Specifying Merb Mailers

9th May 2008 | Tags: programming merb specs

This helper is based on some other controller/view helpers I’ve been working on and planning on blogging soon, with a nod to the specs present in the merb-mailer library itself.

I’m still considering the idea of separate specs for UserMailer and its views, but I think the overhead is too much for mailers, compared to the benefits we get for regular controllers/views. I think this is a result of the way the send_mail helper functions.

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# in a controller
send_mail UserMailer, :hello, {
  :from => "greeter@example.com",
  :to => @person.email,
  :subject => "Greetings"
}, {
  :name => @person.name
}

The controller spec can simply stub/mock the send_mail call as appropriate.

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# spec/spec_helper.rb
Merb::Mailer.delivery_method = :test_send
def describe_mail(mailer, template, &block)
  describe "/#{mailer.to_s.downcase}/#{template}" do
    before :each do
      @mailer_class, @template = mailer, template
      @assigns = {}
    end

    def deliver(send_params={}, mail_params={})
      mail_params = {:from => "from@example.com", :to => "to@example.com", :subject => "Subject Line"}.merge(mail_params)
      @mailer_class.new(send_params).dispatch_and_deliver @template.to_sym, mail_params
      @mail = Merb::Mailer.deliveries.last
    end

    instance_eval &block
  end
end

# spec/mailers/user\_mailer\_spec.rb
require File.join(File.dirname(__FILE__),'..','spec_helper')

describe_mail UserMailer, :hello do
  it "should say hello" do
    deliver :name => "Jamie"
    @mail.text.should == "Hello Jamie"
  end
end

I’m a big fan of custom rspec describers, as above. The fact that before and after blocks are transparently inherited is a huge win over test/unit, where you’d need to explicitly call super.

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# app/mailers/user_mailer.rb
class UserMailer < Merb::MailController
  def hello
    render_mail
  end  
end

# app/mailers/views/user_mailer/hello.text.erb
Hello <%= params[:name] %>