Alter priority of Delete activities to be lowest

This will prevent a user with a large number of posts from negatively affecting performance of the outgoing federation queue if they delete their account.

test/pleroma/workers/publisher_worker_test.exs

@@ -0,0 +1,40 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Workers.PublisherWorkerTest do
+  use Pleroma.DataCase, async: true
+  use Oban.Testing, repo: Pleroma.Repo
+
+  import Pleroma.Factory
+
+  alias Pleroma.Object
+  alias Pleroma.Web.ActivityPub.ActivityPub
+  alias Pleroma.Web.ActivityPub.Builder
+  alias Pleroma.Web.CommonAPI
+  alias Pleroma.Web.Federator
+
+  describe "Oban job priority:" do
+    setup do
+      user = insert(:user)
+
+      {:ok, post} = CommonAPI.post(user, %{status: "Regrettable post"})
+      object = Object.normalize(post, fetch: false)
+      {:ok, delete_data, _meta} = Builder.delete(user, object.data["id"])
+      {:ok, delete, _meta} = ActivityPub.persist(delete_data, local: true)
+
+      %{
+        post: post,
+        delete: delete
+      }
+    end
+
+    test "Deletions are lower priority", %{delete: delete} do
+      assert {:ok, %Oban.Job{priority: 3}} = Federator.publish(delete)
+    end
+
+    test "Creates are normal priority", %{post: post} do
+      assert {:ok, %Oban.Job{priority: 0}} = Federator.publish(post)
+    end
+  end
+end