[glib] tests: Disable /date/month_names test with older libc versions

[Philip Withnall <pwithnall src gnome org>]

commit 493d3438e805c11f8f2f084e5b7b69f145a3bf38
Author: Philip Withnall <withnall endlessm com>
Date:   Tue Feb 20 12:02:20 2018 +0000

    tests: Disable /date/month_names test with older libc versions
    
    The test for %OB with g_date_strftime() fails with old libc versions
    which don’ŧ support the ‘O’ modifier. g_date_strftime() explicitly
    doesn’t add additional format placeholders over what’s supported by the
    system strftime(), so just disable the test in that case.
    
    The test remains useful on systems with newer libc versions, or on
    Windows, where the win32 fallback path is taken.
    
    Signed-off-by: Philip Withnall <withnall endlessm com>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=749206

 glib/tests/date.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)
---
diff --git a/glib/tests/date.c b/glib/tests/date.c
index 2ec33c5d8..4c2585281 100644
--- a/glib/tests/date.c
+++ b/glib/tests/date.c
@@ -176,12 +176,27 @@ test_parse (void)
 static void
 test_month_names (void)
 {
+#if defined(HAVE_LANGINFO_ABALTMON) || defined(G_OS_WIN32)
   GDate *gdate;
   gchar buf[101];
   gchar *oldlocale;
 #ifdef G_OS_WIN32
   LCID old_lcid;
 #endif
+#endif  /* defined(HAVE_LANGINFO_ABALTMON) || defined(G_OS_WIN32) */
+
+  g_test_bug ("749206");
+
+  /* This test can only work (on non-Windows platforms) if libc supports the %OB
+   * (etc.) format placeholders. If it doesn’t, strftime() (and hence
+   * g_date_strftime()) will return the placeholder unsubstituted.
+   * g_date_strftime() explicitly documents that it doesn’t provide any more
+   * format placeholders than the system strftime(), so we should skip the test
+   * in that case. If people need %OB support, they should depend on a suitable
+   * version of libc, or use g_date_time_format(). */
+#if !defined(HAVE_LANGINFO_ABALTMON) && !defined(G_OS_WIN32)
+  g_test_skip ("libc doesn’t support alternate month names");
+#else
 
 #define TEST_DATE(d,m,y,f,o)                                    \
   g_date_set_dmy (gdate, d, m, y);                              \
@@ -193,8 +208,6 @@ test_month_names (void)
   g_assert_cmpint (g_date_get_month (gdate), ==, m);            \
   g_assert_cmpint (g_date_get_year (gdate), ==, y);
 
-  g_test_bug ("749206");
-
   oldlocale = g_strdup (setlocale (LC_ALL, NULL));
 #ifdef G_OS_WIN32
   old_lcid = GetThreadLocale ();
@@ -373,7 +386,7 @@ test_month_names (void)
   SetThreadLocale (old_lcid);
 #endif
   g_free (oldlocale);
-
+#endif  /* defined(HAVE_LANGINFO_ABALTMON) || defined(G_OS_WIN32) */
 }
 
 static void