sms_notices_controller.rb

class SmsNoticesController < ApplicationController
  def create
    listing = Listing.find(params[:listing_id])
    sms = Sms.new(listing.name, params[:phone_number])
    if sms.deliver
      flash[:notice] = "SMS sent successfully."
    else
      flash[:alert] = "Something went wrong. Please try sending SMS again."
    end 

    respond_to do |format|
      format.html { redirect_to(listing_url(listing)) }
    end 
  end 
end

sms_notices_controller_spec.rb

require 'spec_helper'

describe SmsNoticesController do
  describe "SMS sending" do
    before(:each) do
      @listing = mock_model(Listing, :name => "Google")
    end

    describe "#create" do
      before(:each) do
        Listing.stub!(:find).with(@listing.id).and_return(@listing)
        @sms = mock(Sms) # non databse backed model
      end

      it 'should send sms and inform user' do
        controller.should_receive(:simple_captcha_valid?).and_return(true)
        @sms.should_receive(:deliver).and_return(true)

        post :create, :listing_id => @listing.id
        flash[:notice].should == "SMS sent successfully."
        response.should redirect_to(listing_url(@listing))
      end

    end
  end
end