assert that all containers are back up and running after backup

test/default/test.sh

@@ -13,6 +13,12 @@ docker run --rm -it \
   -v default_backup_data:/data alpine \
   ash -c 'tar -xf /data/backup/test.tar.gz && test -f /backup/app_data/offen.db'
 
+if [ "$(docker-compose ps -q | wc -l)" != "3" ]; then
+  echo "Expected all containers to be running post backup, instead seen:"
+  docker-compose ps
+  exit 1
+fi
+
 docker-compose down --volumes
 
 echo "Test passed"