deliver_now in action mailer objects bugreport https://github.com/rails/rails/issues/17965

rr42_action_mailer_deliver.rb

unless File.exist?('Gemfile')
  File.write('Gemfile', <<-GEMFILE)
    source 'https://rubygems.org'
    #gem 'rails', github: 'rails/rails', branch: '4-2-stable'
    gem 'rails', '4.2.0.rc2'
    #gem 'rails', '4.1.8'
    
    #gem 'arel', github: 'rails/arel'
    #gem 'rack', github: 'rack/rack'
    gem 'i18n', github: 'svenfuchs/i18n'
    gem 'byebug'
  GEMFILE

  system 'bundle'
end
require 'byebug'
require 'bundler'
Bundler.setup(:default)

require 'rails'
require 'action_controller/railtie'
require 'action_mailer/railtie'

class TestApp < Rails::Application
  config.root = File.dirname(__FILE__)
  config.session_store :cookie_store, key: 'cookie_store_key'
  secrets.secret_token    = 'secret_token'
  secrets.secret_key_base = 'secret_key_base'
  config.action_mailer.delivery_method = :test

  config.logger = Logger.new($stdout)
  Rails.logger  = config.logger

  routes.draw do
    get '/' => 'test#index'
  end
end

ActionMailer::Base.delivery_method = :test

class TestMailer < ActionMailer::Base
  def msg
    mail to:"foo@bar.com",
         subject:"asd",
         from: "a@a.com",
         body: "test"
  end
  def msg_and_deliver
    msg.deliver
  end
end

class TestController < ActionController::Base
  include Rails.application.routes.url_helpers

  def index
    render text: 'Home'
  end
end

require 'minitest/autorun'
require 'rack/test'

class BugTest < Minitest::Test
  include Rack::Test::Methods

  def test_msg
    ActionMailer::Base.deliveries.clear
    TestMailer.msg.deliver
    assert_equal 1,ActionMailer::Base.deliveries.size 
  end
 
  def test_msg_and_deliver
    ActionMailer::Base.deliveries.clear
    TestMailer.msg_and_deliver
    assert_equal 1,ActionMailer::Base.deliveries.size 
  end

  def test_msg_and_deliver_with_something_called
    ActionMailer::Base.deliveries.clear
    TestMailer.msg_and_deliver.present?
    assert_equal 1,ActionMailer::Base.deliveries.size 
  end

  private
    def app
      Rails.application
    end
end