1 files changed, 44 insertions, 0 deletions
diff --git a/tests/head/head-pos.sh b/tests/head/head-pos.sh
new file mode 100755
index 0000000..c24edd1
--- /dev/null
+++ b/tests/head/head-pos.sh
@@ -0,0 +1,44 @@
+#!/bin/sh
+# When reading a specified number of lines, ensure that the output
+# file pointer is positioned just after those lines.
+
+# Copyright (C) 2002-2023 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/>.
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+print_ver_ head
+
+(echo a; echo b) > in || framework_failure_
+echo b > exp || framework_failure_
+
+for i in -1 1; do
+  (head -n $i >/dev/null; cat) < in > out || fail=1
+  compare exp out || fail=1
+done
+
+# Exercise the (start_pos < pos) block in elide_tail_lines_seekable.
+# So far, this is the only test to do that.
+# Do that by creating a file larger than BUFSIZ (I've seen 128K) and
+# elide a suffix of it (by line count) that is also larger than BUFSIZ.
+# 50000 lines times 6 bytes per line gives us enough leeway even on a
+# system with a BUFSIZ of 256K.
+n_lines=50000
+seq 70000 > in2 || framework_failure_
+echo $n_lines > exp-n || framework_failure_
+
+(head -n-$n_lines>/dev/null; wc -l) < in2 > n
+compare exp-n n || fail=1
+
+Exit $fail