From 29cee19e18db29c355b6408c09d3fef51b64f71d Mon Sep 17 00:00:00 2001
From: Collin Funk <collin.funk1@gmail.com>
Date: Sun, 25 Jan 2026 22:56:47 -0800
Subject: [PATCH] tests: date: test that %% in the string is not replaced

* tests/date/percent-percent.sh: New file.
* tests/local.mk (all_tests): Add it.
---
 tests/date/percent-percent.sh | 36 +++++++++++++++++++++++++++++++++++
 tests/local.mk                |  1 +
 2 files changed, 37 insertions(+)
 create mode 100755 tests/date/percent-percent.sh

diff --git a/tests/date/percent-percent.sh b/tests/date/percent-percent.sh
new file mode 100755
index 0000000000..998791c0e4
--- /dev/null
+++ b/tests/date/percent-percent.sh
@@ -0,0 +1,36 @@
+#!/bin/sh
+# Test that 'date' does not mishandle %% in the format string.
+
+# Copyright (C) 2026 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/>.
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+print_ver_ date
+
+for loc in C "$LOCALE_FR" "$LOCALE_FR_UTF8"; do
+  test -z "$loc" && continue
+  # Time conversion specifiers.
+  fmt=$(echo HIklMNpPrRsSTXzZ | sed 's/./%%&/g') || framework_failure_
+  echo $fmt | sed 's/%%/%/g' > exp || framework_failure_
+  LC_ALL="$loc" date +"$fmt" > out || fail=1
+  compare exp out || fail=1
+  # Date conversion specifiers.
+  fmt=$(echo aAbBcCdDeFgGhjmuUVwWxyY | sed 's/./%%&/g') || framework_failure_
+  echo $fmt | sed 's/%%/%/g' > exp || framework_failure_
+  LC_ALL="$loc" date +"$fmt" > out || fail=1
+  compare exp out || fail=1
+done
+
+Exit $fail
diff --git a/tests/local.mk b/tests/local.mk
index 607901c6a6..e3372354c8 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -326,6 +326,7 @@ all_tests =					\
   tests/date/date-ethiopia.sh			\
   tests/date/date-iran.sh			\
   tests/date/date-locale-hour.sh		\
+  tests/date/percent-percent.sh			\
   tests/date/reference.sh			\
   tests/date/resolution.sh			\
   tests/date/date-sec.sh			\
-- 
2.47.3