feat: Tag agents in a private note (#1688)

Co-authored-by: Sojan <sojan@pepalo.com>

spec/mailers/agent_notifications/conversation_notifications_mailer_spec.rb

@@ -4,8 +4,9 @@ require 'rails_helper'
 
 RSpec.describe AgentNotifications::ConversationNotificationsMailer, type: :mailer do
   let(:class_instance) { described_class.new }
-  let(:agent) { create(:user, email: 'agent1@example.com') }
-  let(:conversation) { create(:conversation, assignee: agent) }
+  let!(:account) { create(:account) }
+  let(:agent) { create(:user, email: 'agent1@example.com', account: account) }
+  let(:conversation) { create(:conversation, assignee: agent, account: account) }
 
   before do
     allow(described_class).to receive(:new).and_return(class_instance)
@@ -37,6 +38,19 @@ RSpec.describe AgentNotifications::ConversationNotificationsMailer, type: :maile
     end
   end
 
+  describe 'conversation_mention' do
+    let(:message) { create(:message, conversation: conversation, account: account) }
+    let(:mail) { described_class.conversation_mention(message, agent).deliver_now }
+
+    it 'renders the subject' do
+      expect(mail.subject).to eq("#{agent.available_name}, You have been mentioned in conversation [ID - #{conversation.display_id}]")
+    end
+
+    it 'renders the receiver email' do
+      expect(mail.to).to eq([agent.email])
+    end
+  end
+
   describe 'assigned_conversation_new_message' do
     let(:mail) { described_class.assigned_conversation_new_message(conversation, agent).deliver_now }