This is put into your cucumber env.rb file to collect all messages sent through Moonshado in an array that you can check later in your scenario.

moonshado_env.rb

module Moonshado
  class Sms
    cattr_accessor :sent_messages
    
    def deliver_sms
      raise MoonshadoSMSException.new("Invalid message") unless is_message_valid?(@message)

      data = {:sms => {:device_address => format_number(@number), :message => @message.to_s}}

      self.class.sent_messages ||= []
      self.class.sent_messages << data
      response = RestClient::Response.create('{"stat":"ok","id":"sms_id_mock"}', "", {})

      parse(response.to_s)
    rescue MoonshadoSMSException => exception
      raise exception
    end
  end
end

sms_steps.rb

When /^the sms message "([^"]*)" is sent to "([^"]*)"$/ do |number, message|
  Moonshado::Sms.new(message,number).deliver_sms
end

Then /^there should be an SMS sent to "([^"]*)" saying "([^"]*)"$/ do |number, sms_text|
  messages = Moonshado::Sms.sent_messages
  messages = Moonshado::Sms.sent_messages.select{|data| 
    data[:sms][:device_address] == number and data[:sms][:message] == sms_text
  }
  messages.size.should == 1
  messages.each{|msg| Moonshado::Sms.sent_messages.delete(msg)}
end

Then /^there should be no SMS messages sent$/ do 
  if Moonshado::Sms.sent_messages
    Moonshado::Sms.sent_messages.size.should == 0
  end
end