municipalities_controller.rb

class Api::V2::MunicipalitiesController < Api::V2::BaseController

  def index
    municipalities = Municipality.find_all_for_api

    @municipalities = municipalities.collect { |m| {:id => m.id, :name => m.name} }

    render_json(@municipalities)
  end
end

municipalities_controller_spec.rb

require 'spec_helper'

describe Api::V2::MunicipalitiesController do

  let(:api_key) { mock_model(ApiKey, :key => "123") }
  let(:municipality) { mock_model(Municipality, :name => "Munun.. 1") }

  describe "GET 'index'" do

    context "no municipalities" do

      it "returns empty json" do
        Municipality.should_receive(:find_all_for_api).and_return([])

        get :index, :format => 'json', :api_key => api_key.key

        response.body.should == '[]'
      end

    end

    context "two municipalities" do

      it "returns json with names" do
        Municipality.should_receive(:find_all_for_api).and_return([municipality])

        get :index, :format => 'json', :api_key => api_key.key

        expected_response = %([{"name":"#{municipality.name}","id":#{municipality.id}}]')

        response.body.should == expected_response
      end

    end

  end

end