tests: Clean up string interpolation around qtest_qmp_device_add()

Leaving interpolation into JSON to qmp() is more robust than building
QMP input manually, as explained in the commit before previous.

qtest_qmp_device_add() and its wrappers interpolate into JSON as
follows:

* qtest_qmp_device_add() interpolates members into a JSON object.

* So do its wrappers qpci_plug_device_test() and usb_test_hotplug().

* usb_test_hotplug() additionally interpolates strings and numbers
  into JSON strings.

Clean them up:

* Have qtest_qmp_device_add() take its extra device properties as
  arguments for qdict_from_jsonf_nofail() instead of a string
  containing JSON members.

* Drop qpci_plug_device_test(), use qtest_qmp_device_add()
  directly.

* Change usb_test_hotplug() parameter @port to string, to avoid
  interpolation.  Interpolate @hcd_id separately.

Bonus: gets rid of a non-literal format string.  A step towards
compile-time format string checking without triggering
-Wformat-nonliteral.

Cc: Thomas Huth <thuth@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180806065344.7103-15-armbru@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/tests/virtio-serial-test.c b/tests/virtio-serial-test.c
index 7cc7060264..e4b18b1c8a 100644
--- a/tests/virtio-serial-test.c
+++ b/tests/virtio-serial-test.c
@@ -18,7 +18,7 @@ static void virtio_serial_nop(void)
 
 static void hotplug(void)
 {
-    qtest_qmp_device_add("virtserialport", "hp-port", NULL);
+    qtest_qmp_device_add("virtserialport", "hp-port", "{}");
 
     qtest_qmp_device_del("hp-port");
 }