[gtk+] gtkicontheme: Don’t emit warning about fallback theme when in unit tests

[Matthias Clasen <matthiasc src gnome org>]

commit 76721e736e9605b3a7ec76d3676d8cb5f4172490
Author: Philip Withnall <philip withnall collabora co uk>
Date:   Wed Aug 3 21:12:27 2016 +0100

    gtkicontheme: Don’t emit warning about fallback theme when in unit tests
    
    In order to eliminate g_test_expect_message() (which doesn’t work with
    G_LOG_USE_STRUCTURED), make the warning about the fallback theme not
    existing be conditional on the icon theme search path containing a
    system path. Any application code which modifies the search path does so
    through appends and prepends, so this should not affect whether the
    warning is emitted in production.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=769485

 testsuite/gtk/icontheme.c |   31 ++++++++++++++++++++++---------
 1 files changed, 22 insertions(+), 9 deletions(-)
---
diff --git a/testsuite/gtk/icontheme.c b/testsuite/gtk/icontheme.c
index a70f75b..cf46647 100644
--- a/testsuite/gtk/icontheme.c
+++ b/testsuite/gtk/icontheme.c
@@ -201,15 +201,6 @@ test_basics (void)
 {
   /* just a basic boring lookup so we know everything works */
   assert_icon_lookup ("simple", 16, 0, "/icons/16x16/simple.png");
-
-  /* The first time an icon is looked up that doesn't exist, GTK spews a 
-   * warning.
-   * We make that happen right here, so we can get rid of the warning 
-   * and do failing lookups in other tests.
-   */
-  g_test_expect_message ("Gtk", G_LOG_LEVEL_WARNING, "Could not find the icon*");
-  assert_icon_lookup_fails ("this-icon-totally-does-not-exist", 16, 0);
-  g_test_assert_expected_messages ();
 }
 
 static void
@@ -771,11 +762,33 @@ test_nonsquare_symbolic (void)
   g_object_unref (info);
 }
 
+static GLogWriterOutput
+log_writer_drop_warnings (GLogLevelFlags   log_level,
+                          const GLogField *fields,
+                          gsize            n_fields,
+                          gpointer         user_data)
+{
+  gboolean *ignore_warnings = user_data;
+
+  if (log_level == G_LOG_LEVEL_WARNING && *ignore_warnings)
+    return G_LOG_WRITER_HANDLED;
+
+  return g_log_writer_default (log_level, fields, n_fields, user_data);
+}
+
 int
 main (int argc, char *argv[])
 {
+  gboolean ignore_warnings = TRUE;
+
   gtk_test_init (&argc, &argv);
 
+  /* Ignore the one-time warning that the fallback icon theme can’t be found
+   * (because we’ve changed the search paths). */
+  g_log_set_writer_func (log_writer_drop_warnings, &ignore_warnings, NULL);
+  assert_icon_lookup_fails ("this-icon-totally-does-not-exist", 16, 0);
+  ignore_warnings = FALSE;
+
   g_test_add_func ("/icontheme/basics", test_basics);
   g_test_add_func ("/icontheme/lookup-order", test_lookup_order);
   g_test_add_func ("/icontheme/generic-fallback", test_generic_fallback);