the test
> fails. So ignore such QMP events when looking for the real
> return value from QMP.
> 
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  tests/libqtest.c | 6 ++++++
>  1 file changed, 6 insertions(+)

qmp.py keeps a queue of events so they can be processed later.  I guess
an event queue will be needed eventually because discarding events makes
it hard to write reliable test cases that check for events.

But as long as current qtests work correctly:

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

On 23.03.2017 09:52, Stefan Hajnoczi wrote:
> On Tue, Mar 21, 2017 at 11:39:50AM +0100, Thomas Huth wrote:
>> When running certain HMP commands (like "device_del") via QMP, we
>> can sometimes get a QMP event in the response first, so that the
>> "g_assert(ret)" statement in qtest_hmp() triggers and the test
>> fails. So ignore such QMP events when looking for the real
>> return value from QMP.
>>
>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>> ---
>>  tests/libqtest.c | 6 ++++++
>>  1 file changed, 6 insertions(+)
> 
> qmp.py keeps a queue of events so they can be processed later.  I guess
> an event queue will be needed eventually because discarding events makes
> it hard to write reliable test cases that check for events.

Yes, but in that case the test likely should not use the hmp() functions
at all and use qmp directly.

> But as long as current qtests work correctly:
> 
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

Thanks!

 Thomas