From 8771957703cf4f8d71f2d04ef0614d2aeb0c65ee Mon Sep 17 00:00:00 2001
From: =?utf8?q?P=C3=A1draig=20Brady?= <P@draigBrady.com>
Date: Tue, 1 Jul 2025 22:52:16 +0100
Subject: [PATCH] tests: cat: add test for O_APPEND bug fix

* tests/cat/cat-self.sh: Add a test case
for commit v9.6-19-g7386c291b
---
 tests/cat/cat-self.sh | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tests/cat/cat-self.sh b/tests/cat/cat-self.sh
index 3c171b40b2..2d09fc0877 100755
--- a/tests/cat/cat-self.sh
+++ b/tests/cat/cat-self.sh
@@ -50,4 +50,14 @@ returns_ 1 cat - fx4 <fx 1<>fx4 || fail=1
 returns_ 1 cat fx5 >>fx5 || fail=1
 returns_ 1 cat <fx6 >>fx6 || fail=1
 
+# coreutils 9.6 would fail with a plain cat if the tty was in append mode
+# Simulate with a regular file to simplify
+echo foo > file || framework_failure_
+# Set fd 3 at EOF
+exec 3< file && cat <&3 > /dev/null || framework_failure_
+# Set fd 4 in append mode
+exec 4>> file || framework_failure_
+cat <&3 >&4 || fail=1
+exec 3<&- 4>&-
+
 Exit $fail
-- 
2.47.3