diff --git a/cogent/tests/pass_ticket-e31.cogent b/cogent/tests/pass_ticket-e31.cogent
index f39d4e1d6..988482197 100644
--- a/cogent/tests/pass_ticket-e31.cogent
+++ b/cogent/tests/pass_ticket-e31.cogent
@@ -1,15 +1,5 @@
-type MountState
+type OstoreState
 
-type Buffer
-type UbiVol
-type OstoreState = {
-  next_inum : U32
-, rbuf : Buffer
-, wbuf_eb : U32
-, ubi_vol : UbiVol
-}
-
-type ObjId = U64
 type Obj
 
 type R a b = <Success a | Error b>
@@ -17,23 +7,20 @@ type RR c a b = (c, R a b)
 
 type BufOffs = U32
 deep_freeObj: Obj -> ()
-deserialise_Obj: (Buffer!, BufOffs) -> (Obj, BufOffs)
-read_obj_pages_in_buf: (MountState!, UbiVol!, Buffer, ObjAddr!) -> Buffer
+get_Obj : () -> Obj
 
-type ObjAddr = #{ ebnum : U32, offs : U32, len : U32, sqnum : U64 }
+type ObjAddr
 index_get_addr : () -> ObjAddr
 
 success : all (a, b). a -> R a b
 success a = Success a
 
-ostore_read: (MountState!, OstoreState, ObjId) -> RR OstoreState Obj ()
-ostore_read (mount_st, ostore_st, oid) =
+ostore_read: OstoreState -> RR OstoreState Obj ()
+ostore_read ostore_st =
   let addr = index_get_addr ()
   and (ostore_st, r) = 
-     let ostore_st {rbuf} = ostore_st
-     and rbuf = read_obj_pages_in_buf (mount_st, ostore_st.ubi_vol, rbuf, addr) !ostore_st
-     and (obj, sz) = deserialise_Obj (rbuf, 1) !rbuf
-      in (ostore_st {rbuf}, success obj)
+     let obj = get_Obj ()
+      in (ostore_st, success obj)
   in r
   | Success obj -> let _ = deep_freeObj obj in (ostore_st, Error)
   | Error -> (ostore_st, Error)