module ActionMailer::TestHelper

# File actionmailer/lib/action_mailer/test_helper.rb, line 34
def assert_emails(number)
  if block_given?
    original_count = ActionMailer::Base.deliveries.size
    yield
    new_count = ActionMailer::Base.deliveries.size
    assert_equal number, new_count - original_count, "#{number} emails expected, but #{new_count - original_count} were sent"
  else
    assert_equal number, ActionMailer::Base.deliveries.size
  end
end

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_now
  end
end

# File actionmailer/lib/action_mailer/test_helper.rb, line 113
def assert_enqueued_email_with(mailer, method, args: nil, queue: "mailers", &block)
  if args.is_a? Hash
    job = ActionMailer::Parameterized::DeliveryJob
    args = [mailer.to_s, method.to_s, "deliver_now", args]
  else
    job = ActionMailer::DeliveryJob
    args = [mailer.to_s, method.to_s, "deliver_now", *args]
  end

  assert_enqueued_with(job: job, args: args, queue: queue, &block)
end

Asserts 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: '[email protected]} do
    ContactMailer.with(email: '[email protected]').welcome.deliver_later
  end
end

# File actionmailer/lib/action_mailer/test_helper.rb, line 92
def assert_enqueued_emails(number, &block)
  assert_enqueued_jobs number, only: [ ActionMailer::DeliveryJob, ActionMailer::Parameterized::DeliveryJob ], &block
end

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

# File actionmailer/lib/action_mailer/test_helper.rb, line 64
def assert_no_emails(&block)
  assert_emails 0, &block
end

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

# File actionmailer/lib/action_mailer/test_helper.rb, line 140
def assert_no_enqueued_emails(&block)
  assert_no_enqueued_jobs only: [ ActionMailer::DeliveryJob, ActionMailer::Parameterized::DeliveryJob ], &block
end

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