year2038: Add tests.

* tests/test-year2038.c: New file.
* modules/year2038-tests: New file.

1 files changed, 39 insertions, 0 deletions

diff --git a/tests/test-year2038.c b/tests/test-year2038.c
new file mode 100644
index 0000000000..58c1058b13
--- /dev/null
+++ b/tests/test-year2038.c
@@ -0,0 +1,39 @@
+/* Test of year2038 module.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2023.  */
+
+/* This test fails if AC_SYS_YEAR2038 could not arrange for a time_t
+   that supports values > 2147483647.
+   This can happen
+     - on systems that are not year 2038 safe, or
+     - if the user specified --disable-year2038 at configure time.
+   It is intended that this test fails in these circumstances.  */
+
+#include <config.h>
+
+#include <sys/types.h>
+
+int
+main (void)
+{
+  /* Check the size and sign of time_t.  */
+  if (sizeof (time_t) <= 4 && (time_t)-1 < 0)
+    /* time_t is only 32 bits wide and signed.  */
+    return 1;
+
+  return 0;
+}