[glib] tests/mainloop: fix a race condition

[Dan Winship <danw src gnome org>]

commit baf0ebf7b233f05359f59dbee8d73fa15ef09407
Author: Dan Winship <danw gnome org>
Date:   Fri Apr 13 11:43:09 2012 -0400

    tests/mainloop: fix a race condition
    
    Rather than depending on the machine's speed/load, just interlock
    between the two threads properly.

 glib/tests/mainloop.c |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)
---
diff --git a/glib/tests/mainloop.c b/glib/tests/mainloop.c
index 614acc6..4d27985 100644
--- a/glib/tests/mainloop.c
+++ b/glib/tests/mainloop.c
@@ -253,6 +253,9 @@ call_func (gpointer data)
   return G_SOURCE_REMOVE;
 }
 
+static GMutex mutex;
+static GCond cond;
+
 static gpointer
 thread_func (gpointer data)
 {
@@ -261,6 +264,10 @@ thread_func (gpointer data)
 
   g_main_context_push_thread_default (ctx);
 
+  g_mutex_lock (&mutex);
+  g_cond_signal (&cond);
+  g_mutex_unlock (&mutex);
+
   source = g_timeout_source_new (500);
   g_source_set_callback (source, (GSourceFunc)g_thread_exit, NULL, NULL);
   g_source_attach (source, ctx);
@@ -293,9 +300,10 @@ test_invoke (void)
    * to another thread
    */
   ctx = g_main_context_new ();
+  g_mutex_lock (&mutex);
   thread = g_thread_new ("worker", thread_func, ctx);
 
-  g_usleep (1000); /* give some time to push the thread-default */
+  g_cond_wait (&cond, &mutex);
 
   g_main_context_invoke (ctx, func, thread);
   g_assert_cmpint (count, ==, 2);