test(pkg): reproduce not finding the patch file

Signed-off-by: Alpha DIALLO <moyodiallo@gmail.com>

test/blackbox-tests/test-cases/pkg/ocamlformat/patch-extra-files.t

@@ -0,0 +1,82 @@
+This is current bug, 'dune fmt' misses "dev-tools.locks" directory for the first run.
+
+  $ . ./helpers.sh
+  $ mkrepo
+
+Make a fake ocamlformat:
+  $ mkdir ocamlformat
+  $ cd ocamlformat
+  $ cat > dune-project <<EOF
+  > (lang dune 3.13)
+  > (package (name ocamlformat))
+  > EOF
+  $ cat > ocamlformat.ml <<EOF
+  > let () = print_string "Hello"
+  > EOF
+  $ cat > dune <<EOF
+  > (executable
+  >  (public_name ocamlformat))
+  > EOF
+  $ cd ..
+  $ tar -czf ocamlformat.tar.gz ocamlformat
+  $ rm -rf ocamlformat
+
+  $ cat > patch-for-ocamlformat.patch <<EOF
+  > diff a/ocamlformat.ml b/ocamlformat.ml
+  > --- a/ocamlformat.ml
+  > +++ b/ocamlformat.ml
+  > @@ -1,1 +1,1 @@
+  > -let () = print_string "Hello"
+  > +let () = print_string "Ocamlformat"
+  > EOF
+
+
+Make the ocamlformat opam package which uses a patch:
+  $ mkpkg ocamlformat "0.26.2"  <<EOF
+  > build: [
+  >   [
+  >     "dune"
+  >     "build"
+  >     "-p"
+  >     name
+  >     "-j"
+  >     jobs
+  >   ]
+  > ]
+  > extra-files: ["patch-for-ocamlformat.patch" "md5=$(md5sum patch-for-ocamlformat.patch | cut -f1 -d' ')"]
+  > patches: ["patch-for-ocamlformat.patch"]
+  > url {
+  >  src:"file://$PWD/ocamlformat.tar.gz"
+  >  checksum: [
+  >   "md5=$(md5sum ocamlformat.tar.gz | cut -f1 -d' ')"
+  >  ]
+  > }
+  > EOF
+  $ mkdir -p mock-opam-repository/packages/ocamlformat/ocamlformat.0.26.2/files/
+  $ cp patch-for-ocamlformat.patch mock-opam-repository/packages/ocamlformat/ocamlformat.0.26.2/files/
+
+Make a project that uses the fake ocamlformat:
+  $ make_project_with_dev_tool_lockdir
+
+First time run
+  $ DUNE_CONFIG__LOCK_DEV_TOOL=enabled dune fmt 2>&1 | sed -E 's#.*.sandbox/[^/]+#.sandbox/$SANDBOX#g'
+  Solution for dev-tools.locks/ocamlformat:
+  - ocamlformat.0.26.2
+  Error:
+  .sandbox/$SANDBOX/_private/default/.dev-tool/ocamlformat/ocamlformat/source/patch-for-ocamlformat.patch:
+  No such file or directory
+  -> required by
+     _build/_private/default/.dev-tool/ocamlformat/ocamlformat/target/bin/ocamlformat
+  -> required by _build/default/.formatted/foo.ml
+  -> required by alias .formatted/fmt
+  -> required by alias fmt
+
+Second time run
+  $ DUNE_CONFIG__LOCK_DEV_TOOL=enabled dune fmt
+  File "foo.ml", line 1, characters 0-0:
+  Error: Files _build/default/foo.ml and _build/default/.formatted/foo.ml
+  differ.
+  Promoting _build/default/.formatted/foo.ml to foo.ml.
+  [1]
+  $ cat foo.ml
+  Ocamlformat