[glib/wip/antoniof/fallback-timezone-cache-lookup: 2/2] tests: Add a basic test for GTimeZone caching

[Philip Withnall <pwithnall src gnome org>]

commit ee9771a75f91cd96301e69cca7a94f95db1dec2b
Author: Philip Withnall <pwithnall endlessos org>
Date:   Thu Oct 15 10:52:31 2020 +0100

    tests: Add a basic test for GTimeZone caching
    
    This tests the previous few commits.
    
    Signed-off-by: Philip Withnall <pwithnall endlessos org>

 glib/tests/gdatetime.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
---
diff --git a/glib/tests/gdatetime.c b/glib/tests/gdatetime.c
index 3e75f4ed2..10ec9403b 100644
--- a/glib/tests/gdatetime.c
+++ b/glib/tests/gdatetime.c
@@ -2733,6 +2733,57 @@ test_time_zone_parse_rfc8536 (void)
     }
 }
 
+/* Check GTimeZone instances are cached. */
+static void
+test_time_zone_caching (void)
+{
+  GTimeZone *tz1 = NULL, *tz2 = NULL;
+
+  g_test_summary ("GTimeZone instances are cached");
+
+  /* Check a specific (arbitrary) timezone. These are only cached while third
+   * party code holds a ref to at least one instance. */
+#ifdef G_OS_UNIX
+  tz1 = g_time_zone_new ("Europe/London");
+  tz2 = g_time_zone_new ("Europe/London");
+  g_time_zone_unref (tz1);
+  g_time_zone_unref (tz2);
+#elif defined G_OS_WIN32
+  tz1 = g_time_zone_new ("GMT Standard Time");
+  tz2 = g_time_zone_new ("GMT Standard Time");
+  g_time_zone_unref (tz1);
+  g_time_zone_unref (tz2);
+#endif
+
+  /* Only compare pointers */
+  g_assert_true (tz1 == tz2);
+
+  /* Check the default timezone, local and UTC. These are cached internally in
+   * GLib, so should persist even after the last third party reference is
+   * dropped. */
+  tz1 = g_time_zone_new (NULL);
+  g_time_zone_unref (tz1);
+  tz2 = g_time_zone_new (NULL);
+  g_time_zone_unref (tz2);
+
+  g_assert_true (tz1 == tz2);
+
+  tz1 = g_time_zone_new_utc ();
+  g_time_zone_unref (tz1);
+  tz2 = g_time_zone_new_utc ();
+  g_time_zone_unref (tz2);
+
+  g_assert_true (tz1 == tz2);
+
+  tz1 = g_time_zone_new_local ();
+  g_time_zone_unref (tz1);
+  tz2 = g_time_zone_new_local ();
+  g_time_zone_unref (tz2);
+
+  g_assert_true (tz1 == tz2);
+}
+
+
 gint
 main (gint   argc,
       gchar *argv[])
@@ -2803,6 +2854,7 @@ main (gint   argc,
   g_test_add_func ("/GTimeZone/identifier", test_identifier);
   g_test_add_func ("/GTimeZone/new-offset", test_new_offset);
   g_test_add_func ("/GTimeZone/parse-rfc8536", test_time_zone_parse_rfc8536);
+  g_test_add_func ("/GTimeZone/caching", test_time_zone_caching);
 
   return g_test_run ();
 }