diff --git a/.gitignore b/.gitignore
index a6be0f00f..285b28d63 100644
--- a/.gitignore
+++ b/.gitignore
@@ -206,6 +206,7 @@ Makefile.in
 /fish/stamp-virt-copy-out.pod
 /fish/stamp-virt-tar-in.pod
 /fish/stamp-virt-tar-out.pod
+/fish/test-prep.sh
 /fish/virt-copy-in.1
 /fish/virt-copy-out.1
 /fish/virt-tar-in.1
diff --git a/fish/test-prep.sh b/fish/test-prep.sh
deleted file mode 100755
index e2b972abc..000000000
--- a/fish/test-prep.sh
+++ /dev/null
@@ -1,35 +0,0 @@
-#!/bin/bash -
-# libguestfs
-# Copyright (C) 2012 Red Hat Inc.
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
-
-set -e
-
-rm -f prep*.img
-
-# It would be nice if we could keep this automatically in sync
-# with the prepared disk types.  XXX
-$VG guestfish \
-    -N prep1.img=disk \
-    -N prep2.img=part \
-    -N prep3.img=fs \
-    -N prep4.img=lv:/dev/VG1/LV \
-    -N prep5.img=lvfs:/dev/VG2/LV \
-    -N prep6.img=bootroot \
-    -N prep7.img=bootrootlv:/dev/VG3/LV \
-    exit
-
-rm prep*.img
diff --git a/generator/fish.ml b/generator/fish.ml
index 646674df7..980f55f6b 100644
--- a/generator/fish.ml
+++ b/generator/fish.ml
@@ -1106,3 +1106,36 @@ event_bitmask_of_event_set (const char *arg, uint64_t *eventset_r)
   return 0;
 }
 "
+
+and generate_fish_test_prep_sh () =
+  pr "#!/bin/bash -\n";
+  generate_header HashStyle GPLv2plus;
+
+  let all_disks = sprintf "prep{1..%d}.img" (List.length prepopts) in
+
+  pr "\
+set -e
+
+rm -f %s
+
+$VG guestfish \\
+" all_disks;
+
+  let vg_count = ref 0 in
+
+  iteri (
+    fun i (name, _, _, _) ->
+      let params = [name] in
+      let params =
+        if find name "lv" <> -1 then (
+          incr vg_count;
+          sprintf "/dev/VG%d/LV" !vg_count :: params
+        ) else params in
+      let params = List.rev params in
+      pr "    -N prep%d.img=%s \\\n" (i + 1) (String.concat ":" params)
+  ) prepopts;
+
+  pr "    exit
+
+rm %s
+" all_disks
diff --git a/generator/fish.mli b/generator/fish.mli
index c654bf6bf..bb4376aaa 100644
--- a/generator/fish.mli
+++ b/generator/fish.mli
@@ -26,3 +26,4 @@ val generate_fish_event_names : unit -> unit
 val generate_fish_prep_options_c : unit -> unit
 val generate_fish_prep_options_h : unit -> unit
 val generate_fish_prep_options_pod : unit -> unit
+val generate_fish_test_prep_sh : unit -> unit
diff --git a/generator/main.ml b/generator/main.ml
index 8d08d8395..91ca4d79c 100644
--- a/generator/main.ml
+++ b/generator/main.ml
@@ -124,6 +124,7 @@ Run it from the top source directory using the command
   output_to "fish/prepopts.c" generate_fish_prep_options_c;
   output_to "fish/prepopts.h" generate_fish_prep_options_h;
   output_to "fish/guestfish-prepopts.pod" generate_fish_prep_options_pod;
+  output_to ~perm:0o555 "fish/test-prep.sh" generate_fish_test_prep_sh;
   output_to "ocaml/guestfs.mli" generate_ocaml_mli;
   output_to "ocaml/guestfs.ml" generate_ocaml_ml;
   output_to "ocaml/guestfs-c-actions.c" generate_ocaml_c;