    # File lib/fog/aws/requests/iam/list_groups_for_user.rb, line 43
            def list_groups_for_user(user_name, options = {})
              #FIXME: Does not consider options
              if data[:users].has_key? user_name
                Excon::Response.new.tap do |response|
                  response.status = 200
                  response.body = { 'GroupsForUser' => data[:groups].select do |name, group|
                                                         group[:members].include? user_name
                                                       end.map do |name, group|
                                                         { 'GroupId'   => group[:group_id],
                                                           'GroupName' => name,
                                                           'Path'      => group[:path],
                                                           'Arn'       => (group[:arn]).strip }
                                                       end,
                                    'IsTruncated' => false,
                                    'RequestId' => Fog::AWS::Mock.request_id
                                  }
                end
              else
                raise Fog::AWS::IAM::NotFound.new("The user with name #{user_name} cannot be found.")
              end
            end