Fast tests for your mailers in Rails

gistfile1.rb

# test/unit/mailers/my_mailer_test.rb

require 'minitest/spec'
require 'minitest/autorun'
require "minitest-matchers"
require 'action_mailer'
require "email_spec"

# IF WE'VE ALREADY LOADED RAILS, 
# WE DON'T HAVE TO WORRY ABOUT HAML OR MAILER CONFIG
unless Object.const_defined? 'Rails'
  # ONLY NECESSARY TO RECOGNIZE HAML TEMPLATES
  # IF YOU ONLY USE ERB, YOU CAN OMIT THIS
  require 'haml/util'
  require 'haml/template/options'
  require 'haml/engine'
  require 'haml/helpers/action_view_extensions'
  require "haml/template/plugin"
  # END HAML SUPPORT STUFF

  ActionMailer::Base.delivery_method = :test
  ActionMailer::Base.view_paths = File.expand_path('../../../../app/views', __FILE__)
end

require File.expand_path('../../../../app/mailers/my_mailer', __FILE__)

describe MyMailer do
  include EmailSpec::Helpers
  include EmailSpec::Matchers

  let(:the_email){ MyMailer.some_mail() }

  it "has the right bit of text" do
    the_email.must have_body_text("some bit of text")
  end
end