Add a test for nonfatal assertions

Testing this in a normal testcaes is a bit tricky, since
triggering a non-fatal assertion has the side-effect of
marking the test as failed.

So just don't run any testcases here, but check the side-effect
manually. Since we don't produce TAP output when not using
g_test_run(), tell meson that we're using the exitcode protocol.

glib/tests/meson.build

@@ -159,6 +159,9 @@ glib_tests = {
     'extra_programs' : ['testing-helper'],
     'c_args' : cc.get_id() == 'gcc' ? ['-Werror=sign-conversion'] : [],
   },
+  'testing-nonfatal' : {
+    'protocol' : 'exitcode'
+  },
   'test-printf' : {},
   'thread' : {},
   'thread-deprecated' : {},

glib/tests/testing-nonfatal.c

@@ -0,0 +1,32 @@
+/* Copyright (C) 2024 Red Hat, Inc.
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <glib.h>
+
+int
+main (int argc, char *argv[])
+{
+  g_test_init (&argc, &argv, G_TEST_OPTION_NONFATAL_ASSERTIONS, NULL);
+
+  g_assert_cmpstr ("We can survive this!", ==, "Or maybe not?");
+
+  if (!g_test_failed ())
+    return 1;
+
+  return 0;
+}