Issues with Shoulda and domain model unit tests.

have_sent_email.rb

require 'test_helper'

class GF::Appointments::FooTest < ActiveSupport::TestCase
  # In non-ActiveRecord classes that use Shoulda a subject must be 
  # defined to use the should dsl method.  Otherwise it will try to 
  # instantiate a class based on the class name of the test, in this
  # case it tries to instantiate GF::Appointments::Foo.  This instantiation
  # fails if the initializer has required parameters and may have other
  # undesirable side effects.
  subject { Object.new }

  context "This test" do
    setup do
      # The following clears out the sent emails queue and must be done
      # in the setup of tests that check for emails.
      ActionMailer::Base.deliveries = []

      # Do something that sends an email...
    end

    # This always passes because have_sent_email returns a 
    # Shoulda matcher like the following which is truthy...
    #
    # puts have_sent_email.inspect
    # <Shoulda::Matchers::ActionMailer::HaveSentEmailMatcher:0x10b96cd58 ... >    
    should "send an email" do
      assert have_sent_email("for advisor").
        to("[email protected]").
        with_subject(/Appointment Cancelled/)
    end

    # This may raise an exception unless the subject is set as demonstrated above.
    should have_sent_email("for advisor").
      to("[email protected]").
      with_subject(/Appointment Cancelled/)

  end
end