describe EmailSender do
  setup do
    @expected = TMail::Mail.new
    @expected.set_content_type 'text', 'plain', { 'charset' => "utf-8" }
    @expected.mime_version = '1.0'
  end

  it 'should create an email' do
    @expected.subject = 'Rspec'
    @expected.body    = 'Rspec is so cool.'
    @expected.from    = 'myemail@myemail.com'
    @expected.to      = 'youremail@youremail.com'

    EmailSender.create_your_email.encoded.should == @expected.encoded
  end
end

describe YourController do
  it "should send email" do
    EmailSender.should_receive(:deliver_your_email)
    post :your_action
  end
end