1 files changed, 95 insertions, 0 deletions
diff --git a/time/tst-timegm.c b/time/tst-timegm.c
new file mode 100644
index 0000000000..d9b08d380c
--- /dev/null
+++ b/time/tst-timegm.c
@@ -0,0 +1,95 @@
+/* Basic tests for timegm.
+   Copyright (C) 2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <time.h>
+#include <stdlib.h>
+#include <support/check.h>
+
+static void
+do_test_func (time_t (*func)(struct tm *))
+{
+  {
+    struct tm tmg =
+      {
+	.tm_sec = 0,
+	.tm_min = 0,
+	.tm_hour = 0,
+	.tm_mday = 1,
+	.tm_mon = 0,
+	.tm_year = 70,
+	.tm_wday = 4,
+	.tm_yday = 0,
+	.tm_isdst = 0
+     };
+     time_t t = func (&tmg);
+     TEST_COMPARE (t, 0);
+  }
+
+  {
+    struct tm tmg =
+      {
+	.tm_sec = 7,
+	.tm_min = 14,
+	.tm_hour = 3,
+	.tm_mday = 19,
+	.tm_mon = 0,
+	.tm_year = 138,
+	.tm_wday = 2,
+	.tm_yday = 18,
+	.tm_isdst = 0
+     };
+     time_t t = func (&tmg);
+     TEST_COMPARE (t, 0x7fffffff);
+  }
+
+  if (sizeof (time_t) < 8)
+    return;
+
+  {
+    struct tm tmg =
+      {
+	.tm_sec = 8,
+	.tm_min = 14,
+	.tm_hour = 3,
+	.tm_mday = 19,
+	.tm_mon = 0,
+	.tm_year = 138,
+	.tm_wday = 2,
+	.tm_yday = 18,
+	.tm_isdst = 0
+     };
+     time_t t = func (&tmg);
+     TEST_COMPARE (t, (time_t) 0x80000000ull);
+  }
+}
+
+static int
+do_test (void)
+{
+  do_test_func (timegm);
+
+  /* timelocal is an alias to mktime and behaves like timegm with the
+     difference that it takes timezone into account.  */
+  TEST_VERIFY_EXIT (setenv ("TZ", ":", 1) == 0);
+  tzset ();
+  do_test_func (timelocal);
+
+  return 0;
+}
+
+#include <support/test-driver.c>