diff --git a/Gemfile.lock b/Gemfile.lock
index 539a201e..4eb23f40 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -249,7 +249,7 @@ GEM
       thor (>= 0.14, < 2.0)
     jquery-ui-rails (4.2.1)
       railties (>= 3.2.16)
-    json (2.2.0)
+    json (2.3.0)
     json-schema (2.8.1)
       addressable (>= 2.4)
     jsonapi-renderer (0.2.2)
@@ -302,7 +302,7 @@ GEM
     nenv (0.3.0)
     netrc (0.11.0)
     nio4r (2.5.2)
-    nokogiri (1.10.5)
+    nokogiri (1.10.8)
       mini_portile2 (~> 2.4.0)
     notiffany (0.1.1)
       nenv (~> 0.1)
@@ -372,7 +372,7 @@ GEM
       method_source (~> 0.8.1)
       slop (~> 3.4)
     public_suffix (3.1.1)
-    puma (3.12.2)
+    puma (3.12.4)
     rack (2.0.8)
     rack-openid (1.3.1)
       rack (>= 1.1.0)
@@ -547,7 +547,7 @@ GEM
       actionpack (>= 4.0)
       activesupport (>= 4.0)
       sprockets (>= 3.0.0)
-    sqlite3 (1.4.1)
+    sqlite3 (1.4.2)
     stripe (5.14.0)
     stripe-ruby-mock (3.0.1)
       dante (>= 0.2.0)
diff --git a/app/models/vote.rb b/app/models/vote.rb
index 2ce0e671..64ab74de 100644
--- a/app/models/vote.rb
+++ b/app/models/vote.rb
@@ -4,6 +4,8 @@ class Vote < ApplicationRecord
   belongs_to :user
   belongs_to :event
 
+  validates :user_id, uniqueness: { scope: :event_id }
+
   has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
 
   delegate :name, to: :user
diff --git a/spec/controllers/admin/roles_controller_spec.rb b/spec/controllers/admin/roles_controller_spec.rb
index 6a0d7754..cd5cdc1c 100644
--- a/spec/controllers/admin/roles_controller_spec.rb
+++ b/spec/controllers/admin/roles_controller_spec.rb
@@ -91,7 +91,7 @@ describe Admin::RolesController do
                                      user:          { email: 'user1@osem.io' },
                                      id:            'organizer' }
 
-        expect(user1.roles).to eq [organizer_role, cfp_role]
+        expect(user1.roles).to contain_exactly(cfp_role, organizer_role)
       end
     end
 
@@ -109,7 +109,7 @@ describe Admin::RolesController do
                                      user:          { email: 'user1@osem.io' },
                                      id:            'organizer' }
 
-        expect(user1.roles).to eq [organizer_role, cfp_role]
+        expect(user1.roles).to contain_exactly(cfp_role, organizer_role)
 
         post :toggle_user, params: { conference_id: conference.short_title,
                                      user:          { email: 'user1@osem.io', state: 'false' },
diff --git a/spec/controllers/admin/versions_controller_spec.rb b/spec/controllers/admin/versions_controller_spec.rb
index 8c453efd..69e3d362 100644
--- a/spec/controllers/admin/versions_controller_spec.rb
+++ b/spec/controllers/admin/versions_controller_spec.rb
@@ -18,7 +18,7 @@ describe Admin::VersionsController do
 
       it 'reverts all changes for update actions' do
         conference.update_attributes(short_title: 'testtitle', description: 'Some random text')
-        get :revert_object, params: { id: PaperTrail::Version.last.id }
+        get :revert_object, params: { id: conference.versions.last.id }
         conference.reload
         expect(conference.short_title).to eq 'exampletitle'
         expect(conference.description).to eq 'Example Description'
@@ -32,18 +32,19 @@ describe Admin::VersionsController do
       end
 
       it 'reverting deletion of object  creates it again' do
-        conference.program.event_types.first.destroy
+        event_type = conference.program.event_types.first
+        event_type.destroy
         event_types_count = conference.program.event_types.count
-        get :revert_object, params: { id: PaperTrail::Version.last.id }
+        get :revert_object, params: { id: event_type.versions.last.id }
         conference.reload
-        expect(PaperTrail::Version.last.event).to eq 'create'
+        expect(event_type.versions.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, params: { id: PaperTrail::Version.last.id }
-        expect(PaperTrail::Version.last.event).to eq 'destroy'
+        lodging = create(:lodging, conference: conference)
+        get :revert_object, params: { id: lodging.versions.last.id }
+        expect(lodging.versions.last.event).to eq 'destroy'
         expect(Lodging.count).to eq 0
       end
 
@@ -62,7 +63,7 @@ describe Admin::VersionsController do
 
       it 'reverts specified change for update actions' do
         conference.update_attributes(short_title: 'testtitle', description: 'Some random text')
-        get :revert_attribute, params: { id: PaperTrail::Version.last.id, attribute: 'short_title' }
+        get :revert_attribute, params: { id: conference.versions.last.id, attribute: 'short_title' }
         conference.reload
         expect(conference.short_title).to eq 'exampletitle'
         expect(conference.description).to eq 'Some random text'
@@ -71,22 +72,23 @@ describe Admin::VersionsController do
       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, params: { id: PaperTrail::Version.all[-2].id, attribute: 'short_title' }
+        get :revert_attribute, params: { id: conference.versions[-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, params: { id: PaperTrail::Version.all[-2].id, attribute: 'title' }
+        event_type = conference.program.event_types.first
+        event_type.update_attributes(title: 'New Event Title')
+        event_type.destroy
+        get :revert_attribute, params: { id: event_type.versions[-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, params: { id: PaperTrail::Version.last.id, attribute: 'name' }
+        lodging = create(:lodging, conference: conference)
+        get :revert_attribute, params: { id: lodging.versions.last.id, attribute: 'name' }
         expect(flash[:alert]).to eq 'You are not authorized to access this page.'
       end
 
@@ -94,7 +96,7 @@ describe Admin::VersionsController 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, params: { id: PaperTrail::Version.last.id, attribute: 'title' }
+        get :revert_attribute, params: { id: conference.versions.last.id, attribute: 'title' }
         conference.reload
         expect(conference.short_title).to eq 'testtitle'
         expect(conference.description).to eq 'Some random text'
@@ -116,12 +118,12 @@ describe Admin::VersionsController do
           @user = create(:user)
 
           conference.update_attributes(short_title: 'testtitle', description: 'Some random text')
-          @version_organizer = PaperTrail::Version.last
-          create(:cfp, program: conference.program)
-          @version_cfp = PaperTrail::Version.last
+          @version_organizer = conference.versions.last
+          cfp = create(:cfp, program: conference.program)
+          @version_cfp = cfp.versions.last
           registration = create(:registration, conference: conference)
           registration.update_attributes(attended: true)
-          @version_info_desk = PaperTrail::Version.last
+          @version_info_desk = registration.versions.last
         end
 
         it 'when user has role cfp' do
diff --git a/spec/controllers/api/v1/conferences_controller_spec.rb b/spec/controllers/api/v1/conferences_controller_spec.rb
index b126d87d..fc82fdc3 100644
--- a/spec/controllers/api/v1/conferences_controller_spec.rb
+++ b/spec/controllers/api/v1/conferences_controller_spec.rb
@@ -21,8 +21,7 @@ describe Api::V1::ConferencesController do
     end
 
     it 'returns correct conferences' do
-      expect(@json[0]['short_title']).to eq('conf_one')
-      expect(@json[1]['short_title']).to eq('conf_two')
+      expect(@json.pluck('short_title')).to contain_exactly('conf_one', 'conf_two')
     end
   end
 
diff --git a/spec/controllers/api/v1/events_controller_spec.rb b/spec/controllers/api/v1/events_controller_spec.rb
index 1f9b2809..845cb5b0 100644
--- a/spec/controllers/api/v1/events_controller_spec.rb
+++ b/spec/controllers/api/v1/events_controller_spec.rb
@@ -15,9 +15,7 @@ describe Api::V1::EventsController do
         json = JSON.parse(response.body)['events']
         expect(response).to be_success
 
-        expect(json.length).to eq(2)
-        expect(json[0]['title']).to eq('Example Event')
-        expect(json[1]['title']).to eq('Conference Event')
+        expect(json.pluck('title')).to contain_exactly('Conference Event', 'Example Event')
       end
     end
 
diff --git a/spec/controllers/api/v1/rooms_controller_spec.rb b/spec/controllers/api/v1/rooms_controller_spec.rb
index f8262800..00b927e9 100644
--- a/spec/controllers/api/v1/rooms_controller_spec.rb
+++ b/spec/controllers/api/v1/rooms_controller_spec.rb
@@ -17,9 +17,7 @@ describe Api::V1::RoomsController do
 
         expect(response).to be_success
 
-        expect(json.length).to eq(2)
-        expect(json[0]['name']).to eq('Conference Room')
-        expect(json[1]['name']).to eq('Test Room')
+        expect(json.pluck('name')).to contain_exactly('Conference Room', 'Test Room')
       end
     end
 
diff --git a/spec/controllers/api/v1/speakers_controller_spec.rb b/spec/controllers/api/v1/speakers_controller_spec.rb
index fdaa08a0..d29ddfb3 100644
--- a/spec/controllers/api/v1/speakers_controller_spec.rb
+++ b/spec/controllers/api/v1/speakers_controller_spec.rb
@@ -22,9 +22,7 @@ describe Api::V1::SpeakersController do
         get :index, params: { format: :json }
         json = JSON.parse(response.body)['speakers']
         expect(response).to be_success
-        expect(json.length).to eq(2)
-        expect(json[0]['name']).to eq('Speaker')
-        expect(json[1]['name']).to eq('Conf_Speaker')
+        expect(json.pluck('name')).to contain_exactly('Conf_Speaker', 'Speaker')
       end
     end
 
diff --git a/spec/controllers/api/v1/tracks_controller_spec.rb b/spec/controllers/api/v1/tracks_controller_spec.rb
index 65346b56..f8b0b53a 100644
--- a/spec/controllers/api/v1/tracks_controller_spec.rb
+++ b/spec/controllers/api/v1/tracks_controller_spec.rb
@@ -16,9 +16,7 @@ describe Api::V1::TracksController do
 
         expect(response).to be_success
 
-        expect(json.length).to eq(2)
-        expect(json[0]['name']).to eq('Conference Track')
-        expect(json[1]['name']).to eq('Test Track')
+        expect(json.pluck('name')).to contain_exactly('Conference Track', 'Test Track')
       end
     end
 
diff --git a/spec/features/roles_spec.rb b/spec/features/roles_spec.rb
index 723b41c0..b08e0398 100644
--- a/spec/features/roles_spec.rb
+++ b/spec/features/roles_spec.rb
@@ -66,7 +66,7 @@ feature Role do
     scenario "removes role #{role_name}", feature: true, js: true do
       click_link('Users', href: admin_conference_role_path(conference.short_title, role_name))
 
-      bootstrap_switch = first('td').find('.bootstrap-switch-container')
+      bootstrap_switch = find('tr', text: user_with_role.name).find('.bootstrap-switch-container')
       bootstrap_switch.click
 
       expect(page).to have_css('.alert', text: "Successfully removed role #{role_name} from user #{user_with_role.email}")
diff --git a/spec/models/vote_spec.rb b/spec/models/vote_spec.rb
new file mode 100644
index 00000000..39afb352
--- /dev/null
+++ b/spec/models/vote_spec.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Vote do
+  let!(:vote) { create(:vote) }
+
+  describe 'validation' do
+    it 'has a valid factory' do
+      expect(build(:vote)).to be_valid
+    end
+
+    it { is_expected.to validate_uniqueness_of(:user_id).scoped_to(:event_id) }
+
+    # This is testing the relationship instead of using the shoulda-matchers
+    context 'vote with user already exists' do
+      it 'fails when adding vote twice for user and event' do
+        expect { create(:vote, user: vote.user, event: vote.event) }
+          .to raise_error(ActiveRecord::RecordInvalid, 'Validation failed: User has already been taken')
+      end
+    end
+  end
+end