From ddb3db2050ef5d7f09e9c16ecd227c162430fde2 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers3@gmail.com>
Date: Sun, 18 Oct 2020 14:21:25 -0700
Subject: [PATCH] scripts/gzip_tests.sh: skip if GNU gzip/gunzip is too old

---
 scripts/gzip_tests.sh | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/scripts/gzip_tests.sh b/scripts/gzip_tests.sh
index f29dbf8..8d806b1 100755
--- a/scripts/gzip_tests.sh
+++ b/scripts/gzip_tests.sh
@@ -96,6 +96,24 @@ assert_equals() {
 # Get the filesystem type.
 FSTYPE=$(df -T . | tail -1 | awk '{print $2}')
 
+# If gzip or gunzip is the GNU version, require that it supports the '-k'
+# option.  This option was added in v1.6, released in 2013.
+check_version_prereq() {
+	local prog=$1
+
+	if ! echo | { $prog -k || true; } |& grep -q 'invalid option'; then
+		return 0
+	fi
+	if ! $prog -V |& grep -q 'Free Software Foundation'; then
+		echo 1>&2 "Unexpected case: not GNU $prog, but -k option is invalid"
+		exit 1
+	fi
+	echo "GNU $prog is too old; skipping gzip/gunzip tests"
+	exit 0
+}
+check_version_prereq gzip
+check_version_prereq gunzip
+
 begin_test 'Basic compression and decompression works'
 cp file orig
 gzip file