diff --git a/src/climate.mli b/src/climate.mli
index 996b5b7..b6e4468 100644
--- a/src/climate.mli
+++ b/src/climate.mli
@@ -219,7 +219,10 @@ module Command : sig
 
   (** A command that has the side effect of printing the completion
       script of the entire command it's contained inside. It's safe to
-      bury this inside a hidden command group of internal commands. *)
+      bury this inside a hidden command group of internal
+      commands. The command takes some arguments to configure the
+      generated completion script, similar to the arguments of the
+      function [completion_script_bash]. *)
   val print_completion_script_bash : _ t
 
   (** Returns a bash script that can be sourced in a shell to register
diff --git a/tests/completion_tests/basic/main.ml b/tests/completion_tests/basic/basic.ml
similarity index 100%
rename from tests/completion_tests/basic/main.ml
rename to tests/completion_tests/basic/basic.ml
diff --git a/tests/completion_tests/basic/dune b/tests/completion_tests/basic/dune
index e36f3f6..3e4d343 100644
--- a/tests/completion_tests/basic/dune
+++ b/tests/completion_tests/basic/dune
@@ -1,6 +1,6 @@
 (executable
- (public_name main)
+ (public_name basic)
  (libraries climate))
 
 (cram
- (deps main.exe))
+ (deps basic.exe))
diff --git a/tests/completion_tests/basic/test.t b/tests/completion_tests/basic/test.t
index b761e0c..9b072d9 100644
--- a/tests/completion_tests/basic/test.t
+++ b/tests/completion_tests/basic/test.t
@@ -1,4 +1,4 @@
-  $ ./main.exe > completion.sh
+  $ ./basic.exe > completion.sh
   $ x() { ../print_completions.sh ./completion.sh _basic_complete "$1" "$2"; }
 
   $ x "basic " \
diff --git a/tests/completion_tests/fake_git/dune b/tests/completion_tests/fake_git/dune
new file mode 100644
index 0000000..09de433
--- /dev/null
+++ b/tests/completion_tests/fake_git/dune
@@ -0,0 +1,6 @@
+(executable
+ (public_name fake_git)
+ (libraries climate unix))
+
+(cram
+ (deps fake_git.exe))
diff --git a/tests/completion_tests/fake_git/fake_git.ml b/tests/completion_tests/fake_git/fake_git.ml
new file mode 100644
index 0000000..34d0288
--- /dev/null
+++ b/tests/completion_tests/fake_git/fake_git.ml
@@ -0,0 +1,74 @@
+open Climate
+
+let ls dir =
+  let dir_handle = Unix.opendir dir in
+  let rec loop files =
+    try
+      let file = Unix.readdir dir_handle in
+      loop (file :: files)
+    with
+    | End_of_file -> files
+  in
+  List.rev (loop [])
+;;
+
+(* Fake protocol for defining branches so the list of branches can be
+   updated dynamically by tests. *)
+let list_branches () =
+  ls "./.git/branches"
+  |> List.filter (Fun.negate @@ String.starts_with ~prefix:".")
+  |> List.sort String.compare
+;;
+
+let branch_conv =
+  let open Arg_parser in
+  { string with
+    default_value_name = "BRANCH"
+  ; completion = Some (Completion.reentrant_thunk list_branches)
+  }
+;;
+
+(* A command which mixes reentrant completion with file completion *)
+let checkout =
+  let open Arg_parser in
+  let+ _create_branch = flag [ "b" ]
+  and+ _branch_name = pos_req 0 branch_conv
+  and+ _files = pos_right 1 file in
+  ()
+;;
+
+(* A command which mixes reentrant completion with a named argument
+   with a value completed with an enum *)
+let log =
+  let open Arg_parser in
+  let+ _pretty =
+    named_opt [ "pretty"; "p" ] (string_enum [ "full"; "fuller"; "short"; "oneline" ])
+  and+ _branch_name = pos_req 0 branch_conv in
+  ()
+;;
+
+(* A command which mixes positional arguments and subcommands *)
+let bisect op =
+  let open Arg_parser in
+  match op with
+  | `Mark ->
+    let+ _status = pos_opt 0 (string_enum [ "good"; "bad" ]) in
+    ()
+  | `Start | `Reset -> unit
+;;
+
+let () =
+  let open Command in
+  group
+    [ subcommand "checkout" (singleton checkout)
+    ; subcommand "log" (singleton log)
+    ; subcommand "bisect"
+      @@ group
+           ~default_arg_parser:(bisect `Mark)
+           [ subcommand "start" (singleton (bisect `Start))
+           ; subcommand "reset" (singleton (bisect `Reset))
+           ]
+    ; subcommand "completions" ~hidden:true print_completion_script_bash
+    ]
+  |> run
+;;
diff --git a/tests/completion_tests/fake_git/test.t b/tests/completion_tests/fake_git/test.t
new file mode 100644
index 0000000..fe2ff8b
--- /dev/null
+++ b/tests/completion_tests/fake_git/test.t
@@ -0,0 +1,101 @@
+  $ ./fake_git.exe completions --program-name=fake-git --global-symbol-prefix=_fake_git_ > completion.sh
+  $ x() { ../print_completions.sh ./completion.sh _fake_git_complete "$1" "$2"; }
+
+Make a fake .git directory with some branches.
+  $ mkdir -p .git/branches
+  $ touch .git/branches/foo
+  $ touch .git/branches/bar
+
+  $ x "fake-git " \
+  >   "         ^"
+  checkout
+  log
+  bisect
+
+  $ x "fake-git checkout " \
+  >   "                  ^"
+  bar
+  foo
+
+  $ x "fake-git checkout foo " \
+  >   "                      ^"
+  .git
+  completion.sh
+  fake_git.exe
+
+  $ x "fake-git checkout foo a.txt " \
+  >   "                            ^"
+  .git
+  completion.sh
+  fake_git.exe
+
+  $ x "fake-git checkout foo a.txt " \
+  >   "                  ^         "
+  bar
+  foo
+
+  $ x "fake-git checkout foo a.txt " \
+  >   "                      ^     "
+  .git
+  completion.sh
+  fake_git.exe
+
+  $ x "fake-git log " \
+  >   "             ^"
+  bar
+  foo
+
+  $ x "fake-git log -" \
+  >   "              ^"
+  --help
+  --pretty
+  -h
+  -p
+
+  $ x "fake-git log --" \
+  >   "               ^"
+  --help
+  --pretty
+
+  $ x "fake-git log --pretty " \
+  >   "                      ^"
+  full
+  fuller
+  short
+  oneline
+
+  $ x "fake-git log --pretty f" \
+  >   "                       ^"
+  full
+  fuller
+
+  $ x "fake-git log --pretty full " \
+  >   "                           ^"
+  bar
+  foo
+
+
+  $ x "fake-git log --pretty full foo " \
+  >   "                               ^"
+  --help
+  --pretty
+  -h
+  -p
+
+Test that positional arguments and subcommands are both listed.
+  $ x "fake-git bisect " \
+  >   "                ^"
+  start
+  reset
+  good
+  bad
+
+  $ x "fake-git bisect -" \
+  >   "                 ^"
+  --help
+  -h
+
+  $ x "fake-git bisect start " \
+  >   "                      ^"
+  --help
+  -h