[glib: 1/2] tests: Explicitly set TZ=UTC for g_time_val_from_iso8601() testing

[Emmanuele Bassi <ebassi src gnome org>]

commit b1bfebc61cc705f1191b126faf30710b91a54e22
Author: Philip Withnall <withnall endlessm com>
Date:   Sat Aug 11 21:59:17 2018 +0100

    tests: Explicitly set TZ=UTC for g_time_val_from_iso8601() testing
    
    Some of the test vectors don’t specify a timezone, so the local one is
    used; the comparisons to the expected results (which are in UTC) then
    fail.
    
    See discussion in
    https://gitlab.gnome.org/GNOME/glib/merge_requests/225.
    
    Signed-off-by: Philip Withnall <withnall endlessm com>

 glib/tests/timer.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)
---
diff --git a/glib/tests/timer.c b/glib/tests/timer.c
index c0b9ba802..5ee191dd9 100644
--- a/glib/tests/timer.c
+++ b/glib/tests/timer.c
@@ -134,6 +134,7 @@ typedef struct {
 static void
 test_timeval_from_iso8601 (void)
 {
+  gchar *old_tz = g_strdup (g_getenv ("TZ"));
   TimeValParseTest tests[] = {
     { TRUE, "1990-11-01T10:21:17Z", { 657454877, 0 } },
     { TRUE, "19901101T102117Z", { 657454877, 0 } },
@@ -190,7 +191,12 @@ test_timeval_from_iso8601 (void)
   gboolean success;
   gint i;
 
-  g_unsetenv ("TZ");
+  /* Always run in UTC so the comparisons of parsed values are valid. */
+  if (!g_setenv ("TZ", "UTC", TRUE))
+    {
+      g_test_skip ("Failed to set TZ=UTC");
+      return;
+    }
 
   for (i = 0; i < G_N_ELEMENTS (tests); i++)
     {
@@ -204,6 +210,13 @@ test_timeval_from_iso8601 (void)
           g_assert_cmpint (out.tv_usec, ==, tests[i].val.tv_usec);
         }
     }
+
+  if (old_tz != NULL)
+    g_assert_true (g_setenv ("TZ", old_tz, TRUE));
+  else
+    g_unsetenv ("TZ");
+
+  g_free (old_tz);
 }
 
 typedef struct {