Provides helper methods for testing Action Mailer, including assert_emails and assert_no_emails.

Methods

Included Modules

Instance Public methods

assert_emails(number, &block)

Asserts that the number of emails sent matches the given number.

def test_emails
  assert_emails 0
  ContactMailer.welcome.deliver_now
  assert_emails 1
  ContactMailer.welcome.deliver_now
  assert_emails 2
end

If a block is passed, that block should cause the specified number of emails to be sent.

def test_emails_again
  assert_emails 1 do
    ContactMailer.welcome.deliver_now
  end

  assert_emails 2 do
    ContactMailer.welcome.deliver_now
    ContactMailer.welcome.deliver_later
  end
end
📝 Source code 
# File actionmailer/lib/action_mailer/test_helper.rb, line 35
    def assert_emails(number, &block)
      if block_given?
        diff = capture_emails(&block).length
        assert_equal number, diff, "#{number} emails expected, but #{diff} were sent"
      else
        assert_equal number, ActionMailer::Base.deliveries.size
      end
    end
🔎 See on GitHub

assert_enqueued_email_with(mailer, method, params: nil, args: nil, queue: nil, &block)

Asserts that a specific email has been enqueued, optionally matching arguments and/or params.

def test_email
  ContactMailer.welcome.deliver_later
  assert_enqueued_email_with ContactMailer, :welcome
end

def test_email_with_parameters
  ContactMailer.with(greeting: "Hello").welcome.deliver_later
  assert_enqueued_email_with ContactMailer, :welcome, args: { greeting: "Hello" }
end

def test_email_with_arguments
  ContactMailer.welcome("Hello", "Goodbye").deliver_later
  assert_enqueued_email_with ContactMailer, :welcome, args: ["Hello", "Goodbye"]
end

def test_email_with_named_arguments
  ContactMailer.welcome(greeting: "Hello", farewell: "Goodbye").deliver_later
  assert_enqueued_email_with ContactMailer, :welcome, args: [{ greeting: "Hello", farewell: "Goodbye" }]
end

def test_email_with_parameters_and_arguments
  ContactMailer.with(greeting: "Hello").welcome("Cheers", "Goodbye").deliver_later
  assert_enqueued_email_with ContactMailer, :welcome, params: { greeting: "Hello" }, args: ["Cheers", "Goodbye"]
end

def test_email_with_parameters_and_named_arguments
  ContactMailer.with(greeting: "Hello").welcome(farewell: "Goodbye").deliver_later
  assert_enqueued_email_with ContactMailer, :welcome, params: { greeting: "Hello" }, args: [{farewell: "Goodbye"}]
end

def test_email_with_parameterized_mailer
  ContactMailer.with(greeting: "Hello").welcome.deliver_later
  assert_enqueued_email_with ContactMailer.with(greeting: "Hello"), :welcome
end

def test_email_with_matchers
  ContactMailer.with(greeting: "Hello").welcome("Cheers", "Goodbye").deliver_later
  assert_enqueued_email_with ContactMailer, :welcome,
    params: ->(params) { /hello/i.match?(params[:greeting]) },
    args: ->(args) { /cheers/i.match?(args[0]) }
end

If a block is passed, that block should cause the specified email to be enqueued.

def test_email_in_block
  assert_enqueued_email_with ContactMailer, :welcome do
    ContactMailer.welcome.deliver_later
  end
end

If args is provided as a Hash, a parameterized email is matched.

def test_parameterized_email
  assert_enqueued_email_with ContactMailer, :welcome,
    args: {email: 'user@example.com'} do
    ContactMailer.with(email: 'user@example.com').welcome.deliver_later
  end
end
📝 Source code 
# File actionmailer/lib/action_mailer/test_helper.rb, line 157
    def assert_enqueued_email_with(mailer, method, params: nil, args: nil, queue: nil, &block)
      if mailer.is_a? ActionMailer::Parameterized::Mailer
        params = mailer.instance_variable_get(:@params)
        mailer = mailer.instance_variable_get(:@mailer)
      end

      if args.is_a?(Hash)
        ActionMailer.deprecator.warn <<~MSG
          Passing a Hash to the assert_enqueued_email_with :args kwarg causes the
          Hash to be treated as params. This behavior is deprecated and will be
          removed in Rails 7.2.

          To specify a params Hash, use the :params kwarg:

            assert_enqueued_email_with MyMailer, :my_method, params: { my_param: "value" }

          Or, to specify named mailer args as a Hash, wrap the Hash in an array:

            assert_enqueued_email_with MyMailer, :my_method, args: [{ my_arg: "value" }]
            # OR
            assert_enqueued_email_with MyMailer, :my_method, args: [my_arg: "value"]
        MSG

        params, args = args, nil
      end

      args = Array(args) unless args.is_a?(Proc)
      queue ||= mailer.deliver_later_queue_name || ActiveJob::Base.default_queue_name

      expected = ->(job_args) do
        job_kwargs = job_args.extract_options!

        [mailer.to_s, method.to_s, "deliver_now"] == job_args &&
          params === job_kwargs[:params] && args === job_kwargs[:args]
      end

      assert_enqueued_with(job: mailer.delivery_job, args: expected, queue: queue.to_s, &block)
    end
🔎 See on GitHub

assert_enqueued_emails(number, &block)

Asserts that the number of emails enqueued for later delivery matches the given number.

def test_emails
  assert_enqueued_emails 0
  ContactMailer.welcome.deliver_later
  assert_enqueued_emails 1
  ContactMailer.welcome.deliver_later
  assert_enqueued_emails 2
end

If a block is passed, that block should cause the specified number of emails to be enqueued.

def test_emails_again
  assert_enqueued_emails 1 do
    ContactMailer.welcome.deliver_later
  end

  assert_enqueued_emails 2 do
    ContactMailer.welcome.deliver_later
    ContactMailer.welcome.deliver_later
  end
end
📝 Source code 
# File actionmailer/lib/action_mailer/test_helper.rb, line 91
    def assert_enqueued_emails(number, &block)
      assert_enqueued_jobs(number, only: ->(job) { delivery_job_filter(job) }, &block)
    end
🔎 See on GitHub

assert_no_emails(&block)

Asserts that no emails have been sent.

def test_emails
  assert_no_emails
  ContactMailer.welcome.deliver_now
  assert_emails 1
end

If a block is passed, that block should not cause any emails to be sent.

def test_emails_again
  assert_no_emails do
    # No emails should be sent from this block
  end
end

Note: This assertion is simply a shortcut for:

assert_emails 0, &block
📝 Source code 
# File actionmailer/lib/action_mailer/test_helper.rb, line 63
    def assert_no_emails(&block)
      assert_emails 0, &block
    end
🔎 See on GitHub

assert_no_enqueued_emails(&block)

Asserts that no emails are enqueued for later delivery.

def test_no_emails
  assert_no_enqueued_emails
  ContactMailer.welcome.deliver_later
  assert_enqueued_emails 1
end

If a block is provided, it should not cause any emails to be enqueued.

def test_no_emails
  assert_no_enqueued_emails do
    # No emails should be enqueued from this block
  end
end
📝 Source code 
# File actionmailer/lib/action_mailer/test_helper.rb, line 211
    def assert_no_enqueued_emails(&block)
      assert_enqueued_emails 0, &block
    end
🔎 See on GitHub

capture_emails(&block)

Returns any emails that are sent in the block.

def test_emails
  emails = capture_emails do
    ContactMailer.welcome.deliver_now
  end
  assert_equal "Hi there", emails.first.subject

  emails = capture_emails do
    ContactMailer.welcome.deliver_now
    ContactMailer.welcome.deliver_later
  end
  assert_equal "Hi there", emails.first.subject
end
📝 Source code 
# File actionmailer/lib/action_mailer/test_helper.rb, line 269
    def capture_emails(&block)
      original_count = ActionMailer::Base.deliveries.size
      deliver_enqueued_emails(&block)
      new_count = ActionMailer::Base.deliveries.size
      diff = new_count - original_count
      ActionMailer::Base.deliveries.last(diff)
    end
🔎 See on GitHub

deliver_enqueued_emails(queue: nil, at: nil, &block)

Delivers all enqueued emails. If a block is given, delivers all of the emails that were enqueued throughout the duration of the block. If a block is not given, delivers all the enqueued emails up to this point in the test.

def test_deliver_enqueued_emails
  deliver_enqueued_emails do
    ContactMailer.welcome.deliver_later
  end

  assert_emails 1
end

def test_deliver_enqueued_emails_without_block
  ContactMailer.welcome.deliver_later

  deliver_enqueued_emails

  assert_emails 1
end

If the :queue option is specified, then only the emails(s) enqueued to a specific queue will be performed.

def test_deliver_enqueued_emails_with_queue
  deliver_enqueued_emails queue: :external_mailers do
    CustomerMailer.deliver_later_queue_name = :external_mailers
    CustomerMailer.welcome.deliver_later # will be performed
    EmployeeMailer.deliver_later_queue_name = :internal_mailers
    EmployeeMailer.welcome.deliver_later # will not be performed
  end

  assert_emails 1
end

If the :at option is specified, then only delivers emails enqueued to deliver immediately or before the given time.

📝 Source code 
# File actionmailer/lib/action_mailer/test_helper.rb, line 251
    def deliver_enqueued_emails(queue: nil, at: nil, &block)
      perform_enqueued_jobs(only: ->(job) { delivery_job_filter(job) }, queue: queue, at: at, &block)
    end
🔎 See on GitHub