test: top closure with mli only (ocaml#7081)

Signed-off-by: Rudi Grinberg <[email protected]>

test/blackbox-tests/test-cases/top-closed-mli-only.t

@@ -0,0 +1,49 @@
+This test demonstrates a dependency being pulled via an mli only module:
+
+  $ cat >dune-project <<EOF
+  > (lang dune 3.7)
+  > EOF
+
+  $ lib=foo
+
+  $ cat >dune <<EOF
+  > (library
+  >  (name $lib)
+  >  (wrapped false)
+  >  (modules_without_implementation uast))
+  > EOF
+
+  $ cat >identifier.ml <<EOF
+  > let create () = ()
+  > EOF
+  $ cat >identifier.mli <<EOF
+  > val create : unit -> unit
+  > EOF
+
+  $ cat >uast.mli <<EOF
+  > module Identifier = Identifier
+  > EOF
+
+  $ cat >upretty_printer.ml <<EOF
+  > let f () = Uast.Identifier.create ()
+  > EOF
+
+  $ mkdir bin
+  $ cat >bin/dune <<EOF
+  > (executable
+  >  (name use)
+  >  (libraries $lib))
+  > EOF
+
+  $ cat >bin/use.ml <<EOF
+  > let () = Upretty_printer.f ()
+  > EOF
+
+Build in development mode:
+
+  $ dune exec bin/use.exe
+
+And now in release
+
+  $ dune exec bin/use.exe --release 2>&1 | grep -v "cd _build"
+  [1]