[PATCH] tests: improve performance of device-introspect-test

["Daniel P. Berrangé" <berrange@redhat.com>]

Total execution time with "-m slow" and x86_64 QEMU, drops from 3
minutes 15 seconds, down to 54 seconds.

Individual tests drop from 17-20 seconds, down to 3-4 seconds.

The cost of this change is that any QOM bugs resulting in the test
failure will not be directly associated with the device that caused
the failure. The test case is not frequently identifying such bugs
though, and the cause is likely easily visible in the patch series
that causes the failure. So overall the shorter running time is
considered the more important factor.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 tests/qtest/device-introspect-test.c | 38 +++++++++++++---------------
 1 file changed, 18 insertions(+), 20 deletions(-)

diff --git a/tests/qtest/device-introspect-test.c b/tests/qtest/device-introspect-test.c
index 9abb5ec889..b4af1e19f6 100644
--- a/tests/qtest/device-introspect-test.c
+++ b/tests/qtest/device-introspect-test.c
@@ -105,14 +105,9 @@ static void test_one_device(QTestState *qts, const char *type)
 {
     QDict *resp;
     char *help;
-    char *qom_tree_start, *qom_tree_end;
-    char *qtree_start, *qtree_end;
 
     g_test_message("Testing device '%s'", type);
 
-    qom_tree_start = qtest_hmp(qts, "info qom-tree");
-    qtree_start = qtest_hmp(qts, "info qtree");
-
     resp = qtest_qmp(qts, "{'execute': 'device-list-properties',"
                           " 'arguments': {'typename': %s}}",
                type);
@@ -120,21 +115,6 @@ static void test_one_device(QTestState *qts, const char *type)
 
     help = qtest_hmp(qts, "device_add \"%s,help\"", type);
     g_free(help);
-
-    /*
-     * Some devices leave dangling pointers in QOM behind.
-     * "info qom-tree" or "info qtree" have a good chance at crashing then.
-     * Also make sure that the tree did not change.
-     */
-    qom_tree_end = qtest_hmp(qts, "info qom-tree");
-    g_assert_cmpstr(qom_tree_start, ==, qom_tree_end);
-    g_free(qom_tree_start);
-    g_free(qom_tree_end);
-
-    qtree_end = qtest_hmp(qts, "info qtree");
-    g_assert_cmpstr(qtree_start, ==, qtree_end);
-    g_free(qtree_start);
-    g_free(qtree_end);
 }
 
 static void test_device_intro_list(void)
@@ -232,10 +212,17 @@ static void test_device_intro_concrete(const void *args)
     QListEntry *entry;
     const char *type;
     QTestState *qts;
+    g_autofree char *qom_tree_start = NULL;
+    g_autofree char *qom_tree_end = NULL;
+    g_autofree char *qtree_start = NULL;
+    g_autofree char *qtree_end = NULL;
 
     qts = qtest_init(args);
     types = device_type_list(qts, false);
 
+    qom_tree_start = qtest_hmp(qts, "info qom-tree");
+    qtree_start = qtest_hmp(qts, "info qtree");
+
     QLIST_FOREACH_ENTRY(types, entry) {
         type = qdict_get_try_str(qobject_to(QDict, qlist_entry_obj(entry)),
                                  "name");
@@ -243,6 +230,17 @@ static void test_device_intro_concrete(const void *args)
         test_one_device(qts, type);
     }
 
+    /*
+     * Some devices leave dangling pointers in QOM behind.
+     * "info qom-tree" or "info qtree" have a good chance at crashing then.
+     * Also make sure that the tree did not change.
+     */
+    qom_tree_end = qtest_hmp(qts, "info qom-tree");
+    g_assert_cmpstr(qom_tree_start, ==, qom_tree_end);
+
+    qtree_end = qtest_hmp(qts, "info qtree");
+    g_assert_cmpstr(qtree_start, ==, qtree_end);
+
     qobject_unref(types);
     qtest_quit(qts);
     g_free((void *)args);
-- 
2.26.2