module ActionMailer::TestHelper

# File actionmailer/lib/action_mailer/test_helper.rb, line 32
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 90
def assert_enqueued_emails(number, &block)
  assert_enqueued_jobs number, only: ActionMailer::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 62
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

# File actionmailer/lib/action_mailer/test_helper.rb, line 109
def assert_no_enqueued_emails(&block)
  assert_no_enqueued_jobs only: ActionMailer::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