rabbit consumer testing

consumer.rb

    class BaseMessageHandler
      def initialize(opts = {})
        @connection_string = opts[:rabbit_mq_host]
        raise ConfigurationError.new('rabbit_mq_host is not specified') unless @connection_string
      end

      def fetch_channel
        AMQP.start(@connection_string) do |connection, open_ok|
          AMQP::Channel.new(connection) do |channel|
            yield channel
            channel.on_error do |ch, close|
              puts "Handling a channel-level exception on channel: #{close.reply_text}, #{close.inspect}"
            end
            connection.close {
              EventMachine.stop { exit }
            }
          end
        end
      rescue AMQP::PossibleAuthenticationFailureError => afe
        afe.settings.delete(:user)
        afe.settings.delete(:pass)
        puts "Authentication failure! AMQP broker closed TCP connection before authentication succeeded #{afe.settings}" #airbrake todo
      rescue AMQP::TCPConnectionFailed => e
        puts "Caught AMQP::TCPConnectionFailed => TCP connection failed, as expected. #{e}"
      end
    end
    
    class Consumer < BaseMessageHandler
      attr_reader :queue_name

      def initialize(opts = {})
        @queue_name = opts[:queue_name]
        raise ConfigurationError.new('queue_name is not specified') unless @queue_name
        super
      end

      def consume
        message = nil
        fetch_channel do |channel|
          pop_message(channel) do |payload|
            message = payload
          end
        end
        message
      end

      private

      def pop_message(channel)
        channel.queue(@queue_name, DURABILITY_OPTS).pop do |metadata, payload|
          yield payload if payload
        end
      end
    end