[gtk+] Avoid a crash in testcalendar

[Matthias Clasen <matthiasc src gnome org>]

commit 7b9065c2eea5332ec69285ccdc52106a27e25111
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Dec 23 21:47:50 2014 -0500

    Avoid a crash in testcalendar
    
    When changing between months, we can get into a situation like
    'February 30", which GDate doesn't accept. Don't crash in that
    case.

 tests/testcalendar.c |   14 ++++++++++----
 1 files changed, 10 insertions(+), 4 deletions(-)
---
diff --git a/tests/testcalendar.c b/tests/testcalendar.c
index 4979011..16f04bf 100644
--- a/tests/testcalendar.c
+++ b/tests/testcalendar.c
@@ -67,10 +67,16 @@ calendar_date_to_string (CalendarData *data,
 
   gtk_calendar_get_date (GTK_CALENDAR(data->window),
                         &year, &month, &day);
-  date = g_date_new_dmy (day, month + 1, year);
-  g_date_strftime (buffer, buff_len-1, "%x", date);
-
-  g_date_free (date);
+  if (g_date_valid_dmy (day, month + 1, year))
+    {
+      date = g_date_new_dmy (day, month + 1, year);
+      g_date_strftime (buffer, buff_len-1, "%x", date);
+      g_date_free (date);
+    }
+  else
+    {
+      g_snprintf (buffer, buff_len - 1, "%d/%d/%d (invalid)", month + 1, day, year);
+    }
 }
 
 static void