Add a test for window focus handling

This is a small test that checks that gtk_window_set/get_focus
behave as expected, regardless of the window being shown or hidden.

testsuite/gtk/Makefile.am

@@ -42,6 +42,7 @@ TEST_PROGS += 			\
 	expander		\
 	firefox-stylecontext	\
 	floating		\
+	focus			\
 	gestures		\
 	grid			\
 	gtkmenu			\

testsuite/gtk/focus.c

@@ -0,0 +1,56 @@
+#include <gtk/gtk.h>
+
+static void
+test_window_focus (void)
+{
+  GtkWidget *window;
+  GtkWidget *box;
+  GtkWidget *entry1;
+  GtkWidget *entry2;
+
+  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+  box = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 0);
+  gtk_container_add (GTK_CONTAINER (window), box);
+  gtk_container_add (GTK_CONTAINER (box), gtk_label_new ("label1"));
+  entry1 = gtk_entry_new ();
+  gtk_container_add (GTK_CONTAINER (box), entry1);
+  gtk_container_add (GTK_CONTAINER (box), gtk_label_new ("label2"));
+  entry2 = gtk_entry_new ();
+  gtk_container_add (GTK_CONTAINER (box), entry2);
+
+  gtk_widget_show_all (box);
+
+  g_assert_null (gtk_window_get_focus (GTK_WINDOW (window)));
+
+  gtk_window_set_focus (GTK_WINDOW (window), entry1);
+
+  g_assert (gtk_window_get_focus (GTK_WINDOW (window)) == entry1);
+
+  gtk_widget_show_now (window);
+
+  g_assert (gtk_window_get_focus (GTK_WINDOW (window)) == entry1);
+
+  gtk_widget_grab_focus (entry2);
+
+  g_assert (gtk_window_get_focus (GTK_WINDOW (window)) == entry2);
+
+  gtk_widget_hide (window);
+
+  g_assert (gtk_window_get_focus (GTK_WINDOW (window)) == entry2);
+
+  gtk_window_set_focus (GTK_WINDOW (window), entry1);
+
+  g_assert (gtk_window_get_focus (GTK_WINDOW (window)) == entry1);
+
+  gtk_widget_destroy (window);
+}
+
+int
+main (int argc, char *argv[])
+{
+  gtk_test_init (&argc, &argv);
+
+  g_test_add_func ("/focus/window", test_window_focus);
+
+  return g_test_run ();
+}