# File lib/fog/aws/requests/iam/add_user_to_group.rb, line 35
        def add_user_to_group(group_name, user_name)
          if data[:groups].has_key? group_name
            if data[:users].has_key? user_name

              unless data[:groups][group_name][:members].include?(user_name)
                data[:groups][group_name][:members] << user_name
              end

              Excon::Response.new.tap do |response|
                response.status = 200
                response.body = { 'RequestId' => Fog::AWS::Mock.request_id }
              end
            else
              raise Fog::AWS::IAM::NotFound.new("The user with name #{user_name} cannot be found.")
            end
          else
            raise Fog::AWS::IAM::NotFound.new("The group with name #{group_name} cannot be found.")
          end
        end