time_logs_controller.rb

  def update(tl)
    time_log = TimeLog.where(:id => tl[:id]).first
    start = Time.parse(tl[:tt_log_date] + " " + tl[:start_time])
    hours = time_string2hour(tl[:spent_time])
    stop = start + hours.hours

    time_log.update_attributes!(:started_on => start, :stopped_at => stop, :comments => tl[:comments])
    flash[:notice] = l(:tt_update_log_success)
  rescue StandardError => e
    flash[:error] = e.message
  end

time_logs_controller_test.rb

      should "update only TL -comments on own logs" do
        post :actions, {:time_log_edit => {1 => {:id => 1, :comments => "new comment", :tt_log_date => "2012-10-25",
                                                :start_time => "11:47:23", :stop_time => "11:53:42",
                                                :spent_time => "6m 19s"}}}
        assert_response 302, "on update TL"
        tl = TimeLog.where(:id => 1).first
        assert_equal("new comment", tl.comments, "updated TL-comment")
      end