Recycle "stdlib" test

Author: voodoos

tests/test-dirs/locate/functors/f-test-ml-mli.t

@@ -0,0 +1,50 @@
+  $ cat >dune-project <<EOF
+  > (lang dune 2.0)
+  > EOF
+
+  $ cat >mySet.mli <<EOF
+  > module Make : functor (Arg : sig type t end) -> sig
+  >   type t
+  > end
+  > EOF
+
+  $ cat >mySet.ml <<EOF
+  > module Make (Arg : sig type t end) = struct
+  >   type t = Arg.t
+  > end
+  > EOF
+
+  $ cat >s.ml <<EOF
+  > module Foo = MySet.Make(struct
+  >   type t
+  > end)
+  > type t = Foo.t
+  > EOF
+
+  $ cat >dune <<EOF
+  > (executable (name s))
+  > EOF
+
+  $ dune build @check
+
+Should jump to mySet.ml:
+  $ $MERLIN single locate -look-for ml -position 4:13 \
+  > -filename ./s.ml < ./s.ml | jq '.value'
+  {
+    "file": "$TESTCASE_ROOT/mySet.ml",
+    "pos": {
+      "line": 2,
+      "col": 2
+    }
+  }
+
+Should jump to mySet.mli:
+  $ $MERLIN single locate -look-for mli -position 4:13 \
+  > -filename ./s.ml < ./s.ml | jq '.value'
+  {
+    "file": "$TESTCASE_ROOT/mySet.mli",
+    "pos": {
+      "line": 2,
+      "col": 2
+    }
+  }