tests: Introduce generic device hot-plug/hot-unplug functions

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 for device deletion in an incorrect way, for example, we've got
to deal with both, error code and DEVICE_DEL event here). So let's provide
some proper generic functions for adding and removing a device instead.

The code for correctly unplugging a device has been taken from a patch
from Peter Xu.

Reviewed-by: Peter Xu <peterx@redhat.com>
Tested-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

1 files changed, 75 insertions, 0 deletions

diff --git a/tests/libqtest.c b/tests/libqtest.c
index b9a1f180e1..0c12b38906 100644
--- a/tests/libqtest.c
+++ b/tests/libqtest.c
@@ -987,3 +987,78 @@ 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_qmp_device_add(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);
+    g_assert(!qdict_haskey(response, "event")); /* We don't expect any events */
+    g_assert(!qdict_haskey(response, "error"));
+    QDECREF(response);
+}
+
+/*
+ * Generic hot-unplugging test via the device_del QMP command.
+ * Device deletion will get one response and one event. For example:
+ *
+ * {'execute': 'device_del','arguments': { 'id': 'scsi-hd'}}
+ *
+ * will get this one:
+ *
+ * {"timestamp": {"seconds": 1505289667, "microseconds": 569862},
+ *  "event": "DEVICE_DELETED", "data": {"device": "scsi-hd",
+ *  "path": "/machine/peripheral/scsi-hd"}}
+ *
+ * and this one:
+ *
+ * {"return": {}}
+ *
+ * But the order of arrival may vary - so we've got to detect both.
+ */
+void qtest_qmp_device_del(const char *id)
+{
+    QDict *response1, *response2, *event = NULL;
+    char *cmd;
+
+    cmd = g_strdup_printf("{'execute': 'device_del',"
+                          " 'arguments': { 'id': '%s' }}", id);
+    response1 = qmp(cmd);
+    g_free(cmd);
+    g_assert(response1);
+    g_assert(!qdict_haskey(response1, "error"));
+
+    response2 = qmp("");
+    g_assert(response2);
+    g_assert(!qdict_haskey(response2, "error"));
+
+    if (qdict_haskey(response1, "event")) {
+        event = response1;
+    } else if (qdict_haskey(response2, "event")) {
+        event = response2;
+    }
+    g_assert(event);
+    g_assert_cmpstr(qdict_get_str(event, "event"), ==, "DEVICE_DELETED");
+
+    QDECREF(response1);
+    QDECREF(response2);
+}