[PATCH v4 03/12] tests/qtest: Add qtest_has_accel() method

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

Introduce the qtest_has_accel() method which allows a runtime
query on whether a QEMU instance has an accelerator built-in.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
Since v2:
- reworded (Eric)
Since v1:
- rename qtest_probe_accel() -> qtest_has_accel()
- run with -machine none before creating QTestState
---
 tests/qtest/libqos/libqtest.h |  8 ++++++++
 tests/qtest/libqtest.c        | 29 +++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/tests/qtest/libqos/libqtest.h b/tests/qtest/libqos/libqtest.h
index a68dcd79d44..d80c618c18d 100644
--- a/tests/qtest/libqos/libqtest.h
+++ b/tests/qtest/libqos/libqtest.h
@@ -763,6 +763,14 @@ void qmp_expect_error_and_unref(QDict *rsp, const char *class);
  */
 bool qtest_probe_child(QTestState *s);
 
+/**
+ * qtest_has_accel:
+ * @accel_name: Accelerator name to check for.
+ *
+ * Returns: true if the accelerator is built in.
+ */
+bool qtest_has_accel(const char *accel_name);
+
 /**
  * qtest_set_expected_status:
  * @s: QTestState instance to operate on.
diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
index 71e359efcd3..2156b7e3972 100644
--- a/tests/qtest/libqtest.c
+++ b/tests/qtest/libqtest.c
@@ -393,6 +393,35 @@ QTestState *qtest_init_with_serial(const char *extra_args, int *sock_fd)
     return qts;
 }
 
+bool qtest_has_accel(const char *accel_name)
+{
+    bool has_accel = false;
+    QDict *response;
+    QList *accels;
+    QListEntry *accel;
+    QTestState *qts;
+
+    qts = qtest_initf("-accel qtest -machine none");
+    response = qtest_qmp(qts, "{'execute': 'query-accels'}");
+    accels = qdict_get_qlist(response, "return");
+
+    QLIST_FOREACH_ENTRY(accels, accel) {
+        QDict *accel_dict = qobject_to(QDict, qlist_entry_obj(accel));
+        const char *name = qdict_get_str(accel_dict, "name");
+
+        if (g_str_equal(name, accel_name)) {
+            has_accel = true;
+            break;
+        }
+    }
+    qobject_unref(response);
+
+    qtest_quit(qts);
+
+    return has_accel;
+}
+
+
 void qtest_quit(QTestState *s)
 {
     qtest_remove_abrt_handler(s);
-- 
2.26.3