Spec for private messages not to be included in mails (#837)

spec/mailers/conversation_reply_mailer_spec.rb

@@ -12,15 +12,31 @@ RSpec.describe ConversationReplyMailer, type: :mailer do
       allow(class_instance).to receive(:smtp_config_set_or_development?).and_return(true)
     end
 
-    context 'when custom domain and email is not enabled' do
+    context 'with all mails' do
       let(:conversation) { create(:conversation, assignee: agent) }
       let(:message) { create(:message, conversation: conversation) }
+      let(:private_message) { create(:message, content: 'This is a private message', private: true, conversation: conversation) }
       let(:mail) { described_class.reply_with_summary(message.conversation, Time.zone.now).deliver_now }
 
       it 'renders the subject' do
         expect(mail.subject).to eq("[##{message.conversation.display_id}] #{message.content.truncate(30)}")
       end
 
+      it 'not have private notes' do
+        # make the message private
+        private_message.private = true
+        private_message.save
+
+        expect(mail.body.decoded).not_to include(private_message.content)
+        expect(mail.body.decoded).to include(message.content)
+      end
+    end
+
+    context 'when custom domain and email is not enabled' do
+      let(:conversation) { create(:conversation, assignee: agent) }
+      let(:message) { create(:message, conversation: conversation) }
+      let(:mail) { described_class.reply_with_summary(message.conversation, Time.zone.now).deliver_now }
+
       it 'renders the receiver email' do
         expect(mail.to).to eq([message&.conversation&.contact&.email])
       end