add formula tests
diff --git a/README.rst b/README.rst
index 7c8fbce..177b214 100644
--- a/README.rst
+++ b/README.rst
@@ -22,7 +22,7 @@
             fsid: 00000000-0000-0000-0000-000000000000
             mon initial members: ceph1,ceph2,ceph3
             mon host: 10.103.255.252:6789,10.103.255.253:6789,10.103.255.254:6789
-            osd_fs_mkfs_arguments_xfs:[]
+            osd_fs_mkfs_arguments_xfs:
             osd_fs_mount_options_xfs: rw,noatime
             network public: 10.0.0.0/24
             network cluster: 10.0.0.0/24
@@ -49,7 +49,7 @@
             fsid: 00000000-0000-0000-0000-000000000000
             mon initial members: ceph1,ceph2,ceph3
             mon host: 10.103.255.252:6789,10.103.255.253:6789,10.103.255.254:6789
-            osd_fs_mkfs_arguments_xfs:[]
+            osd_fs_mkfs_arguments_xfs:
             osd_fs_mount_options_xfs: rw,noatime
             network public: 10.0.0.0/24
             network cluster: 10.0.0.0/24
@@ -76,7 +76,7 @@
             fsid: 00000000-0000-0000-0000-000000000000
             mon initial members: ceph1,ceph2,ceph3
             mon host: 10.103.255.252:6789,10.103.255.253:6789,10.103.255.254:6789
-            osd_fs_mkfs_arguments_xfs:[]
+            osd_fs_mkfs_arguments_xfs:
             osd_fs_mount_options_xfs: rw,noatime
             network public: 10.0.0.0/24
             network cluster: 10.0.0.0/24