module ActionMailer::TestHelper

end
end
ContactMailer.welcome.deliver_later
ContactMailer.welcome.deliver_now
assert_emails 2 do

end
ContactMailer.welcome.deliver_now
assert_emails 1 do
def test_emails_again

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

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

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

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

end
end
ContactMailer.with(email: 'user@example.com').welcome.deliver_later
args: {email: 'user@example.com'} do
assert_enqueued_email_with ContactMailer, :welcome,
def test_parameterized_email

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

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

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

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

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

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

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

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

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

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

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

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

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
  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

end
end
ContactMailer.welcome.deliver_later
ContactMailer.welcome.deliver_later
assert_enqueued_emails 2 do

end
ContactMailer.welcome.deliver_later
assert_enqueued_emails 1 do
def test_emails_again

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

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

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

def assert_enqueued_emails(number, &block)
  assert_enqueued_jobs(number, only: ->(job) { delivery_job_filter(job) }, &block)
end

assert_emails 0, &block

Note: This assertion is simply a shortcut for:

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

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

end
assert_emails 1
ContactMailer.welcome.deliver_now
assert_no_emails
def test_emails

Asserts that no emails have been sent.

def assert_no_emails(&block)
  assert_emails 0, &block
end

end
end
# No emails should be enqueued from this block
assert_no_enqueued_emails do
def test_no_emails

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

end
assert_enqueued_emails 1
ContactMailer.welcome.deliver_later
assert_no_enqueued_emails
def test_no_emails

Asserts that no emails are enqueued for later delivery.

def assert_no_enqueued_emails(&block)
  assert_enqueued_emails 0, &block
end

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

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

Returns any emails that are sent in the block.

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

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

end
assert_emails 1

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

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

end
assert_emails 1

deliver_enqueued_emails

ContactMailer.welcome.deliver_later
def test_deliver_enqueued_emails_without_block

end
assert_emails 1

end
ContactMailer.welcome.deliver_later
deliver_enqueued_emails do
def test_deliver_enqueued_emails

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

def deliver_enqueued_emails(queue: nil, at: nil, &block)
  perform_enqueued_jobs(only: ->(job) { delivery_job_filter(job) }, queue: queue, at: at, &block)
end

def delivery_job_filter(job)
  job_class = job.is_a?(Hash) ? job.fetch(:job) : job.class
  Base.descendants.map(&:delivery_job).include?(job_class)
end