Fix tests not passing in Opam (#2635)

Bug introduced in #2618.
The tests don't pass when run with `dune build -p` option, as it's done
in Opam.

Author: Julow

Diff for: test/passing/gen/dune.inc

@@ -106,18 +106,21 @@ let emit_test test_name setup =
   Printf.printf
     {|
 (rule
- (deps .ocamlformat dune-project)%s
+ (deps .ocamlformat .hg)%s
+ (package ocamlformat)
  (action
   (with-stdout-to %s
    (with-stderr-to %s.stderr
      %s))))
 
 (rule
  (alias runtest)%s
+ (package ocamlformat)
  (action (diff %s %s.stdout)))
 
 (rule
  (alias runtest)%s
+ (package ocamlformat)
  (action (diff %s %s.stderr)))
 |}
     enabled_if_line output_fname test_name

Diff for: test/passing/gen/gen.ml

@@ -0,0 +1,2 @@
+This file ensures that OCamlformat don't consider parent directories when
+searching for configuration.

Diff for: test/passing/refs.default/.hg

@@ -0,0 +1,2 @@
+This file ensures that OCamlformat don't consider parent directories when
+searching for configuration.

Diff for: test/passing/refs.default/dune-project

@@ -0,0 +1,2 @@
+This file ensures that OCamlformat don't consider parent directories when
+searching for configuration.