diff --git a/app/lib/siade/etablissement_adapter.rb b/app/lib/siade/etablissement_adapter.rb
index ef03721b3..6b52d6bda 100644
--- a/app/lib/siade/etablissement_adapter.rb
+++ b/app/lib/siade/etablissement_adapter.rb
@@ -32,13 +32,9 @@ class SIADE::EtablissementAdapter
   end
 
   def adresse
-    adresse = ''
-    [:l1, :l2, :l3, :l4, :l5, :l6, :l7].each do |line|
-      if data_source[:etablissement][:adresse][line].present?
-        adresse = adresse + data_source[:etablissement][:adresse][line] + "\r\n"
-      end
-    end
-    adresse
+    [:l1, :l2, :l3, :l4, :l5, :l6, :l7].map do |line|
+      data_source[:etablissement][:adresse][line]
+    end.compact.join("\r\n")
   end
 
   def address_attribut_to_fetch
diff --git a/app/models/commentaire.rb b/app/models/commentaire.rb
index 7b3c651d9..3cfeab1da 100644
--- a/app/models/commentaire.rb
+++ b/app/models/commentaire.rb
@@ -14,7 +14,7 @@ class Commentaire < ActiveRecord::Base
   after_create :notify
 
   def header
-    "#{email}, " + I18n.l(created_at.localtime, format: '%d %b %Y %H:%M')
+    "#{email}, #{I18n.l(created_at.localtime, format: '%d %b %Y %H:%M')}"
   end
 
   def file_url
diff --git a/app/models/dossier.rb b/app/models/dossier.rb
index 5843337d2..a1dd384e1 100644
--- a/app/models/dossier.rb
+++ b/app/models/dossier.rb
@@ -154,12 +154,9 @@ class Dossier < ActiveRecord::Base
   end
 
   def convert_specific_hash_values_to_string(hash_to_convert)
-    hash = {}
-    hash_to_convert.each do |key, value|
-      value = serialize_value_for_export(value)
-      hash.store(key, value)
+    hash_to_convert.transform_values do |value|
+      serialize_value_for_export(value)
     end
-    hash
   end
 
   def full_data_strings_array
@@ -170,11 +167,11 @@ class Dossier < ActiveRecord::Base
 
   def export_entreprise_data
     if entreprise.present?
-      etablissement_attr = EtablissementCsvSerializer.new(self.etablissement).attributes.map { |k, v| ["etablissement.#{k}".parameterize.underscore.to_sym, v] }.to_h
-      entreprise_attr = EntrepriseSerializer.new(self.entreprise).attributes.map { |k, v| ["entreprise.#{k}".parameterize.underscore.to_sym, v] }.to_h
+      etablissement_attr = EtablissementCsvSerializer.new(self.etablissement).attributes.transform_keys { |k| "etablissement.#{k}".parameterize.underscore.to_sym }
+      entreprise_attr = EntrepriseSerializer.new(self.entreprise).attributes.transform_keys { |k| "entreprise.#{k}".parameterize.underscore.to_sym }
     else
-      etablissement_attr = EtablissementSerializer.new(Etablissement.new).attributes.map { |k, v| ["etablissement.#{k}".parameterize.underscore.to_sym, v] }.to_h
-      entreprise_attr = EntrepriseSerializer.new(Entreprise.new).attributes.map { |k, v| ["entreprise.#{k}".parameterize.underscore.to_sym, v] }.to_h
+      etablissement_attr = EtablissementSerializer.new(Etablissement.new).attributes.transform_keys { |k| "etablissement.#{k}".parameterize.underscore.to_sym }
+      entreprise_attr = EntrepriseSerializer.new(Entreprise.new).attributes.transform_keys { |k| "entreprise.#{k}".parameterize.underscore.to_sym }
     end
     convert_specific_hash_values_to_string(etablissement_attr.merge(entreprise_attr))
   end
diff --git a/app/models/gestionnaire.rb b/app/models/gestionnaire.rb
index 02cd33e81..1b965373a 100644
--- a/app/models/gestionnaire.rb
+++ b/app/models/gestionnaire.rb
@@ -55,8 +55,8 @@ class Gestionnaire < ActiveRecord::Base
     procedure_ids = followed_dossiers.pluck(:procedure_id)
 
     if procedure_ids.include?(procedure.id)
-      return followed_dossiers.where(procedure_id: procedure.id).inject(0) do |acc, dossier|
-        acc += dossier.notifications.where(already_read: false).count
+      return followed_dossiers.where(procedure_id: procedure.id).sum do |dossier|
+        dossier.notifications.where(already_read: false).count
       end
     end
     0
diff --git a/app/services/render_partial_service.rb b/app/services/render_partial_service.rb
index 5d37024ea..186c8f633 100644
--- a/app/services/render_partial_service.rb
+++ b/app/services/render_partial_service.rb
@@ -23,11 +23,11 @@ class RenderPartialService
   private
 
   def retrieve_navbar
-    'layouts/navbars/navbar_' + retrieve_name
+    "layouts/navbars/navbar_#{retrieve_name}"
   end
 
   def retrieve_left_panel
-    'layouts/left_panels/left_panel_' + retrieve_name
+    "layouts/left_panels/left_panel_#{retrieve_name}"
   end
 
   def retrieve_name
diff --git a/spec/controllers/users/description_controller_shared_example.rb b/spec/controllers/users/description_controller_shared_example.rb
index 0811a33e4..4a5d57e85 100644
--- a/spec/controllers/users/description_controller_shared_example.rb
+++ b/spec/controllers/users/description_controller_shared_example.rb
@@ -302,8 +302,8 @@ shared_examples 'description_controller_spec' do
       before do
         post :update, params: {
           dossier_id: dossier_id,
-          'piece_justificative_' + all_pj_type[0].to_s => piece_justificative_0,
-          'piece_justificative_' + all_pj_type[1].to_s => piece_justificative_1
+          "piece_justificative_#{all_pj_type[0].to_s}" => piece_justificative_0,
+          "piece_justificative_#{all_pj_type[1].to_s}" => piece_justificative_1
         }
         dossier.reload
       end
@@ -314,8 +314,8 @@ shared_examples 'description_controller_spec' do
 
           post :update, params: {
             dossier_id: dossier_id,
-            'piece_justificative_' + all_pj_type[0].to_s => piece_justificative_0,
-            'piece_justificative_' + all_pj_type[1].to_s => piece_justificative_1
+            "piece_justificative_#{all_pj_type[0].to_s}" => piece_justificative_0,
+            "piece_justificative_#{all_pj_type[1].to_s}" => piece_justificative_1
           }
         end
       end
@@ -355,8 +355,8 @@ shared_examples 'description_controller_spec' do
     subject {
       patch :pieces_justificatives, params: {
         dossier_id: dossier.id,
-        'piece_justificative_' + all_pj_type[0].to_s => piece_justificative_0,
-        'piece_justificative_' + all_pj_type[1].to_s => piece_justificative_1
+        "piece_justificative_#{all_pj_type[0].to_s}" => piece_justificative_0,
+        "piece_justificative_#{all_pj_type[1].to_s}" => piece_justificative_1
       }
     }
 
@@ -434,8 +434,8 @@ shared_examples 'description_controller_spec_POST_piece_justificatives_for_owner
   subject {
     patch :pieces_justificatives, params: {
       dossier_id: dossier.id,
-      'piece_justificative_' + all_pj_type[0].to_s => piece_justificative_0,
-      'piece_justificative_' + all_pj_type[1].to_s => piece_justificative_1
+      "piece_justificative_#{all_pj_type[0].to_s}" => piece_justificative_0,
+      "piece_justificative_#{all_pj_type[1].to_s}" => piece_justificative_1
     }
   }
 
diff --git a/spec/features/description_page/upload_piece_justificative_spec.rb b/spec/features/description_page/upload_piece_justificative_spec.rb
index 25ccf4f75..50f00c9fb 100644
--- a/spec/features/description_page/upload_piece_justificative_spec.rb
+++ b/spec/features/description_page/upload_piece_justificative_spec.rb
@@ -44,7 +44,7 @@ feature 'user is on description page' do
     end
     context 'when he adds a piece_justificative and submit form', vcr: { cassette_name: 'description_page_upload_piece_justificative_adds_cerfa_and_submit' } do
       before do
-        file_input_id = 'piece_justificative_' + dossier.types_de_piece_justificative.first.id.to_s
+        file_input_id = "piece_justificative_#{dossier.types_de_piece_justificative.first.id.to_s}"
         attach_file(file_input_id, File.path('spec/support/files/dossierPDF.pdf'))
         click_on('Soumettre mon dossier')
         dossier.reload
diff --git a/spec/features/users/dossier_edition_spec.rb b/spec/features/users/dossier_edition_spec.rb
index d64311de5..3de44ef52 100644
--- a/spec/features/users/dossier_edition_spec.rb
+++ b/spec/features/users/dossier_edition_spec.rb
@@ -21,7 +21,7 @@ feature 'As a User I want to edit a dossier I own' do
     end
 
     scenario 'Getting a dossier, I want to create a new message on', js: true do
-      page.find_by_id('tr_dossier_' + dossier.id.to_s).click
+      page.find_by_id("tr_dossier_#{dossier.id.to_s}").click
       expect(page).to have_current_path(users_dossier_recapitulatif_path(Dossier.first.id.to_s))
       page.find_by_id('open-message').click
       page.execute_script("$('#texte_commentaire').data('wysihtml5').editor.setValue('Contenu du nouveau message')")
@@ -30,7 +30,7 @@ feature 'As a User I want to edit a dossier I own' do
     end
 
     scenario 'On the same dossier, I want to edit informations', js: true do
-      page.find_by_id('tr_dossier_' + dossier.id.to_s).click
+      page.find_by_id("tr_dossier_#{dossier.id.to_s}").click
       expect(page).to have_current_path(users_dossier_recapitulatif_path(dossier.id.to_s))
 
       # Linked Dossier
diff --git a/spec/lib/siade/etablissement_adapter_spec.rb b/spec/lib/siade/etablissement_adapter_spec.rb
index 394f2ee70..3e5092692 100644
--- a/spec/lib/siade/etablissement_adapter_spec.rb
+++ b/spec/lib/siade/etablissement_adapter_spec.rb
@@ -33,7 +33,7 @@ describe SIADE::EtablissementAdapter do
 
       context 'Concaténation lignes adresse' do
         it 'L\'entreprise contient bien une adresse sur plusieurs lignes' do
-          expect(subject[:adresse]).to eq("OCTO TECHNOLOGY\r\n50 AVENUE DES CHAMPS ELYSEES\r\n75008 PARIS\r\nFRANCE\r\n")
+          expect(subject[:adresse]).to eq("OCTO TECHNOLOGY\r\n50 AVENUE DES CHAMPS ELYSEES\r\n75008 PARIS\r\nFRANCE")
         end
       end
 
diff --git a/spec/models/gestionnaire_spec.rb b/spec/models/gestionnaire_spec.rb
index e300ffe6c..7b92dd830 100644
--- a/spec/models/gestionnaire_spec.rb
+++ b/spec/models/gestionnaire_spec.rb
@@ -95,7 +95,7 @@ describe Gestionnaire, type: :model do
       it { is_expected.to eq 0 }
       it { expect(gestionnaire.follows.count).to eq 0 }
       it do
-        expect_any_instance_of(Dossier::ActiveRecord_AssociationRelation).not_to receive(:inject)
+        expect_any_instance_of(Dossier::ActiveRecord_AssociationRelation).not_to receive(:sum)
         subject
       end
     end
@@ -108,7 +108,7 @@ describe Gestionnaire, type: :model do
       it { is_expected.to eq 0 }
       it { expect(gestionnaire.follows.count).to eq 1 }
       it do
-        expect_any_instance_of(Dossier::ActiveRecord_AssociationRelation).not_to receive(:inject)
+        expect_any_instance_of(Dossier::ActiveRecord_AssociationRelation).not_to receive(:sum)
         subject
       end
     end
@@ -124,7 +124,7 @@ describe Gestionnaire, type: :model do
       it { is_expected.to eq 1 }
       it { expect(gestionnaire.follows.count).to eq 1 }
       it do
-        expect_any_instance_of(Dossier::ActiveRecord_AssociationRelation).to receive(:inject)
+        expect_any_instance_of(Dossier::ActiveRecord_AssociationRelation).to receive(:sum)
         subject
       end
     end