gistfile1.rb

begin
  require 'bundler/inline'
rescue LoadError => e
  $stderr.puts 'Bundler version 1.10 or later is required. Please update your Bundler'
  raise e
end

gemfile(true) do
  source 'https://rubygems.org'
  gem 'rails', github: 'rails/rails'
  gem 'arel', github: 'rails/arel'
  gem 'rack', github: 'rack/rack'
  gem 'sprockets', github: 'rails/sprockets'
  gem 'sprockets-rails', github: 'rails/sprockets-rails'
  gem 'sass-rails', github: 'rails/sass-rails'
end

require 'action_mailer'
require 'active_support'
require 'active_support/core_ext/object/blank'
require 'active_support/test_case'
require 'minitest/autorun'

# Ensure backward compatibility with Minitest 4
Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)

class SimpleMailer < ActionMailer::Base
  include ActionView::Helpers::AssetTagHelper

  def welcome
    attachments.inline['an image.jpg'] = File.read('/tmp/8122246.jpeg')
    mail(to: 'john@example.com', subject: "test") do |format|
      format.html { render html: image_tag(attachments['an image.jpg'].url) }
    end
  end
end

class BugTest < ActiveSupport::TestCase
  def test_stuff
    assert_nothing_raised do
      SimpleMailer.welcome
    end
  end
end