From a45e537bac0d9eba0516d867a8ce40dec890dc1b Mon Sep 17 00:00:00 2001
From: Nishanth Vijayan <nishanththegr8@gmail.com>
Date: Tue, 24 May 2016 23:54:46 +0530
Subject: [PATCH 1/3] Setup basic Revision History page

Sets up paper_trail tracking in important models

and add conference_id to versions for storing conference_id
of conference related objects  as metadata.This will help in querying
for versions related to conferences.

Fix issues with factories & event types initialization.Import paper_trail testing helpers
Fix bug: Creating an event creates a useless version with event update

Add revert and view changes features to revision history
---
 app/assets/javascripts/application.js         |   1 +
 app/assets/javascripts/osem-datatables.js     |   5 +
 .../javascripts/osem-revisionhistory.js       |  10 ++
 app/assets/stylesheets/osem.css.scss          |   4 +
 app/controllers/admin/versions_controller.rb  |  58 +++++++
 app/helpers/application_helper.rb             | 121 ++++++++++++++
 app/models/ability.rb                         |  12 ++
 app/models/campaign.rb                        |   2 +
 app/models/cfp.rb                             |   5 +
 app/models/comment.rb                         |   6 +
 app/models/commercial.rb                      |  10 ++
 app/models/conference.rb                      |   2 +-
 app/models/contact.rb                         |   2 +
 app/models/difficulty_level.rb                |   7 +
 app/models/email_settings.rb                  |   2 +
 app/models/event.rb                           |  10 +-
 app/models/event_type.rb                      |   6 +
 app/models/events_registration.rb             |   8 +
 app/models/lodging.rb                         |   2 +
 app/models/program.rb                         |  36 ++--
 app/models/registration.rb                    |   8 +-
 app/models/registration_period.rb             |   2 +
 app/models/role.rb                            |   6 +-
 app/models/room.rb                            |   6 +
 app/models/splashpage.rb                      |   2 +
 app/models/sponsor.rb                         |   2 +
 app/models/sponsorship_level.rb               |   2 +
 app/models/subscription.rb                    |   2 +
 app/models/target.rb                          |   2 +
 app/models/ticket.rb                          |   2 +
 app/models/track.rb                           |   6 +
 app/models/user.rb                            |   8 +-
 app/models/users_role.rb                      |  12 ++
 app/models/venue.rb                           |   2 +
 app/models/vote.rb                            |   9 +
 .../admin/versions/_object_changes.html.haml  |  28 ++++
 .../versions/_object_desc_and_link.html.haml  | 158 ++++++++++++++++++
 app/views/admin/versions/index.html.haml      |  77 +++++++++
 .../layouts/_admin_sidebar_index.html.haml    |   5 +
 app/views/layouts/_user_menu.html.haml        |   5 +
 config/routes.rb                              |   4 +
 ...524050538_add_conference_id_to_versions.rb |   5 +
 .../20160614145614_add_id_to_users_roles.rb   |   5 +
 db/schema.rb                                  |   3 +-
 .../admin/versions_controller_spec.rb         | 101 +++++++++++
 spec/factories/events.rb                      |   1 -
 spec/factories/tracks.rb                      |   1 +
 spec/features/ability_spec.rb                 |   9 +
 spec/spec_helper.rb                           |   4 +
 49 files changed, 760 insertions(+), 26 deletions(-)
 create mode 100644 app/assets/javascripts/osem-revisionhistory.js
 create mode 100644 app/controllers/admin/versions_controller.rb
 create mode 100644 app/models/users_role.rb
 create mode 100644 app/views/admin/versions/_object_changes.html.haml
 create mode 100644 app/views/admin/versions/_object_desc_and_link.html.haml
 create mode 100644 app/views/admin/versions/index.html.haml
 create mode 100644 db/migrate/20160524050538_add_conference_id_to_versions.rb
 create mode 100644 db/migrate/20160614145614_add_id_to_users_roles.rb
 create mode 100644 spec/controllers/admin/versions_controller_spec.rb

diff --git a/app/assets/javascripts/application.js b/app/assets/javascripts/application.js
index f6322490..8853d6e6 100644
--- a/app/assets/javascripts/application.js
+++ b/app/assets/javascripts/application.js
@@ -41,6 +41,7 @@
 //= require osem-schedule
 //= require osem-switch
 //= require osem-bootstrap
+//= require osem-revisionhistory
 //= require osem-commercials
 //= require unobtrusive_flash
 //= require unobtrusive_flash_bootstrap
diff --git a/app/assets/javascripts/osem-datatables.js b/app/assets/javascripts/osem-datatables.js
index c2b3b75e..f950159e 100644
--- a/app/assets/javascripts/osem-datatables.js
+++ b/app/assets/javascripts/osem-datatables.js
@@ -7,6 +7,11 @@ $(function () {
       pagingType: 'full_numbers',
       "lengthMenu": [[25, 50, 100, -1], [25, 50, 100, "All"]]
     });
+
+    $('#versionstable').DataTable({
+      pagingType: 'full_numbers',
+      order: [[ 0, 'desc' ]]
+    });
   });
 });
 
diff --git a/app/assets/javascripts/osem-revisionhistory.js b/app/assets/javascripts/osem-revisionhistory.js
new file mode 100644
index 00000000..bd51435b
--- /dev/null
+++ b/app/assets/javascripts/osem-revisionhistory.js
@@ -0,0 +1,10 @@
+$(document).ready(function() {
+    $('.show-changeset').click(function(){
+        if ($(this).text() == 'View Changes'){
+            $(this).text('Hide Changes');
+        }else {
+            $(this).text('View Changes');
+        }
+        $('#changeset-' + this.id).toggle();
+    });
+});
diff --git a/app/assets/stylesheets/osem.css.scss b/app/assets/stylesheets/osem.css.scss
index ccd96331..d2a2cd10 100644
--- a/app/assets/stylesheets/osem.css.scss
+++ b/app/assets/stylesheets/osem.css.scss
@@ -86,3 +86,7 @@ p.comment-body {
 #proposal-info div dt, #proposal-info div dd {
   display: inline-block;
 }
+
+.changeset{
+  display: none;
+}
diff --git a/app/controllers/admin/versions_controller.rb b/app/controllers/admin/versions_controller.rb
new file mode 100644
index 00000000..d103e874
--- /dev/null
+++ b/app/controllers/admin/versions_controller.rb
@@ -0,0 +1,58 @@
+module Admin
+  class VersionsController < Admin::BaseController
+    skip_authorization_check
+
+    def index
+      authorize! :index, PaperTrail::Version.new(item_type: 'User')
+      conf_ids_for_organizer = current_user.is_admin? ? Conference.pluck(:id) : Conference.with_role(:organizer, current_user).pluck(:id)
+      @versions = PaperTrail::Version.where(["conference_id IN (?) OR item_type = 'User'", conf_ids_for_organizer])
+    end
+
+    def revert_attribute
+      @version = PaperTrail::Version.find(params[:id])
+      authorize! :revert_attribute, @version
+
+      if params[:attribute] && @version.changeset.reject{ |_, values| values[0].blank? && values[1].blank? }.keys.include?(params[:attribute])
+        if @version.item[params[:attribute]] == @version.changeset[params[:attribute]][0]
+          flash[:error] = 'The item is already in the state that you are trying to revert it back to'
+
+        else
+          @version.item[params[:attribute]] = @version.changeset[params[:attribute]][0]
+          if @version.item.save
+            flash[:notice] = 'The selected change was successfully reverted'
+          else
+            flash[:error] = "An error prohibited this change from being reverted: #{@version.item.errors.full_messages.join('. ')}."
+          end
+        end
+
+      else
+        flash[:error] = 'Revert failed. Attribute missing or invalid'
+      end
+
+      redirect_to admin_revision_history_path
+    end
+
+    def revert_object
+      @version = PaperTrail::Version.find(params[:id])
+      authorize! :revert_object, @version
+
+      if @version.event != 'create'
+        if @version.reify.save
+          flash[:notice] = 'The selected change was successfully reverted'
+        else
+          flash[:error] = "An error prohibited this change from being reverted: #{@version.reify.errors.full_messages.join('. ')}."
+        end
+
+      elsif @version.event == 'create' && @version.item
+        # if @version represets a create event and is not currently deleted
+        @version.item.destroy
+        flash[:notice] = 'The selected change was successfully reverted'
+
+      else
+        flash[:error] = 'The item is already in the state that you are trying to revert it back to'
+      end
+
+      redirect_to admin_revision_history_path
+    end
+  end
+end
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 8283150a..09f69484 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -370,4 +370,125 @@ module ApplicationHelper
   def selected_scheduled?(schedule)
     (schedule == @selected_schedule) ? 'Yes' : 'No'
   end
+
+  # Recieves a PaperTrail::Version object
+  # Outputs the list of attributes that were changed in the version (ignoring changes from one blank value to another)
+  # Eg: If version.changeset = '{"title"=>[nil, "Premium"], "description"=>[nil, "Premium = Super cool"], "conference_id"=>[nil, 3]}'
+  # Output will be 'title, description and conference'
+  def updated_attributes(version)
+    version.changeset.
+      reject{ |_, values| values[0].blank? && values[1].blank? }.
+      keys.map{ |key| key.gsub('_id', '').tr('_', ' ')}.join(', ').
+      reverse.sub(',', ' dna ').reverse
+  end
+
+  def change_creator_link(user_id)
+    user = User.find_by(id: user_id)
+    if user
+      link_to user.name, admin_user_path(id: user_id)
+    else
+      'Someone (probably via the console)'
+    end
+  end
+
+  # Recieves a PaperTrail::Version object
+  # Returns object in its current state if its alive
+  # Returns object as it was before version's change(unless its a create event's version)
+  # Else Returns object as it was after version's change
+  def get_version_object(version)
+    version.item || version.reify || version.next.reify
+  end
+
+  def event_change_description(version)
+    case
+    when version.event == 'create' then 'submitted new'
+
+    when version.changeset['state']
+      case version.changeset['state'][1]
+      when 'unconfirmed' then 'accepted'
+      when 'withdrawn' then 'withdrew'
+      when 'canceled', 'rejected', 'confirmed' then version.changeset['state'][1]
+      when 'new' then 'resubmitted'
+      end
+
+    when version.changeset['start_time'] && version.changeset['start_time'][0].nil?
+      'scheduled'
+
+    when version.changeset['start_time'] && version.changeset['start_time'][1].nil?
+      'unscheduled'
+
+    else
+      "updated #{updated_attributes(version)} of"
+    end
+  end
+
+  def users_role_change_description(version)
+    version.event == 'create' ? 'added' : 'removed'
+  end
+
+  def subscription_change_description(version)
+    user = get_version_object(version).user
+    user_name = user.name unless user.id.to_s == version.whodunnit
+    version.event == 'create' ? "subscribed #{user_name} to" : "unsubscribed #{user_name} from"
+  end
+
+  def registration_change_description(version)
+    if version.item_type == 'Registration'
+      user = get_version_object(version).user
+    else
+      registration_id = get_version_object(version).registration_id
+      registration_last_version = PaperTrail::Version.where(item_type: 'Registration', item_id: registration_id).last
+      user = get_version_object(registration_last_version).user
+    end
+
+    if user.id.to_s == version.whodunnit
+      case version.event
+      when 'create' then 'registered to'
+      when 'update' then "updated #{updated_attributes(version)} of the registration for"
+      when 'destroy' then 'unregistered  from'
+      end
+    else
+      case version.event
+      when 'create' then "registered #{user.name} to"
+      when 'update' then "updated #{updated_attributes(version)} of  #{user.name}'s registration for"
+      when 'destroy' then "unregistered #{user.name} from"
+      end
+    end
+  end
+
+  def comment_change_description(version)
+    user = get_version_object(version).user
+    if version.event == 'create'
+      version.previous.nil? ? 'commented on' : "re-added #{user.name}'s comment on"
+    else
+      "deleted #{user.name}'s comment on"
+    end
+  end
+
+  def vote_change_description(version)
+    user = get_version_object(version).user
+    if version.event == 'create'
+      version.previous.nil? ? 'voted on' : "re-added #{user.name}'s vote on"
+    elsif version.event == 'update'
+      "updated #{user.name}'s vote on"
+    else
+      "deleted #{user.name}'s vote on"
+    end
+  end
+
+  def user_change_description(version)
+    if version.event == 'create'
+     change_creator_link(version.item_id) + ' signed up'
+    elsif version.event == 'update'
+      if version.changeset.keys.include?('reset_password_sent_at')
+        'Someone requested password reset of'
+      elsif version.changeset.keys.include?('confirmed_at') && version.changeset['confirmed_at'][0].nil?
+        (version.whodunnit.nil? ? change_creator_link(version.item_id) : change_creator_link(version.whodunnit)) + ' confirmed account of'
+      elsif version.changeset.keys.include?('confirmed_at') && version.changeset['confirmed_at'][1].nil?
+        change_creator_link(version.whodunnit) + ' unconfirmed account of'
+      else
+        change_creator_link(version.whodunnit) + " updated #{updated_attributes(version)} of"
+      end
+    end
+  end
 end
diff --git a/app/models/ability.rb b/app/models/ability.rb
index 2210a7cd..8891aabf 100644
--- a/app/models/ability.rb
+++ b/app/models/ability.rb
@@ -114,6 +114,14 @@ class Ability
     # for admins
     can :manage, :all if user.is_admin
 
+    cannot :revert_object, PaperTrail::Version do |version|
+      (version.event == 'create' && %w(Conference User Event).include?(version.item_type))
+    end
+
+    cannot :revert_attribute, PaperTrail::Version do |version|
+      version.event != 'update' || version.item.nil?
+    end
+
     cannot :destroy, Program
     # Do not delete venue, when there are rooms being used
     cannot :destroy, Venue do |venue|
@@ -168,6 +176,10 @@ class Ability
     can [:edit, :update, :toggle_user], Role do |role|
       role.resource_type == 'Conference' && (conf_ids_for_organizer.include? role.resource_id)
     end
+
+    can [:index, :revert_object, :revert_attribute], PaperTrail::Version do |version|
+      version.item_type == 'User' || (conf_ids_for_organizer.include? version.conference_id)
+    end
   end
 
   def signed_in_with_cfp_role(user)
diff --git a/app/models/campaign.rb b/app/models/campaign.rb
index 66257371..28cddbbd 100644
--- a/app/models/campaign.rb
+++ b/app/models/campaign.rb
@@ -4,6 +4,8 @@ class Campaign < ActiveRecord::Base
   has_many :targets, dependent: :nullify
   belongs_to :conference
 
+  has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
+
   ##
   # Returns the utm parameters formatted as url.
   #
diff --git a/app/models/cfp.rb b/app/models/cfp.rb
index 3cd15bf7..3e516ae6 100644
--- a/app/models/cfp.rb
+++ b/app/models/cfp.rb
@@ -1,6 +1,7 @@
 # cannot delete program if there are events submitted
 
 class Cfp < ActiveRecord::Base
+  has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
   belongs_to :program
 
   validates :program_id, presence: true
@@ -68,4 +69,8 @@ class Cfp < ActiveRecord::Base
     errors.
     add(:start_date, "can't be after the end date") if start_date && end_date && start_date > end_date
   end
+
+  def conference_id
+    program.conference_id
+  end
 end
diff --git a/app/models/comment.rb b/app/models/comment.rb
index 1f501c3f..31531f8e 100644
--- a/app/models/comment.rb
+++ b/app/models/comment.rb
@@ -13,6 +13,8 @@ class Comment < ActiveRecord::Base
   # NOTE: Comments belong to a user
   belongs_to :user
 
+  has_paper_trail on: [:create, :destroy], meta: { conference_id: :conference_id }
+
   # Helper class method that allows you to build a comment
   # by passing a commentable object, a user_id, and comment text
   # example in readme
@@ -58,4 +60,8 @@ class Comment < ActiveRecord::Base
   def send_notification
     EventCommentMailJob.perform_later(self)
   end
+
+  def conference_id
+    commentable.program.conference_id
+  end
 end
diff --git a/app/models/commercial.rb b/app/models/commercial.rb
index 13540447..a2245d07 100644
--- a/app/models/commercial.rb
+++ b/app/models/commercial.rb
@@ -3,6 +3,8 @@ class Commercial < ActiveRecord::Base
 
   belongs_to :commercialable, polymorphic: true
 
+  has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
+
   validates :url, presence: true
   validates :url, format: URI::regexp(%w(http https))
 
@@ -41,4 +43,12 @@ class Commercial < ActiveRecord::Base
         speakerdeck
     )
   end
+
+  def conference_id
+    case commercialable_type
+    when 'Conference' then commercialable_id
+    when 'Event' then Event.find(commercialable_id).program.conference_id
+    when 'Venue' then Venue.find(commercialable_id).conference_id
+    end
+  end
 end
diff --git a/app/models/conference.rb b/app/models/conference.rb
index 9079bd71..55cd8ed5 100644
--- a/app/models/conference.rb
+++ b/app/models/conference.rb
@@ -9,7 +9,7 @@ class Conference < ActiveRecord::Base
 
   default_scope { order('start_date DESC') }
 
-  has_paper_trail
+  has_paper_trail ignore: [:updated_at, :guid, :revision, :events_per_week], meta: { conference_id: :id }
 
   has_and_belongs_to_many :questions
 
diff --git a/app/models/contact.rb b/app/models/contact.rb
index 9f0b8c0f..3f8216df 100644
--- a/app/models/contact.rb
+++ b/app/models/contact.rb
@@ -1,4 +1,6 @@
 class Contact < ActiveRecord::Base
+  has_paper_trail on: [:update], ignore: [:updated_at], meta: { conference_id: :conference_id }
+
   belongs_to :conference
 
   validates :conference, presence: true
diff --git a/app/models/difficulty_level.rb b/app/models/difficulty_level.rb
index 9f066422..b5d971a7 100644
--- a/app/models/difficulty_level.rb
+++ b/app/models/difficulty_level.rb
@@ -2,7 +2,10 @@ class DifficultyLevel < ActiveRecord::Base
   belongs_to :program
   has_many :events, dependent: :nullify
 
+  has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
+
   validates :title, presence: true
+
   validates :color, format: /\A#[0-9A-F]{6}\z/
 
   before_validation :capitalize_color
@@ -12,4 +15,8 @@ class DifficultyLevel < ActiveRecord::Base
   def capitalize_color
     self.color = color.upcase if color.present?
   end
+
+  def conference_id
+    program.conference_id
+  end
 end
diff --git a/app/models/email_settings.rb b/app/models/email_settings.rb
index c9632932..5f7c8296 100644
--- a/app/models/email_settings.rb
+++ b/app/models/email_settings.rb
@@ -1,6 +1,8 @@
 class EmailSettings < ActiveRecord::Base
   belongs_to :conference
 
+  has_paper_trail on: [:update], ignore: [:updated_at], meta: { conference_id: :conference_id }
+
   def get_values(conference, user, event = nil)
     h = {
       'email' => user.email,
diff --git a/app/models/event.rb b/app/models/event.rb
index dfc5f664..d2446847 100644
--- a/app/models/event.rb
+++ b/app/models/event.rb
@@ -1,6 +1,6 @@
 class Event < ActiveRecord::Base
   include ActiveRecord::Transitions
-  has_paper_trail
+  has_paper_trail on: [:create, :update], ignore: [:updated_at, :guid, :week], meta: { conference_id: :conference_id }
 
   acts_as_commentable
 
@@ -280,7 +280,9 @@ class Event < ActiveRecord::Base
 
   def set_week
     self.week = created_at.strftime('%W')
-    save!
+    self.without_versioning do
+      self.save!
+    end
   end
 
   def before_end_of_conference
@@ -288,4 +290,8 @@ class Event < ActiveRecord::Base
         add(:created_at, "can't be after the conference end date!") if program.conference && program.conference.end_date &&
         (Date.today > program.conference.end_date)
   end
+
+  def conference_id
+    program.conference_id
+  end
 end
diff --git a/app/models/event_type.rb b/app/models/event_type.rb
index fd59aa0a..b00b36cd 100644
--- a/app/models/event_type.rb
+++ b/app/models/event_type.rb
@@ -2,6 +2,8 @@ class EventType < ActiveRecord::Base
   belongs_to :program
   has_many :events, dependent: :restrict_with_error
 
+  has_paper_trail meta: { conference_id: :conference_id }
+
   validates :title, presence: true
   validates :length, numericality: {greater_than: 0}
   validates :minimum_abstract_length, presence: true
@@ -28,4 +30,8 @@ class EventType < ActiveRecord::Base
   def capitalize_color
     self.color = color.upcase if color.present?
   end
+
+  def conference_id
+    program.conference_id
+  end
 end
diff --git a/app/models/events_registration.rb b/app/models/events_registration.rb
index 187f4189..fcebd69f 100644
--- a/app/models/events_registration.rb
+++ b/app/models/events_registration.rb
@@ -4,9 +4,17 @@ class EventsRegistration < ActiveRecord::Base
 
   has_one :user, through: :registration
 
+  has_paper_trail meta: { conference_id: :conference_id }
+
   delegate :name, to: :registration
   delegate :email, to: :registration
 
   validates :event, :registration, presence: true
   validates :event, uniqueness: { scope: :registration }
+
+  private
+
+  def conference_id
+    registration.conference_id
+  end
 end
diff --git a/app/models/lodging.rb b/app/models/lodging.rb
index 48031eba..21e4a8b0 100644
--- a/app/models/lodging.rb
+++ b/app/models/lodging.rb
@@ -1,6 +1,8 @@
 class Lodging < ActiveRecord::Base
   belongs_to :conference
 
+  has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
+
   validates :name, presence: true
 
   mount_uploader :picture, PictureUploader, mount_on: :photo_file_name
diff --git a/app/models/program.rb b/app/models/program.rb
index 280471a2..49d84937 100644
--- a/app/models/program.rb
+++ b/app/models/program.rb
@@ -1,6 +1,8 @@
 # cannot delete program if there are events submitted
 
 class Program < ActiveRecord::Base
+  has_paper_trail on: [:update], ignore: [:updated_at], meta: { conference_id: :conference_id }
+
   belongs_to :conference
 
   has_one :cfp, dependent: :destroy
@@ -53,8 +55,8 @@ class Program < ActiveRecord::Base
   validate :voting_start_date_before_end_date
   validate :voting_dates_exist
 
-  before_create :create_event_types
-  before_create :create_difficulty_levels
+  after_create :create_event_types
+  after_create :create_difficulty_levels
   validate :check_languages_format
 
   # Returns all event_schedules for the selected schedule ordered by start_time
@@ -157,12 +159,12 @@ class Program < ActiveRecord::Base
   # Creates default EventTypes for this Conference. Used as before_create.
   #
   def create_event_types
-    event_types << EventType.create(title: 'Talk', length: 30, color: '#FF0000', description: 'Presentation in lecture format',
-                                    minimum_abstract_length: 0,
-                                    maximum_abstract_length: 500)
-    event_types << EventType.create(title: 'Workshop', length: 60, color: '#0000FF', description: 'Interactive hands-on practice',
-                                    minimum_abstract_length: 0,
-                                    maximum_abstract_length: 500)
+    EventType.create(title: 'Talk', length: 30, color: '#FF0000', description: 'Presentation in lecture format',
+                     minimum_abstract_length: 0,
+                     maximum_abstract_length: 500, program_id: self.id)
+    EventType.create(title: 'Workshop', length: 60, color: '#0000FF', description: 'Interactive hands-on practice',
+                     minimum_abstract_length: 0,
+                     maximum_abstract_length: 500, program_id: self.id)
     true
   end
 
@@ -170,15 +172,15 @@ class Program < ActiveRecord::Base
   # Creates default DifficultyLevels for this Conference. Used as before_create.
   #
   def create_difficulty_levels
-    difficulty_levels << DifficultyLevel.create(title: 'Easy',
-                                                description: 'Events are understandable for everyone without knowledge of the topic.',
-                                                color: '#70EF69')
-    difficulty_levels << DifficultyLevel.create(title: 'Medium',
-                                                description: 'Events require a basic understanding of the topic.',
-                                                color: '#EEEF69')
-    difficulty_levels << DifficultyLevel.create(title: 'Hard',
-                                                description: 'Events require expert knowledge of the topic.',
-                                                color: '#EF6E69')
+    DifficultyLevel.create(title: 'Easy',
+                           description: 'Events are understandable for everyone without knowledge of the topic.',
+                           color: '#70EF69', program_id: self.id)
+    DifficultyLevel.create(title: 'Medium',
+                           description: 'Events require a basic understanding of the topic.',
+                           color: '#EEEF69', program_id: self.id)
+    DifficultyLevel.create(title: 'Hard',
+                           description: 'Events require expert knowledge of the topic.',
+                           color: '#EF6E69', program_id: self.id)
     true
   end
 
diff --git a/app/models/registration.rb b/app/models/registration.rb
index d6a549fc..99e6766c 100644
--- a/app/models/registration.rb
+++ b/app/models/registration.rb
@@ -7,7 +7,9 @@ class Registration < ActiveRecord::Base
   has_and_belongs_to_many :vchoices
 
   has_many :events_registrations
-  has_many :events, through: :events_registrations
+  has_many :events, through: :events_registrations, dependent: :destroy
+
+  has_paper_trail ignore: [:updated_at, :week], meta: { conference_id: :conference_id }
 
   accepts_nested_attributes_for :user
   accepts_nested_attributes_for :qanswers
@@ -75,7 +77,9 @@ class Registration < ActiveRecord::Base
 
   def set_week
     self.week = created_at.strftime('%W')
-    save!
+    without_versioning do
+      save!
+    end
   end
 
   def registration_limit_not_exceed
diff --git a/app/models/registration_period.rb b/app/models/registration_period.rb
index b4e04a95..a7c251ac 100644
--- a/app/models/registration_period.rb
+++ b/app/models/registration_period.rb
@@ -1,6 +1,8 @@
 class RegistrationPeriod < ActiveRecord::Base
   belongs_to :conference
 
+  has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
+
   validates :start_date, :end_date, presence: true
   validate :before_end_of_conference
   validate :start_date_before_end_date
diff --git a/app/models/role.rb b/app/models/role.rb
index 9673e700..f194ad91 100644
--- a/app/models/role.rb
+++ b/app/models/role.rb
@@ -1,6 +1,10 @@
 class Role < ActiveRecord::Base
   belongs_to :resource, polymorphic: true
-  has_and_belongs_to_many :users, join_table: :users_roles
+  has_many :users_roles
+  has_many :users, through: :users_roles
+
+  has_paper_trail on: [:update], only: [:name, :description], meta: { conference_id: :resource_id }
+
   before_destroy :cancel
   scopify
 
diff --git a/app/models/room.rb b/app/models/room.rb
index 87dfb848..a789e2e5 100644
--- a/app/models/room.rb
+++ b/app/models/room.rb
@@ -2,6 +2,8 @@ class Room < ActiveRecord::Base
   belongs_to :venue
   has_many :event_schedules, dependent: :nullify
 
+  has_paper_trail ignore: [:guid], meta: { conference_id: :conference_id }
+
   before_create :generate_guid
 
   validates :name, :venue_id, presence: true
@@ -14,4 +16,8 @@ class Room < ActiveRecord::Base
     guid = SecureRandom.urlsafe_base64
     self.guid = guid
   end
+
+  def conference_id
+    venue.conference_id
+  end
 end
diff --git a/app/models/splashpage.rb b/app/models/splashpage.rb
index 1f7a5ff5..15447aa9 100644
--- a/app/models/splashpage.rb
+++ b/app/models/splashpage.rb
@@ -1,3 +1,5 @@
 class Splashpage < ActiveRecord::Base
   belongs_to :conference
+
+  has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
 end
diff --git a/app/models/sponsor.rb b/app/models/sponsor.rb
index 7a843e63..985cef44 100644
--- a/app/models/sponsor.rb
+++ b/app/models/sponsor.rb
@@ -2,6 +2,8 @@ class Sponsor < ActiveRecord::Base
   belongs_to :sponsorship_level
   belongs_to :conference
 
+  has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
+
   mount_uploader :picture, PictureUploader, mount_on: :logo_file_name
 
   validates_presence_of :name, :website_url, :sponsorship_level
diff --git a/app/models/sponsorship_level.rb b/app/models/sponsorship_level.rb
index f947a60b..d4630971 100644
--- a/app/models/sponsorship_level.rb
+++ b/app/models/sponsorship_level.rb
@@ -3,4 +3,6 @@ class SponsorshipLevel < ActiveRecord::Base
   belongs_to :conference
   acts_as_list scope: :conference
   has_many :sponsors
+
+  has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
 end
diff --git a/app/models/subscription.rb b/app/models/subscription.rb
index 7f39adf3..1ee97ca6 100644
--- a/app/models/subscription.rb
+++ b/app/models/subscription.rb
@@ -3,5 +3,7 @@ class Subscription < ActiveRecord::Base
   belongs_to :conference
   belongs_to :user
 
+  has_paper_trail on: [:create, :destroy], ignore: [:updated_at], meta: { conference_id: :conference_id }
+
   validates_uniqueness_of :user_id, scope: :conference_id, message: 'already subscribed!'
 end
diff --git a/app/models/target.rb b/app/models/target.rb
index ea91b38a..2de7c757 100644
--- a/app/models/target.rb
+++ b/app/models/target.rb
@@ -3,6 +3,8 @@ class Target < ActiveRecord::Base
 
   default_scope { order('due_date ASC') }
 
+  has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
+
   def self.units
     {
       registrations: 'Registration',
diff --git a/app/models/ticket.rb b/app/models/ticket.rb
index 54f5c3d7..8a620f79 100644
--- a/app/models/ticket.rb
+++ b/app/models/ticket.rb
@@ -3,6 +3,8 @@ class Ticket < ActiveRecord::Base
   has_many :ticket_purchases, dependent: :destroy
   has_many :buyers, -> { distinct }, through: :ticket_purchases, source: :user
 
+  has_paper_trail meta: { conference_id: :conference_id }
+
   monetize :price_cents, with_model_currency: :price_currency
 
   # This validation is for the sake of simplicity.
diff --git a/app/models/track.rb b/app/models/track.rb
index 11db2e8a..1d94f7d5 100644
--- a/app/models/track.rb
+++ b/app/models/track.rb
@@ -2,6 +2,8 @@ class Track < ActiveRecord::Base
   belongs_to :program
   has_many :events, dependent: :nullify
 
+  has_paper_trail only: [:name, :description, :color], meta: { conference_id: :conference_id }
+
   before_create :generate_guid
   validates :name, presence: true
   validates :color, format: /\A#[0-9A-F]{6}\z/
@@ -21,4 +23,8 @@ class Track < ActiveRecord::Base
   def capitalize_color
     self.color = color.upcase if color.present?
   end
+
+  def conference_id
+    program.conference_id
+  end
 end
diff --git a/app/models/user.rb b/app/models/user.rb
index d3c847a2..1e86473d 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -6,6 +6,12 @@ end
 
 class User < ActiveRecord::Base
   rolify
+  has_many :users_roles
+  has_many :roles, through: :users_roles, dependent: :destroy
+
+  has_paper_trail on: [:create, :update], ignore: [:sign_in_count, :remember_created_at, :current_sign_in_at, :last_sign_in_at, :current_sign_in_ip, :last_sign_in_ip, :unconfirmed_email,
+                                                   :avatar_content_type, :avatar_file_size, :avatar_updated_at, :updated_at, :confirmation_sent_at, :confirmation_token, :reset_password_token]
+
   include Gravtastic
   gravtastic size: 32
 
@@ -72,7 +78,7 @@ class User < ActiveRecord::Base
   end
 
   def name
-    self[:name] || username
+    self[:name].blank? ? username : self[:name]
   end
 
   ##
diff --git a/app/models/users_role.rb b/app/models/users_role.rb
new file mode 100644
index 00000000..3a3afaba
--- /dev/null
+++ b/app/models/users_role.rb
@@ -0,0 +1,12 @@
+class UsersRole < ActiveRecord::Base
+  belongs_to :role
+  belongs_to :user
+
+  has_paper_trail on: [:create, :destroy], meta: { conference_id: :conference_id }
+
+  private
+
+  def conference_id
+    role.resource_id
+  end
+end
diff --git a/app/models/venue.rb b/app/models/venue.rb
index aa65816c..302171b5 100644
--- a/app/models/venue.rb
+++ b/app/models/venue.rb
@@ -4,6 +4,8 @@ class Venue < ActiveRecord::Base
   has_many :rooms, dependent: :destroy
   before_create :generate_guid
 
+  has_paper_trail ignore: [:updated_at, :guid], meta: { conference_id: :conference_id }
+
   accepts_nested_attributes_for :commercial, allow_destroy: true
   validates :name, :street, :city, :country, presence: true
 
diff --git a/app/models/vote.rb b/app/models/vote.rb
index e7da3c17..5b0e3fe7 100644
--- a/app/models/vote.rb
+++ b/app/models/vote.rb
@@ -1,5 +1,14 @@
 class Vote < ActiveRecord::Base
   belongs_to :user
   belongs_to :event
+
+  has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
+
   delegate :name, to: :user
+
+  private
+
+  def conference_id
+    event.program.conference_id
+  end
 end
diff --git a/app/views/admin/versions/_object_changes.html.haml b/app/views/admin/versions/_object_changes.html.haml
new file mode 100644
index 00000000..b61d3c83
--- /dev/null
+++ b/app/views/admin/versions/_object_changes.html.haml
@@ -0,0 +1,28 @@
+.col-md-10.col-md-offset-1.changeset{id: "changeset-#{version.id}"}
+  %br
+  %br
+  %table.table.table-bordered.table-hover
+    %thead
+      %tr
+        %th Updated Attribute
+        - if version.event != 'create'
+          %th Previous Value
+        - if version.event != 'destroy'
+          %th New Value
+        - if can? :revert_attribute, version
+          %th Action
+    %tbody
+      - if version.event!= 'destroy'
+        - version.changeset.reject{ |_, values| values[0].blank? && values[1].blank? }.each do |attribute, values|
+          %tr
+            %td= attribute
+            - if version.event != 'create'
+              %td= values[0].blank? ?  '-' : values[0]
+            %td= values[1].blank? ?  '-' : values[1]
+            - if can? :revert_attribute, version
+              %td= link_to 'Revert', admin_revision_history_revert_attribute_path(id: version.id, attribute: attribute), class: 'btn btn-sm btn-primary', data: { confirm: "Are you sure you want to revert #{attribute}?" }
+      - else
+        - version.reify.attributes.each do |attribute, value|
+          %tr
+            %td= attribute
+            %td= value.blank? ?  '-' : value
diff --git a/app/views/admin/versions/_object_desc_and_link.html.haml b/app/views/admin/versions/_object_desc_and_link.html.haml
new file mode 100644
index 00000000..a34f4c4a
--- /dev/null
+++ b/app/views/admin/versions/_object_desc_and_link.html.haml
@@ -0,0 +1,158 @@
+- if version.item_type == 'UsersRole'
+  - users_role = get_version_object(version)
+  = 'role'
+  = link_to users_role.role.name, admin_conference_role_path(conference_id: Conference.find(version.conference_id).short_title, id: users_role.role.name)
+  = version.event == 'create' ? 'to' : 'from'
+  = 'user'
+  = link_to users_role.user.name, admin_user_path(id: users_role.user.id)
+
+- elsif version.item_type == 'Subscription' || version.item_type == 'Registration'
+  = 'conference'
+  = link_to Conference.find(version.conference_id).title,
+          admin_conference_registrations_path(conference_id: Conference.find(version.conference_id).short_title)
+
+- elsif version.item_type == 'Commercial'
+  - commercial_last_version = get_version_object(PaperTrail::Version.where(item_type: version.item_type, item_id: version.item_id).last)
+  - commercialable_last_version = get_version_object(PaperTrail::Version.where(item_type: commercial_last_version.commercialable_type,
+                                                          item_id: commercial_last_version.commercialable_id).last)
+
+  - case commercial_last_version.commercialable_type
+  - when 'Event'
+    =  link_to 'commercial',
+            edit_admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title,
+                id: commercialable_last_version.id, anchor: 'commercials-content')
+    = "in event #{commercialable_last_version.title}"
+
+  - when 'Venue'
+    - if Venue.find_by(id: commercialable_last_version.id)
+      =  link_to 'commercial',
+              edit_admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title,
+                  id: commercialable_last_version.id, anchor: 'commercials-content')
+    - else
+      = 'commercial'
+    = "in venue #{commercialable_last_version.name}"
+
+  - when 'Conference'
+    = link_to 'commercial',
+            admin_conference_commercials_path(conference_id: Conference.find(version.conference_id).short_title)
+
+- elsif %w(EventsRegistration Comment Vote).include?(version.item_type)
+  = 'event'
+  - event_id = get_version_object(version).try(:event_id) || get_version_object(version).try(:commentable_id)
+  = link_to Event.find(event_id).title,
+          admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title, id: event_id)
+
+- elsif version.item_type =='Target'
+  = 'target'
+  - if version.item
+    = link_to Target.find(version.item_id).to_s,
+            admin_conference_targets_path(conference_id: Conference.find(version.conference_id).short_title)
+  - else
+    = PaperTrail::Version.where(item_type: 'Target', item_id: version.item_id).last.reify.to_s
+
+- elsif  version.item
+  - case version.item_type
+  - when 'Conference'
+    = 'conference'
+    = link_to Conference.find(version.conference_id).title,
+            edit_admin_conference_path(id: Conference.find(version.conference_id).short_title)
+
+  - when 'RegistrationPeriod'
+    = link_to 'registration period',
+            admin_conference_registration_period_path(conference_id: Conference.find(version.conference_id).short_title)
+
+  - when 'Contact'
+    = link_to 'contact details',
+            edit_admin_conference_contact_path(conference_id: Conference.find(version.conference_id).short_title)
+
+  - when 'Program'
+    = link_to 'program',
+            admin_conference_program_path(conference_id: Conference.find(version.conference_id).short_title)
+
+  - when 'Cfp'
+    = link_to 'cfp',
+            admin_conference_program_cfp_path(conference_id: Conference.find(version.conference_id).short_title)
+
+  - when 'Track'
+    = 'track'
+    = link_to Track.find(version.item_id).name,
+            admin_conference_program_track_path(conference_id: Conference.find(version.conference_id).short_title, id: version.item_id)
+
+  - when 'Event'
+    = 'event'
+    = link_to Event.find(version.item_id).title,
+            admin_conference_program_event_path(conference_id: Conference.find(version.conference_id).short_title, id: version.item_id)
+
+  - when 'EventType'
+    = 'event type'
+    = link_to EventType.find(version.item_id).title,
+            admin_conference_program_event_types_path(conference_id: Conference.find(version.conference_id).short_title)
+
+  - when 'Role'
+    = 'role'
+    = link_to Role.find(version.item_id).name,
+            admin_conference_role_path(conference_id: Conference.find(version.conference_id).short_title, id: version.item.name)
+
+  - when 'Venue'
+    = 'venue'
+    = link_to Venue.find(version.item_id).name,
+            admin_conference_venue_path(conference_id: Conference.find(version.conference_id).short_title)
+
+  - when 'Lodging'
+    = 'lodging'
+    = link_to Lodging.find(version.item_id).name,
+            admin_conference_lodgings_path(conference_id: Conference.find(version.conference_id).short_title)
+
+  - when 'Room'
+    = 'room'
+    = link_to Room.find(version.item_id).name,
+            admin_conference_venue_rooms_path(conference_id: Conference.find(version.conference_id).short_title)
+
+  - when 'Sponsor'
+    = 'sponsor'
+    = link_to Sponsor.find(version.item_id).name,
+            admin_conference_sponsors_path(conference_id: Conference.find(version.conference_id).short_title)
+
+  - when 'SponsorshipLevel'
+    = 'sponsorship level'
+    = link_to SponsorshipLevel.find(version.item_id).title,
+            admin_conference_sponsorship_levels_path(conference_id: Conference.find(version.conference_id).short_title)
+
+  - when 'Ticket'
+    = 'ticket'
+    = link_to Ticket.find(version.item_id).title,
+            admin_conference_ticket_path(conference_id: Conference.find(version.conference_id).short_title, id: version.item_id)
+
+  - when 'Campaign'
+    = 'campaign'
+    = link_to Campaign.find(version.item_id).name,
+            admin_conference_campaigns_path(conference_id: Conference.find(version.conference_id).short_title)
+
+  - when 'DifficultyLevel'
+    = 'difficulty level'
+    = link_to DifficultyLevel.find(version.item_id).title,
+            admin_conference_program_difficulty_level_path(conference_id: Conference.find(version.conference_id).short_title, id: version.item_id)
+
+  - when 'Splashpage'
+    = link_to 'splashpage',
+            admin_conference_splashpage_path(conference_id: Conference.find(version.conference_id).short_title)
+
+  - when 'EmailSettings'
+    = link_to 'email settings',
+            admin_conference_emails_path(conference_id: Conference.find(version.conference_id).short_title)
+
+  - when 'User'
+    - if version.event == 'update'
+      = 'user'
+      = link_to User.find(version.item_id).name, admin_user_path(id: version.item_id)
+
+- else
+  = version.item_type.underscore.tr('_', ' ')
+  / The last deleted version's name/title is used to describe all the changes in object
+  - last_deleted_version = PaperTrail::Version.where(item_type: version.item_type, item_id: version.item_id).last.reify
+  = last_deleted_version.try(:title) || last_deleted_version.try(:name)
+
+- unless %w(Conference Subscription Registration User).include?(version.item_type)
+  = "in conference"
+  = link_to Conference.find(version.conference_id).short_title,
+          edit_admin_conference_path(id: Conference.find(version.conference_id).short_title)
diff --git a/app/views/admin/versions/index.html.haml b/app/views/admin/versions/index.html.haml
new file mode 100644
index 00000000..af604820
--- /dev/null
+++ b/app/views/admin/versions/index.html.haml
@@ -0,0 +1,77 @@
+.row
+  .col-md-12
+    .page-header
+      %h1 Revision History
+      %p.text-muted
+        Log of changes made to conferences and associated resources
+
+%table.table.table-striped.table-bordered.table-hover#versionstable
+  %thead
+    %td ID
+    %td Description
+    %td Actions
+  %tbody
+    - @versions.each do |version|
+      %tr
+        %td.col-md-1
+          = version.id
+        %td.col-md-9
+          %p
+            = change_creator_link(version.whodunnit) unless version.item_type == 'User'
+
+            - case version.item_type
+            - when 'Event'
+              = event_change_description(version)
+
+            -when 'UsersRole'
+              = users_role_change_description(version)
+
+            - when 'Subscription'
+              = subscription_change_description(version)
+
+            - when 'Registration', 'EventsRegistration'
+              = registration_change_description(version)
+
+            - when 'Comment'
+              = comment_change_description(version)
+
+            - when 'Vote'
+              = vote_change_description(version)
+
+            - when 'User'
+              = user_change_description(version)
+
+            - else
+              - if version.event == 'create'
+                = 'created new'
+              - elsif version.event == 'update'
+                = "updated #{updated_attributes(version)} of"
+              - else
+                = 'deleted'
+
+            =  render partial: 'object_desc_and_link', locals: { version: version }
+
+            %small.text-muted
+              = distance_of_time_in_words(Time.now,version.created_at) + ' ago'
+              %br
+              = "(#{version.created_at.strftime('%B %-d, %Y %H:%M')})"
+
+          %br
+          = render partial: 'object_changes', locals: { version: version }
+
+        %td.col-md-2
+          .btn-group{role: 'group'}
+            %a.btn.btn-success.btn-sm.show-changeset{id: version.id} View Changes
+            - if can? :revert_object, version
+              %button.btn.btn-default.dropdown-toggle.btn-sm.btn-primary{'data-toggle' => 'dropdown', type: 'button'}
+                Revert
+                %span.caret
+              %ul.dropdown-menu
+                %li= link_to 'All Changes', admin_revision_history_revert_object_path(id: version.id), data: { confirm: 'Are you sure you want to revert this change?' }
+
+                - if can? :revert_attribute, version
+                  %li.divider{role: 'separator'}
+                  - version.changeset.reject{ |_, values| values[0].blank? && values[1].blank? }.each do |attribute, values|
+                    %li= link_to attribute, admin_revision_history_revert_attribute_path(id: version.id, attribute: attribute), data: { confirm: "Are you sure you want to revert #{attribute}?" }
+            - else
+              %button.btn.btn-sm.btn-primary.disabled Revert
diff --git a/app/views/layouts/_admin_sidebar_index.html.haml b/app/views/layouts/_admin_sidebar_index.html.haml
index b7a5e9c6..b00bb546 100644
--- a/app/views/layouts/_admin_sidebar_index.html.haml
+++ b/app/views/layouts/_admin_sidebar_index.html.haml
@@ -27,3 +27,8 @@
       = link_to(admin_users_path) do
         %span.fa.fa-user
         Users
+  - if can? :index, PaperTrail::Version.new(item_type: 'User')
+    %li
+      = link_to(admin_revision_history_path) do
+        %span.fa.fa-history
+        Revision History
diff --git a/app/views/layouts/_user_menu.html.haml b/app/views/layouts/_user_menu.html.haml
index 26f02b5a..e626ddd9 100644
--- a/app/views/layouts/_user_menu.html.haml
+++ b/app/views/layouts/_user_menu.html.haml
@@ -44,3 +44,8 @@
     = link_to(admin_users_path) do
       %span.fa.fa-user
       Users
+- if can? :index, PaperTrail::Version.new(item_type: 'User')
+  %li
+    = link_to(admin_revision_history_path) do
+      %span.fa.fa-history
+      Revision History
diff --git a/config/routes.rb b/config/routes.rb
index 25c253e5..fdcf5e99 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -91,6 +91,10 @@ Osem::Application.routes.draw do
         end
       end
     end
+
+    get '/revision_history' => 'versions#index'
+    get '/revision_history/:id/revert_object' => 'versions#revert_object', as: 'revision_history_revert_object'
+    get '/revision_history/:id/revert_attribute' => 'versions#revert_attribute', as: 'revision_history_revert_attribute'
   end
 
   resources :conference, only: [:index, :show] do
diff --git a/db/migrate/20160524050538_add_conference_id_to_versions.rb b/db/migrate/20160524050538_add_conference_id_to_versions.rb
new file mode 100644
index 00000000..345218f1
--- /dev/null
+++ b/db/migrate/20160524050538_add_conference_id_to_versions.rb
@@ -0,0 +1,5 @@
+class AddConferenceIdToVersions < ActiveRecord::Migration
+  def change
+    add_column :versions, :conference_id, :integer
+  end
+end
diff --git a/db/migrate/20160614145614_add_id_to_users_roles.rb b/db/migrate/20160614145614_add_id_to_users_roles.rb
new file mode 100644
index 00000000..20153f96
--- /dev/null
+++ b/db/migrate/20160614145614_add_id_to_users_roles.rb
@@ -0,0 +1,5 @@
+class AddIdToUsersRoles < ActiveRecord::Migration
+  def change
+    add_column :users_roles, :id, :primary_key
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 8494999a..f6c5bed2 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -483,7 +483,7 @@ ActiveRecord::Schema.define(version: 20160704092023) do
   add_index "users", ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
   add_index "users", ["username"], name: "index_users_on_username", unique: true
 
-  create_table "users_roles", id: false, force: :cascade do |t|
+  create_table "users_roles", force: :cascade do |t|
     t.integer "role_id"
     t.integer "user_id"
   end
@@ -529,6 +529,7 @@ ActiveRecord::Schema.define(version: 20160704092023) do
     t.text     "object"
     t.text     "object_changes"
     t.datetime "created_at"
+    t.integer  "conference_id"
   end
 
   add_index "versions", ["item_type", "item_id"], name: "index_versions_on_item_type_and_item_id"
diff --git a/spec/controllers/admin/versions_controller_spec.rb b/spec/controllers/admin/versions_controller_spec.rb
new file mode 100644
index 00000000..4694837d
--- /dev/null
+++ b/spec/controllers/admin/versions_controller_spec.rb
@@ -0,0 +1,101 @@
+require 'spec_helper'
+
+describe Admin::VersionsController do
+
+  let!(:conference) { create(:conference, short_title: 'exampletitle', description: 'Example Description') }
+  let(:admin) { create(:admin) }
+
+  with_versioning do
+    describe 'GET #revert' do
+      before :each do
+        sign_in admin
+      end
+
+      it 'reverts all changes for update actions' do
+        conference.update_attributes(short_title: 'testtitle', description: 'Some random text')
+        get :revert_object, id: PaperTrail::Version.last.id
+        conference.reload
+        expect(conference.short_title).to eq 'exampletitle'
+        expect(conference.description).to eq 'Example Description'
+      end
+
+      it 'shows correct flash on trying to revert create event of a deleted object' do
+        creation_version_id = conference.program.event_types.first.versions.first.id
+        conference.program.event_types.first.destroy
+        get :revert_object, id: creation_version_id
+        expect(flash[:error]).to match('The item is already in the state that you are trying to revert it back to')
+      end
+
+      it 'reverting deletion of object  creates it again' do
+        conference.program.event_types.first.destroy
+        event_types_count = conference.program.event_types.count
+        get :revert_object, id: PaperTrail::Version.last.id
+        conference.reload
+        expect(PaperTrail::Version.last.event).to eq 'create'
+        expect(conference.program.event_types.count).to eq(event_types_count + 1)
+      end
+
+      it 'reverting creation of object deletes it ' do
+        create(:lodging, conference: conference)
+        get :revert_object, id: PaperTrail::Version.last.id
+        expect(PaperTrail::Version.last.event).to eq 'destroy'
+        expect(Lodging.count).to eq 0
+      end
+
+      it 'reverting creation of conference is not permitted' do
+        conference_count_before = Conference.count
+        get :revert_object, id: conference.versions.first.id
+        expect(flash[:alert]).to eq 'You are not authorized to access this page.'
+        expect(Conference.count).to eq(conference_count_before)
+      end
+    end
+
+    describe 'GET #revert_attribute' do
+      before :each do
+        sign_in admin
+      end
+
+      it 'reverts specified change for update actions' do
+        conference.update_attributes(short_title: 'testtitle', description: 'Some random text')
+        get :revert_attribute, id: PaperTrail::Version.last.id, attribute: 'short_title'
+        conference.reload
+        expect(conference.short_title).to eq 'exampletitle'
+        expect(conference.description).to eq 'Some random text'
+      end
+
+      it 'shows correct flash on trying to revert to the current state' do
+        conference.update_attributes(short_title: 'testtitle', description: 'Some random text')
+        conference.update_attributes(short_title: 'exampletitle')
+        get :revert_attribute, id: PaperTrail::Version.all[-2].id, attribute: 'short_title'
+        expect(flash[:error]).to match('The item is already in the state that you are trying to revert it back to')
+        expect(conference.short_title).to eq 'exampletitle'
+      end
+
+      it 'fails on trying to revert deleted object' do
+        conference.program.event_types.first.update_attributes(title: 'New Event Title')
+        conference.program.event_types.first.destroy
+        get :revert_attribute, id: PaperTrail::Version.all[-2].id, attribute: 'title'
+        conference.reload
+        expect(flash[:alert]).to eq 'You are not authorized to access this page.'
+      end
+
+      it 'fails on trying to revert creation event' do
+        create(:lodging, conference: conference)
+        get :revert_attribute, id: PaperTrail::Version.last.id, attribute: 'name'
+        expect(flash[:alert]).to eq 'You are not authorized to access this page.'
+      end
+
+      it 'revert fails when attribute is invalid' do
+        conference.update_attributes(short_title: 'testtitle', description: 'Some random text')
+        before_conference_title = conference.title
+        # Note: even though title is a valid attribute of conference, it was not updated in the change we are trying to revert
+        get :revert_attribute, id: PaperTrail::Version.last.id, attribute: 'title'
+        conference.reload
+        expect(conference.short_title).to eq 'testtitle'
+        expect(conference.description).to eq 'Some random text'
+        expect(conference.title).to eq(before_conference_title)
+        expect(flash[:error]).to match('Revert failed. Attribute missing or invalid')
+      end
+    end
+  end
+end
diff --git a/spec/factories/events.rb b/spec/factories/events.rb
index 3ae38109..c306cdf9 100644
--- a/spec/factories/events.rb
+++ b/spec/factories/events.rb
@@ -17,7 +17,6 @@ FactoryGirl.define do
 
     factory :event_full do
       difficulty_level
-      track
       after(:build) do |event|
         event.commercials << build(:event_commercial, commercialable: event)
         event.difficulty_level = build(:difficulty_level, program: event.program)
diff --git a/spec/factories/tracks.rb b/spec/factories/tracks.rb
index 3f35f539..1b7f8083 100644
--- a/spec/factories/tracks.rb
+++ b/spec/factories/tracks.rb
@@ -3,5 +3,6 @@ FactoryGirl.define do
     name { Faker::Commerce.department(2, true) }
     description { Faker::Lorem.sentence }
     color { Faker::Color.hex_color }
+    program
   end
 end
diff --git a/spec/features/ability_spec.rb b/spec/features/ability_spec.rb
index 7107056f..8ac8a1ec 100644
--- a/spec/features/ability_spec.rb
+++ b/spec/features/ability_spec.rb
@@ -102,6 +102,9 @@ feature 'Has correct abilities' do
 
     visit admin_conference_commercials_path(conference1.short_title)
     expect(current_path).to eq(admin_conference_commercials_path(conference1.short_title))
+
+    visit admin_revision_history_path
+    expect(current_path).to eq(admin_revision_history_path)
   end
 
   scenario 'when user is cfp' do
@@ -176,6 +179,9 @@ feature 'Has correct abilities' do
 
     visit admin_conference_commercials_path(conference2.short_title)
     expect(current_path).to eq(root_path)
+
+    visit admin_revision_history_path
+    expect(current_path).to eq(root_path)
   end
 
   scenario 'when user is info desk' do
@@ -250,5 +256,8 @@ feature 'Has correct abilities' do
 
     visit admin_conference_commercials_path(conference3.short_title)
     expect(current_path).to eq(root_path)
+
+    visit admin_revision_history_path
+    expect(current_path).to eq(root_path)
   end
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 77e1ad17..3ee6db15 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -22,6 +22,10 @@ ActiveRecord::Migration.maintain_test_schema!
 require 'capybara/poltergeist'
 require 'phantomjs'
 
+# Adds rspec helper provided by paper_trail
+# makes it easier to control when PaperTrail is enabled during testing.
+require 'paper_trail/frameworks/rspec'
+
 # Requires supporting ruby files with custom matchers and macros, etc, in
 # spec/support/ and its subdirectories. Files matching `spec/**/*_spec.rb` are
 # run as spec files by default. This means that files in spec/support that end

From 8a4a9552af5e13531aa9002b6184057dfc29e3e7 Mon Sep 17 00:00:00 2001
From: Nishanth Vijayan <nishanththegr8@gmail.com>
Date: Tue, 21 Jun 2016 12:22:12 +0530
Subject: [PATCH 2/3] Add rake task to set conference_id in pre-existing
 versions

---
 lib/tasks/version.rake | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 lib/tasks/version.rake

diff --git a/lib/tasks/version.rake b/lib/tasks/version.rake
new file mode 100644
index 00000000..084ff181
--- /dev/null
+++ b/lib/tasks/version.rake
@@ -0,0 +1,21 @@
+namespace :data do
+  desc 'Sets conference_id in all pre-existing PaperTrail::Version objects'
+  task set_conference_in_versions: :environment do
+
+    PaperTrail::Version.where(conference_id: nil, item_type: ['Conference', 'Event']).each do |version|
+      # All pre-existing versions are either of Conference or Event
+      if version.item_type == 'Conference'
+        version.update_attributes(conference_id: version.item_id)
+
+      elsif version.item_type == 'Event'
+        event = (version.item || version.reify || version.next.reify)
+        if event.try(:program)
+          version.update_attributes(conference_id: event.program.conference_id)
+        else
+          puts "Setting conference_id value failed for PaperTrail::Version object with ID=#{version.id}"
+        end
+      end
+    end
+    puts 'All done!'
+  end
+end

From fb03a87a8729f19ce2a82bdc96fbe180fda47681 Mon Sep 17 00:00:00 2001
From: Nishanth Vijayan <nishanththegr8@gmail.com>
Date: Wed, 22 Jun 2016 02:26:38 +0530
Subject: [PATCH 3/3] Feature test for Revision History

---
 spec/features/versions_spec.rb | 373 +++++++++++++++++++++++++++++++++
 1 file changed, 373 insertions(+)
 create mode 100644 spec/features/versions_spec.rb

diff --git a/spec/features/versions_spec.rb b/spec/features/versions_spec.rb
new file mode 100644
index 00000000..992061c7
--- /dev/null
+++ b/spec/features/versions_spec.rb
@@ -0,0 +1,373 @@
+require 'spec_helper'
+
+feature 'Version' do
+  let!(:conference) { create(:conference) }
+  let!(:organizer_role) { Role.find_by(name: 'organizer', resource: conference) }
+  let!(:organizer) { create(:user, role_ids: [organizer_role.id]) }
+
+  before(:each) do
+    sign_in organizer
+  end
+
+  scenario 'display changes in contact', feature: true, versioning: true, js: true do
+    visit edit_admin_conference_contact_path(conference.short_title)
+    fill_in 'contact_email', with: 'example@example.com'
+    fill_in 'contact_sponsor_email', with: 'sponsor@example.com'
+    fill_in 'contact_social_tag', with: 'example'
+    fill_in 'contact_googleplus', with: 'http:\\www.google.com'
+    click_button 'Update Contact'
+
+    visit admin_revision_history_path
+    expect(page).to have_text("#{organizer.name} updated social tag, email, googleplus and sponsor email of contact details in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in program', feature: true, versioning: true, js: true do
+    visit edit_admin_conference_program_path(conference.short_title)
+    fill_in 'program_rating', with: '4'
+    click_button 'Update Program'
+
+    visit admin_revision_history_path
+    expect(page).to have_text("#{organizer.name} updated rating of program in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in cfp', feature: true, versioning: true, js: true do
+    cfp = create(:cfp, program: conference.program)
+    cfp.update_attributes(start_date: (Date.today + 1).strftime('%d/%m/%Y'), end_date: (Date.today + 3).strftime('%d/%m/%Y'))
+    cfp.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) created new cfp in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) updated start date and end date of cfp in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) deleted cfp in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in registration_period', feature: true, versioning: true, js: true do
+    registration_period = create(:registration_period, conference: conference)
+    registration_period.update_attributes(start_date: (Date.today + 1).strftime('%d/%m/%Y'), end_date: (Date.today + 3).strftime('%d/%m/%Y'))
+    registration_period.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) created new registration period in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) updated start date and end date of registration period in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) deleted registration period in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in conference', feature: true, versioning: true, js: true do
+    new_conference = create(:conference, title: 'Test Conference')
+    organizer.add_role :organizer, new_conference
+    new_conference.update_attributes(title: 'New Con', short_title: 'NewCon')
+
+    visit admin_revision_history_path
+    expect(page).to have_text('Someone (probably via the console) created new conference New Con')
+    expect(page).to have_text('Someone (probably via the console) created new event type Talk in conference NewCon')
+    expect(page).to have_text('Someone (probably via the console) created new event type Workshop in conference NewCon')
+    expect(page).to have_text('Someone (probably via the console) updated title and short title of conference New Con')
+  end
+
+  scenario 'display changes in event_type', feature: true, versioning: true, js: true do
+    event_type = create(:event_type, program: conference.program, name: 'Discussion')
+    event_type.update_attributes(length: 90, maximum_abstract_length: 10000)
+    event_type.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) created new event type Discussion in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) updated length and maximum abstract length of event type Discussion in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) deleted event type Discussion in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in lodging', feature: true, versioning: true, js: true do
+    lodging = create(:lodging, conference: conference, name: 'Hotel XYZ')
+    lodging.update_attributes(description: 'Nice view,close to venue', website_link: 'http://www.example.com')
+    lodging.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) created new lodging Hotel XYZ in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) updated description and website link of lodging Hotel XYZ in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) deleted lodging Hotel XYZ in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in role', feature: true, versioning: true, js: true do
+    visit edit_admin_conference_role_path(conference.short_title, 'cfp')
+    fill_in 'role_description', with: 'For the members of the call for papers team'
+    click_button 'Update Role'
+
+    visit admin_revision_history_path(conference_id: conference.short_title)
+    expect(page).to have_text("#{organizer.name} updated description of role cfp in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in room', feature: true, versioning: true, js: true do
+    venue = create(:venue, conference: conference)
+    room = create(:room, venue: venue, name: 'Auditorium')
+    room.update_attributes(size: 120)
+    room.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) created new room Auditorium in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) updated size of room Auditorium in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) deleted room Auditorium in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in sponsor', feature: true, versioning: true, js: true do
+    conference.sponsorship_levels << create_list(:sponsorship_level, 2, conference: conference)
+    sponsor = create(:sponsor, conference: conference, name: 'SUSE', sponsorship_level: conference.sponsorship_levels.first)
+    sponsor.update_attributes(website_url: 'https://www.suse.com/company/history', sponsorship_level: conference.sponsorship_levels.second)
+    sponsor.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) created new sponsor SUSE in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) updated website url and sponsorship level of sponsor SUSE in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) deleted sponsor SUSE in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in sponsorship_level', feature: true, versioning: true, js: true do
+    sponsorship_level = create(:sponsorship_level, conference: conference)
+    sponsorship_level.update_attributes(title: 'Gold')
+    sponsorship_level.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) created new sponsorship level Gold in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) updated title of sponsorship level Gold in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) deleted sponsorship level Gold in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in ticket', feature: true, versioning: true, js: true do
+    ticket = create(:ticket, conference: conference, title: 'Gold')
+    ticket.update_attributes(price: 50, description: 'Premium Ticket')
+    ticket.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) created new ticket Gold in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) updated price cents and description of ticket Gold in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) deleted ticket Gold in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in track', feature: true, versioning: true, js: true do
+    track = create(:track, program: conference.program, name: 'Distribution')
+    track.update_attributes(description: 'Events about Linux distributions')
+    track.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) created new track Distribution in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) updated description of track Distribution in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) deleted track Distribution in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in venue', feature: true, versioning: true, js: true do
+    venue = create(:venue, conference: conference, name: 'Example University')
+    venue.update_attributes(website: 'www.example.com new', description: 'Just another beautiful venue')
+    venue.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) created new venue Example University in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) updated website and description of venue Example University in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) deleted venue Example University in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in event', feature: true, versioning: true, js: true do
+    visit new_conference_program_proposal_path(conference_id: conference.short_title)
+    fill_in 'event_title', with: 'ABC'
+    fill_in 'event_abstract', with: 'Lorem ipsum abstract'
+    select('Talk - 30 min', from: 'event[event_type_id]')
+    click_button 'Create Proposal'
+
+    click_link 'Edit'
+    fill_in 'event_subtitle', with: 'My event subtitle'
+    select('Easy', from: 'event[difficulty_level_id]')
+    click_button 'Update Proposal'
+
+    visit admin_conference_program_events_path(conference.short_title)
+    click_button 'New'
+    click_link 'Reject event'
+
+    visit conference_program_proposal_index_path(conference_id: conference.short_title)
+    click_link 'Re-Submit'
+
+    visit admin_conference_program_events_path(conference.short_title)
+    click_button 'New'
+    click_link 'Accept event'
+
+    visit conference_program_proposal_index_path(conference_id: conference.short_title)
+    click_link 'Confirm'
+
+    visit admin_conference_program_events_path(conference.short_title)
+    click_button 'Confirmed'
+    click_link 'Cancel event'
+
+    visit admin_revision_history_path
+    expect(page).to have_text("#{organizer.name} submitted new event ABC in conference #{conference.short_title}")
+    expect(page).to have_text("#{organizer.name} updated difficulty level and subtitle of event ABC in conference #{conference.short_title}")
+    expect(page).to have_text("#{organizer.name} rejected event ABC in conference #{conference.short_title}")
+    expect(page).to have_text("#{organizer.name} resubmitted event ABC in conference #{conference.short_title}")
+    expect(page).to have_text("#{organizer.name} accepted event ABC in conference #{conference.short_title}")
+    expect(page).to have_text("#{organizer.name} confirmed event ABC in conference #{conference.short_title}")
+    expect(page).to have_text("#{organizer.name} canceled event ABC in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in difficulty levels', feature: true, versioning: true, js: true do
+    difficulty_level = create(:difficulty_level, program: conference.program, title: 'Expert')
+    difficulty_level.update_attributes(description: 'Only for Experts')
+    difficulty_level.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) created new difficulty level Expert in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) updated description of difficulty level Expert in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) deleted difficulty level Expert in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in splashpages', feature: true, versioning: true, js: true do
+    visit admin_conference_splashpage_path(conference.short_title)
+    click_link 'Create Splashpage'
+    click_button 'Save Splashpage'
+
+    click_link 'Edit'
+    check('Make splash page public')
+    check('Display tracks on the splashpage?')
+    check('Display the registration period on the splashpage?')
+    click_button 'Save Splashpage'
+
+    click_link 'Delete'
+    visit admin_revision_history_path
+    expect(page).to have_text("#{organizer.name} created new splashpage in conference #{conference.short_title}")
+    expect(page).to have_text("#{organizer.name} updated public, include tracks and include registrations of splashpage in conference #{conference.short_title}")
+    expect(page).to have_text("#{organizer.name} deleted splashpage in conference #{conference.short_title}")
+  end
+
+  scenario 'displays users subscribe/unsubscribe to conferences', feature: true, versioning: true, js: true do
+    visit root_path
+    click_link 'Subscribe'
+    click_link 'Unsubscribe'
+    PaperTrail::Version.last.reify.save!
+    PaperTrail::Version.last.item.destroy!
+
+    visit admin_revision_history_path
+    expect(page).to have_text("#{organizer.name} subscribed to conference #{conference.title}")
+    expect(page).to have_text("#{organizer.name} unsubscribed from conference #{conference.title}")
+    expect(page).to have_text("Someone (probably via the console) subscribed #{organizer.name} to conference #{conference.title}")
+    expect(page).to have_text("Someone (probably via the console) unsubscribed #{organizer.name} from conference #{conference.title}")
+  end
+
+  scenario 'display changes in conference commercials', feature: true, versioning: true, js: true do
+    conference_commercial = create(:conference_commercial, commercialable: conference)
+    conference_commercial.update_attributes(url: 'https://www.youtube.com/watch?v=VNkDJk5_9eU')
+    conference_commercial.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) created new commercial in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) updated url of commercial in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) deleted commercial in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in event commercials', feature: true, versioning: true, js: true do
+    event = create(:event, program: conference.program)
+    event_commercial = create(:event_commercial, commercialable: event, url: 'https://www.youtube.com/watch?v=M9bq_alk-sw')
+    event_commercial.update_attributes(url: 'https://www.youtube.com/watch?v=VNkDJk5_9eU')
+    event_commercial.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) created new commercial in event #{event.title} in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) updated url of commercial in event #{event.title} in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) deleted commercial in event #{event.title} in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in users_role', feature: true, versioning: true, js: true do
+    user = create(:user)
+    user.add_role :cfp, conference
+    user.remove_role :cfp, conference
+
+    visit admin_revision_history_path
+    expect(page).to have_text("added role cfp to user #{user.name} in conference #{conference.short_title}")
+    expect(page).to have_text("removed role cfp from user #{user.name} in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in email settings', feature: true, versioning: true, js: true do
+    conference.email_settings.update_attributes(registration_subject: 'xxxxx', registration_body: 'yyyyy', accepted_subject: 'zzzzz')
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) updated registration subject, registration body and accepted subject
+    of email settings in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in conference registrations', feature: true, versioning: true, js: true do
+    Registration.create(user: organizer, conference: conference)
+    Registration.last.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) registered #{organizer.name} to conference #{conference.title}")
+    expect(page).to have_text("Someone (probably via the console) unregistered #{organizer.name} from conference #{conference.title}")
+  end
+
+  scenario 'display changes in event registration', feature: true, versioning: true, js: true do
+    registration = Registration.create(user: organizer, conference: conference)
+    event = create(:event, program: conference.program)
+    EventsRegistration.create(registration: registration, event: event)
+    EventsRegistration.first.update_attributes(attended: true)
+    EventsRegistration.last.destroy
+    # Here registration is deleted to ensure the event registration related change still displays the asociated user's name
+    registration.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) registered #{organizer.name} to event #{event.title} in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) updated attended of #{organizer.name}'s registration for event #{event.title} in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) unregistered #{organizer.name} from event #{event.title} in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in target', feature: true, versioning: true, js: true do
+    target = create(:target, conference: conference)
+    target.update_attributes(due_date: Date.today, target_count: 1000)
+    target.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) created new target 1000 Submissions by #{Date.today} in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) updated due date and target count of target 1000 Submissions by #{Date.today} in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) deleted target 1000 Submissions by #{Date.today} in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in comment', feature: true, versioning: true, js: true do
+    event = create(:event, program: conference.program)
+    visit admin_conference_program_event_path(conference_id: conference.short_title, id: event.id)
+    click_link 'Comments (0)'
+    fill_in 'comment_body', with: 'Sample comment'
+    click_button 'Add Comment'
+    Comment.last.destroy
+    PaperTrail::Version.last.reify.save
+
+    visit admin_revision_history_path
+    expect(page).to have_text("#{organizer.name} commented on event #{event.title} in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) deleted #{organizer.name}'s comment on event #{event.title} in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) re-added #{organizer.name}'s comment on event #{event.title}  in conference #{conference.short_title}")
+  end
+
+  scenario 'display changes in campaign', feature: true, versioning: true, js: true do
+    campaign = create(:campaign, conference: conference, name: 'Test Campaign', utm_campaign: 'campaign')
+    campaign.update_attributes(utm_source: 'source', utm_medium: 'medium', utm_term: 'term', utm_content: 'content')
+    campaign.destroy
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) created new campaign Test Campaign in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) updated utm source, utm medium, utm term and utm content of campaign Test Campaign in conference #{conference.short_title}")
+    expect(page).to have_text("Someone (probably via the console) deleted campaign Test Campaign in conference #{conference.short_title}")
+  end
+
+  scenario 'display password reset requests', feature: true, versioning: true, js: true do
+    user = create(:user)
+    user.send_reset_password_instructions
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone requested password reset of user #{user.name}")
+  end
+
+  scenario 'display user signups', feature: true, versioning: true, js: true do
+    create(:user, name: 'testname')
+
+    visit admin_revision_history_path
+    expect(page).to have_text('testname signed up')
+  end
+
+  scenario 'display updates to user', feature: true, versioning: true, js: true do
+    user = create(:user)
+    user.update_attributes(nickname: 'testnick', affiliation: 'openSUSE')
+
+    visit admin_revision_history_path
+    expect(page).to have_text("Someone (probably via the console) updated  nickname and affiliation of user #{user.name}")
+  end
+end