[glib: 1/4] tests: Fix flaky socket-service test caused by GTask scheduling

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 2aea9c84c05b66355f9aaed6e4277e503fcba8a9
Author: Philip Withnall <withnall endlessm com>
Date:   Thu Feb 21 17:31:17 2019 +0000

    tests: Fix flaky socket-service test caused by GTask scheduling
    
    On about 1 in 3 test runs, the socket-service would fail with the
    ref_count assertion in connection_cb() failing (the ref_count would be 3
    rather than the expected 2).
    
    This was happening because the GTask from
    g_socket_listener_accept_socket_async() now always takes at least one
    main context iteration to return a result (whereas before
    6f3d57d2ee271017f37ebdceb1e15efa7ce0ac49 it might have taken zero), but
    the ref_count can drop below 3 before the process of returning a result
    starts. During the process of returning a result, the ref_count
    temporarily increases again, which is what was breaking the test.
    
    Fix this by waiting for one more main context iteration. This is a bit
    of a hack, but the real fix would be to expose the outstanding_accept
    boolean from GSocketService as public API (which the test can
    interrogate), and that seems too much like exposing internal state.
    
    Signed-off-by: Philip Withnall <withnall endlessm com>
    
    Helps: #1679

 gio/tests/socket-service.c | 5 +++++
 1 file changed, 5 insertions(+)
---
diff --git a/gio/tests/socket-service.c b/gio/tests/socket-service.c
index 5496b69c0..a5d114f29 100644
--- a/gio/tests/socket-service.c
+++ b/gio/tests/socket-service.c
@@ -222,6 +222,11 @@ test_threaded_712570 (void)
     g_main_context_iteration (NULL, TRUE);
   while (G_OBJECT (service)->ref_count > 3);
 
+  /* Wait some more iterations, as #GTask results are deferred to the next
+   * #GMainContext iteration, and propagation of a #GTask result takes an
+   * additional ref on the source object. */
+  g_main_context_iteration (NULL, FALSE);
+
   /* Drop our ref, then unlock the mutex and wait for the service to be
    * finalized. (Without the fix for 712570 it would hang forever here.)
    */