refactor: move app/util/* to app/lib/

spec/lib/message_dequeuer_spec.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe MessageDequeuer do
+  describe ".process" do
+    it "calls the initial process with the given message and logger" do
+      message = create(:queued_message)
+      logger = TestLogger.new
+
+      mock = double("InitialProcessor")
+      expect(mock).to receive(:process).with(no_args)
+      expect(MessageDequeuer::InitialProcessor).to receive(:new).with(message, logger: logger).and_return(mock)
+
+      described_class.process(message, logger: logger)
+    end
+  end
+end