Update backup test script

baas2-backuptest-prod-1.sunet.se/overlay/opt/backuptest/gen-backup-files

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+
+set -eu
+
+date_ts=$(date +%s)
+backupdir=/opt/backuptest
+static_file=$backupdir/file-static-1
+append_file=$backupdir/file-append-1
+checksums_file=$backupdir/checksums.sha256
+ts_file=$backupdir/file-ts-$date_ts
+
+if ! [ -f $static_file ]; then
+  echo "static" > $static_file
+fi
+
+echo "$date_ts" >> $append_file
+
+echo "$date_ts" > "$ts_file"
+
+cd $backupdir
+sha256sum file-* > $checksums_file