[gtk/label-underline-markup] Add a mnemonic testcase

[Matthias Clasen <matthiasc src gnome org>]

commit 89f57d4ff6e500d42f79d05ab4d691e540bc1eee
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Jun 15 13:32:31 2021 -0400

    Add a mnemonic testcase
    
    Add a testcase that tests the label mnemonic handling
    that was fixed in the previous commit.

 testsuite/gtk/label.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
---
diff --git a/testsuite/gtk/label.c b/testsuite/gtk/label.c
index c075e15139..3b1531a36b 100644
--- a/testsuite/gtk/label.c
+++ b/testsuite/gtk/label.c
@@ -196,12 +196,35 @@ test_label_markup (void)
   gtk_window_destroy (GTK_WINDOW (window));
 }
 
+static void
+test_label_underline (void)
+{
+  GtkWidget *window;
+  GtkWidget *label;
+
+  window = gtk_window_new ();
+
+  label = gtk_label_new ("");
+
+  gtk_window_set_child (GTK_WINDOW (window), label);
+  gtk_window_set_mnemonics_visible (GTK_WINDOW (window), TRUE);
+
+  gtk_label_set_use_markup (GTK_LABEL (label), FALSE);
+  gtk_label_set_use_underline (GTK_LABEL (label), TRUE);
+  gtk_label_set_label (GTK_LABEL (label), "tes_t & no markup <<");
+
+  g_assert_cmpint (gtk_label_get_mnemonic_keyval (GTK_LABEL (label)), ==, GDK_KEY_t);
+
+  gtk_window_destroy (GTK_WINDOW (window));
+}
+
 int
 main (int argc, char *argv[])
 {
   gtk_test_init (&argc, &argv);
 
   g_test_add_func ("/label/markup-parse", test_label_markup);
+  g_test_add_func ("/label/underline-parse", test_label_underline);
 
   return g_test_run ();
 }