notifier.rb

class Notifier < ActionMailer::Base
  delivers_from "[email protected]"

  # Subject can be set in your I18n file at config/locales/en.yml
  # with the following lookup:
  #
  #   en.actionmailer.notifier.foo.subject
  #
  def foo
    @greeting = "Hi"
    mail(:to => "")
  end

  # Subject can be set in your I18n file at config/locales/en.yml
  # with the following lookup:
  #
  #   en.actionmailer.notifier.bar.subject
  #
  def bar
    @greeting = "Hi"
    mail(:to => "")
  end
end

notifier_test.rb

require 'test_helper'

class NotifierTest < ActionMailer::TestCase
  test "foo" do
    @actual = Notifier.foo

    @expected.subject = "Foo"
    @expected.from    = "[email protected]"
    @expected.body    = read_fixture("foo")
    @expected.date    = Time.now

    assert_difference "Notifier.deliveries.size" do
      @actual.deliver
    end

    assert_equal @expected.encoded, @actual.encoded
  end

  test "bar" do
    @actual = Notifier.bar

    @expected.subject = "Bar"
    @expected.from    = "[email protected]"
    @expected.body    = read_fixture("bar")
    @expected.date    = Time.now

    assert_difference "Notifier.deliveries.size" do
      @actual.deliver
    end

    assert_equal @expected.encoded, @actual.encoded
  end

end