tests/libqtest: Make qmp_assert_success() independent from global_qtest

The normal libqtest library functions should never depend on global_qtest.
Pass in the test state via parameter instead. And while we're at it,
also rename this function to qtest_qmp_assert_success() to make it clear
that it is part of libqtest.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190813093047.27948-7-thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

tests/libqtest.c

@@ -1111,13 +1111,13 @@ QDict *qmp(const char *fmt, ...)
     return response;
 }
 
-void qmp_assert_success(const char *fmt, ...)
+void qtest_qmp_assert_success(QTestState *qts, const char *fmt, ...)
 {
     va_list ap;
     QDict *response;
 
     va_start(ap, fmt);
-    response = qtest_vqmp(global_qtest, fmt, ap);
+    response = qtest_vqmp(qts, fmt, ap);
     va_end(ap);
 
     g_assert(response);

tests/libqtest.h

@@ -666,7 +666,8 @@ static inline void qtest_end(void)
 QDict *qmp(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
 
 /**
- * qmp_assert_success:
+ * qtest_qmp_assert_success:
+ * @qts: QTestState instance to operate on
  * @fmt...: QMP message to send to qemu, formatted like
  * qobject_from_jsonf_nofail().  See parse_escape() for what's
  * supported after '%'.
@@ -674,7 +675,8 @@ QDict *qmp(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
  * Sends a QMP message to QEMU and asserts that a 'return' key is present in
  * the response.
  */
-void qmp_assert_success(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
+void qtest_qmp_assert_success(QTestState *qts, const char *fmt, ...)
+    GCC_FMT_ATTR(2, 3);
 
 /*
  * qmp_eventwait:

tests/virtio-scsi-test.c

@@ -225,10 +225,12 @@ static void test_iothread_attach_node(void *obj, void *data,
     mkqcow2(tmp_path, 64);
 
     /* Attach the overlay to the null0 node */
-    qmp_assert_success("{'execute': 'blockdev-add', 'arguments': {"
-                       "   'driver': 'qcow2', 'node-name': 'overlay',"
-                       "   'backing': 'null0', 'file': {"
-                       "     'driver': 'file', 'filename': %s}}}", tmp_path);
+    qtest_qmp_assert_success(scsi_pci->pci_vdev.pdev->bus->qts,
+                             "{'execute': 'blockdev-add', 'arguments': {"
+                             "   'driver': 'qcow2', 'node-name': 'overlay',"
+                             "   'backing': 'null0', 'file': {"
+                             "     'driver': 'file', 'filename': %s}}}",
+                             tmp_path);
 
     /* Send a request to see if the AioContext is still right */
     ret = virtio_scsi_do_command(vs, write_cdb, NULL, 0, buf, 512, NULL);