test_when_finished mv commit-graph-backup $objdir/info/commit-graph &&
cp $objdir/info/commit-graph commit-graph-backup &&
printf "$data" | dd of="$objdir/info/commit-graph" bs=1 seek="$pos" conv=notrunc &&
- dd of="$objdir/info/commit-graph" bs=1 seek="$zero_pos" count=0 &&
+ dd of="$objdir/info/commit-graph" bs=1 seek="$zero_pos" if=/dev/null &&
generate_zero_bytes $(($orig_size - $zero_pos)) >>"$objdir/info/commit-graph" &&
test_must_fail git commit-graph verify 2>test_err &&
grep -v "^+" test_err >err &&