create_email_test_operation.rb

class CreateEmailTest
  include Lotus::Interactor

  def initialize(params)
    @params = params
    @email_test  = EmailTest.new(@params[:email_test])
  end

  def call
    Operation.new(self, email_test: @email_test).
      then(:validate).
      then(:persist).
      then(:capture_screenshot).
      then(:deliver_emails).run
  end

  private
  def validate
    errors @params.errors unless @params.valid?
  end

  def persist
     EmailTestRepository.create(@email_test)
  end

  def capture_screenshot
     Screenshot.new(@email_test).capture
  rescue
     error "There was a problem while capturing the screenshot"
  end

  def deliver_emails
     # ...
  end
end

create_email_test_throw.rb

class CreateEmailTest
  include Lotus::Interactor

  def initialize(params)
    @params = params
    @email_test  = EmailTest.new(@params[:email_test])
  end

  # List the operations to execute.
  # Once error/errors is called, it uses `throw` to interrupt the flow.
  #
  # It has an implicit return value:
  # Result
  #  email_test (how to declare its inclusion?)
  #  errors
  #  success?

  def call
    validate
    persist
    capture_screenshot
    deliver_emails
  end

  private
  def validate
    errors @params.errors unless @params.valid?
  end

  def persist
    @email_test = EmailTestRepository.create(@email_test)
    error "Not persisted" if @email_test.id.nil?
  end

  def capture_screenshot
     Screenshot.new(@email_test).capture
  rescue
     error "There was a problem while capturing the screenshot"
  end

  def deliver_emails
    # ...
  end
end