Rails - How do you test ActionMailer sent a specific email in tests

Question

Currently in my tests I do something like this to test if an email is queued to be sent

    assert_difference('ActionMailer::Base.deliveries.size', 1) do       
        get :create_from_spreedly, {:user_id => @logged_in_user.id}
    end

but if i a controller action can send two different emails i.e. one to the user if sign up goes fine or a notification to admin if something went wrong - how can i test which one actually got sent. The code above would pass regardless.

Answer 1

When using the ActionMailer during tests, all mails are put in a big array called deliveries. What you basically are doing (and is sufficient mostly) is checking if emails are present in the array. But if you want to specifically check for a certain email, you have to know what is actually stored in the array. Luckily the emails themselves are stored, thus you are able to iterate through the array and check each email.

See ActionMailer::Base to see what configuration methods are available, which you can use to determine what emails are present in the array. Some of the most suitable methods for your case probably are

• recipients: Takes one or more email addresses. These addresses are where your email will be delivered to. Sets the To: header.
• subject: The subject of your email. Sets the Subject: header.

Answer 2

The test framework shoulda has an excellent helper which lets you assert certain conditions about an email that was sent. Yes, you could do it yourself with ActionMailer.deliveries, but shoulda makes it all one neat little block

Answer 3

Here is the best way I've found to do it.

1) Include the action mailer callbacks plugin like this:

script/plugin install git://github.com/AnthonyCaliendo/action_mailer_callbacks.git

I don't really use the plugin's main features, but it does provide the nice functionality of being able to figure out which method was used to send an email.

2) Now you can put some methods in your test_helper.rb like this:

  def assert_sent(method_name)
    assert sent_num_times(method_name) > 0
  end

  def assert_not_sent(method_name)
    assert sent_num_times(method_name) == 0
  end

  def assert_sent_once(method_name)
    assert sent_num_times(method_name) == 1
  end

  def sent_num_times(method_name)
    count = 0
    @emails.each do |email|
      count += 1 if method_name == email.instance_variable_get("@method_name")
    end
    count
  end

3) Now you can write sweet tests like this:

require 'test_helper'
class MailingTest < ActionController::IntegrationTest

  def setup
    @emails = ActionMailer::Base.deliveries
    @emails.clear
  end

  test "should send a mailing" do
    assert_difference "Mailing.count", 1 do
      feeds(:feed1).generate_mailing
    end

    assert_sent_once "broadcast"
    assert_not_sent "failed_mailing"
  end
end

Here "broadcast" and "mailing_failed" are the names of the methods in my ActionMailer::Base class. These are the ones you normally use by calling Mailer.deliver_broadcast(some_data) or Mailer.deliver_failed_mailing(some_data) etc. That's it!

Answer 4

As of rails 3 ActionMailer::Base.deliveries is an array of Mail::Message's. From the mail documentation:

#  mail['from'] = '[email protected]'
#  mail[:to]    = '[email protected]'
#  mail.subject 'This is a test email'
#  mail.body    = 'This is a body'
# 
#  mail.to_s #=> "From: [email protected]\r\nTo: you@...

From that it should be easy to test your mail's in an integration

mail = ActionMailer::Base.deliveries.last

assert_equal '[email protected]', mail['from'].to_s

assert_equal '[email protected]', mail['to'].to_s