Rails - framework for sending test emails and disable DB write - ruby-on-rails

Question

I have a website with several types of customer (eg Admin, Manager, Marketing, etc.)
Using Rails, I am asked to send test emails to those people so they can preview the emails on their own email client + firewall restrictions + see if the email go into the promotion folder or not. I need to be able to send a specific set of emails to each user type (such tests are very seldom, but ultimately any of our company admins should be able to send test emails using the frontend interface).
What I'm going for, it to write one class per user type, that would register the emails that this user is likely to receive at some point, and use (for example FactoryGirl) in build-only mode (no Writes to DB !!) to build the models needed to send the emails using deliver_now (so I avoid serialization/deserialization issues). I was hoping to be able to run this system in my real production environment (so that I can use my REAL email reputation, signatures, etc.)
Is there an easy way to disable DB writes (so I make sure all my example models are destroyed after their use to send an email ?) ? An easy option would be to boot up the server using readonly database credentials but maybe there is something safe that would avoid too much trouble.
Here is how my code looks like
module Testing
module Emails
class UserTypeAdmin < Base
attr_accessor, :new_user, :admin
register_email :created_new_user, type: :user_management do
UserManagementMailer.user_created(new_user, creator: admin)
end
def prepare_models
self.admin = FactoryGirl.build(:admin)
self.new_user = FactoryGirl.build(:user)
end
end
end
end
module Testing
module Emails
class Base
class < self
# my logic to register emails, definitions of #register_email, etc.
end
def initialize(tester_emails, ccs = [])
#tester_emails = tester_emails
#ccs = ccs
prepare_models
end
def send_email(email_name)
email = instance_eval(registered_emails(email_name))
email.to = #tester_emails
email.cc = #ccs
email.deliver_now
end
My FactoryGirls factories are quite messy and although I am using the :build methods, some factories were written using associations with the :create strategy so just to make sure, I'd like to lock the DB writes so I can easily prevent bad noise on my Database (I am using Mongoid so I don't have an easy transaction mechanism to cancel all my writes)

Answer 1

So one very simple solution is to write a spec that checks nothing is written to the DB. Using this I was able to debug a few cases where one model was persisted.
require 'rails_helper'
describe Testing::Email::UserTypeAdmin do
let(:tos) { ['admin#example.com'] }
let(:ccs) { ['adminmjg#example.com'] }
let(:tested_models) {[
User, Admin,
Conversation, Message, # etc.
]}
subject do
described_class.new(tos, ccs)
end
context 'testing all emails' do
it 'does nothing with the DB' do
subject.send_all_emails
aggregate_failures 'no persistence' do
tested_models.each do |model|
expect(model.count).to eq(0), "#{model.name} was persisted"
end
end
end
end
end
I'm still on the lookout for better solutions :-)