Add test to check /object/:id does not leak the tombstone itself

test/web/ostatus/ostatus_controller_test.exs

@@ -1,7 +1,7 @@
 defmodule Pleroma.Web.OStatus.OStatusControllerTest do
   use Pleroma.Web.ConnCase
   import Pleroma.Factory
-  alias Pleroma.{User, Repo}
+  alias Pleroma.{User, Repo, Object}
   alias Pleroma.Web.CommonAPI
   alias Pleroma.Web.OStatus.ActivityRepresenter
 
@@ -110,6 +110,22 @@ defmodule Pleroma.Web.OStatus.OStatusControllerTest do
     |> response(404)
   end
 
+  test "404s on deleted objects", %{conn: conn} do
+    note_activity = insert(:note_activity)
+    [_, uuid] = hd(Regex.scan(~r/.+\/([\w-]+)$/, note_activity.data["object"]["id"]))
+    object = Object.get_by_ap_id(note_activity.data["object"]["id"])
+
+    conn
+    |> get("/objects/#{uuid}")
+    |> response(200)
+
+    Object.delete(object)
+
+    conn
+    |> get("/objects/#{uuid}")
+    |> response(404)
+  end
+
   test "gets an activity", %{conn: conn} do
     note_activity = insert(:note_activity)
     [_, uuid] = hd(Regex.scan(~r/.+\/([\w-]+)$/, note_activity.data["id"]))