Spec coverage and refactor of digest mailer worker (#2961)

app/workers/digest_mailer_worker.rb

@@ -5,10 +5,21 @@ class DigestMailerWorker
 
   sidekiq_options queue: 'mailers'
 
+  attr_reader :user
+
   def perform(user_id)
-    user = User.find(user_id)
-    return unless user.settings.notification_emails['digest']
+    @user = User.find(user_id)
+    deliver_digest if user_receives_digest?
+  end
+
+  private
+
+  def deliver_digest
     NotificationMailer.digest(user.account).deliver_now!
     user.touch(:last_emailed_at)
   end
+
+  def user_receives_digest?
+    user.settings.notification_emails['digest']
+  end
 end

spec/workers/digest_mailer_worker_spec.rb

+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe DigestMailerWorker do
+  describe 'perform' do
+    let(:user) { Fabricate(:user, last_emailed_at: 3.days.ago) }
+
+    context 'for a user who receives digests' do
+      it 'sends the email' do
+        service = double(deliver_now!: nil)
+        allow(NotificationMailer).to receive(:digest).and_return(service)
+        update_user_digest_setting(true)
+        described_class.perform_async(user.id)
+
+        expect(NotificationMailer).to have_received(:digest)
+        expect(user.reload.last_emailed_at).to be_within(1).of(Time.now.utc)
+      end
+    end
+
+    context 'for a user who does not receive digests' do
+      it 'does not send the email' do
+        allow(NotificationMailer).to receive(:digest)
+        update_user_digest_setting(false)
+        described_class.perform_async(user.id)
+
+        expect(NotificationMailer).not_to have_received(:digest)
+        expect(user.last_emailed_at).to be_within(1).of(3.days.ago)
+      end
+    end
+
+    def update_user_digest_setting(value)
+      user.settings['notification_emails'] = user.settings['notification_emails'].merge('digest' => value)
+    end
+  end
+end