pony.rb

def self.transport_via_smtp(tmail, options={})
    o = options[:smtp] || {}
    smtp = Net::SMTP.new(o[:host], o[:port])
    smtp.start(o[:domain], o[:user], o[:password], o[:auth])
    smtp.send_message tmail.to_s, tmail.from, tmail.to
    smtp.finish
  end

pony_spec.rb

require File.dirname(__FILE__) + '/base'

describe Pony do
  
  describe "transport" do
    
    it "transports mail via Net::SMTP using specified server" do
      o = {:smtp => {:host => 'localhost', :port => '25', :domain => 'localhost.localdomain', :user => 'user', :password => 'password', :auth => 'plain'}}
      smtp = mock('net::smtp object')
      Net::SMTP.should_receive(:new).with('localhost', '25').and_return(smtp)
      smtp.should_receive(:start).with('localhost.localdomain', 'user', 'password', 'plain')
      smtp.should_receive(:send_message).with('message', 'from', 'to')
      smtp.should_receive(:finish)
      Pony.transport_via_smtp(mock('tmail', :to => 'to', :from => 'from', :to_s => 'message'), o)
    end
  end

end