Making ActionMailer testable

If you ever create a custom subclass of ActionMailer you'll be having a hard time to test it. That's because - by default - you cannot access the ActionMailer instance after creating a mail. To make ActionMailer testable you have to make its new-method public:

    1 class ActionMailer::Localized < ActionMailer::Base
    2   
    3   #to make ActionMailer testable
    4   public_class_method :new
    5   
    6   private
    7 
    8   #we would like to test that the correct template is set
    9   def initialize_defaults(method_name)
   10     super
   11     @template = "#{I18n.locale}_#{method_name}"
   12   end
   13   
   14 end

With that change it's easy to test the initialize_defaults-method (as shown here using rspec):

    1 describe ActionMailer::Localized do
    2   
    3   before(:each) do
    4     @localized_mailer = Class.new(ActionMailer::Localized) do
    5       def mailer_method(mail_object); end
    6     end.new
    7     @localized_mailer.stub!(:render)
    8     I18n.locale = 'de'
    9   end
   10 
   11   describe 'after being initialized' do
   12     before(:each) do
   13       @localized_mailer.create!('mailer_method', Object.new)
   14     end
   15     it "should have the localized template name set" do
   16       @localized_mailer.template.should == 'de_mailer_method'
   17     end
   18   end
   19   
   20 end