[mutter/wip/carlosg/drop-no-clear-hint: 1/2] tests: Explicitly set a background color for offscreen actor tests

[Carlos Garnacho <carlosg src gnome org>]

commit e07530110e01413f2d2fa097d1bb373d8210ab36
Author: Carlos Garnacho <carlosg gnome org>
Date:   Fri Nov 1 14:52:41 2019 +0100

    tests: Explicitly set a background color for offscreen actor tests
    
    Those change opacity and read pixels, relying on an implicit stage color.
    We won't do that anymore.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/911

 src/tests/clutter/conform/actor-offscreen-redirect.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/src/tests/clutter/conform/actor-offscreen-redirect.c 
b/src/tests/clutter/conform/actor-offscreen-redirect.c
index 0a7c2a3c1..4970beb46 100644
--- a/src/tests/clutter/conform/actor-offscreen-redirect.c
+++ b/src/tests/clutter/conform/actor-offscreen-redirect.c
@@ -316,6 +316,9 @@ actor_offscreen_redirect (void)
 
   data.stage = clutter_test_get_stage ();
   data.parent_container = clutter_actor_new ();
+  clutter_actor_set_background_color (data.parent_container,
+                                      &(ClutterColor) { 255, 255, 255, 255 });
+
   data.container = g_object_new (foo_group_get_type (), NULL);
   data.foo_actor = g_object_new (foo_actor_get_type (), NULL);
   clutter_actor_set_size (CLUTTER_ACTOR (data.foo_actor), 100, 100);