Try having sync_reactions_count as a background job (#18991)

* Try having sync_reactable as a background job

* Update test

* Fix flakey test (order should not matter)

app/models/reaction.rb

@@ -49,7 +49,7 @@ class Reaction < ApplicationRecord
   before_save :assign_points
   after_create :notify_slack_channel_about_vomit_reaction, if: -> { category == "vomit" }
   before_destroy :bust_reactable_cache_without_delay
-  before_destroy :update_reactable_without_delay, unless: :destroyed_by_association
+  before_destroy :update_reactable, unless: :destroyed_by_association
   after_commit :async_bust
   after_commit :bust_reactable_cache, :update_reactable, on: %i[create update]
   after_commit :record_field_test_event, on: %i[create]
@@ -194,10 +194,6 @@ class Reaction < ApplicationRecord
     Reactions::BustReactableCacheWorker.new.perform(id)
   end
 
-  def update_reactable_without_delay
-    Reactions::UpdateRelevantScoresWorker.new.perform(id)
-  end
-
   def reading_time
     reactable.reading_time if category == "readinglist"
   end

spec/models/reaction_spec.rb

@@ -139,10 +139,10 @@ RSpec.describe Reaction do
 
       expected_result = [
         { category: "like", count: 1 },
-        { category: "unicorn", count: 1 },
         { category: "readinglist", count: 0 },
+        { category: "unicorn", count: 1 },
       ]
-      expect(described_class.count_for_article(article.id)).to eq(expected_result)
+      expect(described_class.count_for_article(article.id)).to contain_exactly(*expected_result)
     end
   end
 
@@ -234,7 +234,7 @@ RSpec.describe Reaction do
   end
 
   context "when callbacks are called before destroy" do
-    let(:reaction) { create(:reaction, reactable: article, user: user) }
+    let!(:reaction) { create(:reaction, reactable: article, user: user) }
 
     it "enqueues a ScoreCalcWorker on article reaction destroy" do
       sidekiq_assert_enqueued_with(job: Articles::ScoreCalcWorker, args: [article.id]) do
@@ -242,10 +242,10 @@ RSpec.describe Reaction do
       end
     end
 
-    it "updates reactable without delay" do
-      allow(reaction).to receive(:update_reactable_without_delay)
+    it "updates reactable with delay" do
+      allow(Reactions::UpdateRelevantScoresWorker).to receive(:perform_async)
       reaction.destroy
-      expect(reaction).to have_received(:update_reactable_without_delay)
+      expect(Reactions::UpdateRelevantScoresWorker).to have_received(:perform_async)
     end
 
     it "busts reactable cache without delay" do