fix(champs.epci): epci names change over time. remap when it occurs

app/models/champs/epci_champ.rb

@@ -1,6 +1,7 @@
 class Champs::EpciChamp < Champs::TextChamp
   store_accessor :value_json, :code_departement, :code_region
   before_validation :on_departement_change
+  before_validation :on_epci_name_changes
 
   validate :code_departement_in_departement_codes, unless: -> { code_departement.nil? }
   validate :external_id_in_departement_epci_codes, unless: -> { code_departement.nil? || external_id.nil? }
@@ -99,4 +100,13 @@ class Champs::EpciChamp < Champs::TextChamp
 
     errors.add(:value, :not_in_departement_epci_names)
   end
+
+  def on_epci_name_changes
+    return if external_id.nil? || code_departement.nil?
+    return if value.in?(APIGeoService.epcis(code_departement).pluck(:name))
+
+    if external_id.in?(APIGeoService.epcis(code_departement).pluck(:code))
+      self.value = (external_id)
+    end
+  end
 end

spec/models/champs/epci_champ_spec.rb

@@ -110,10 +110,10 @@ describe Champs::EpciChamp, type: :model do
           it { is_expected.to be_valid }
         end
 
-        context 'when value is empty' do
+        context 'when value is in departement epci names' do
-          let(:value) { '' }
+          let(:value) { 'CA Haut - Bugey Agglomération' }
 
-          it { is_expected.not_to be_valid }
+          it { is_expected.to be_valid }
         end
 
         context 'when value is in departement epci names' do
@@ -122,10 +122,22 @@ describe Champs::EpciChamp, type: :model do
           it { is_expected.to be_valid }
         end
 
-        context 'when value is not in departement epci names' do
+        context 'when epci name had been renamed' do
           let(:value) { 'totoro' }
 
-          it { is_expected.not_to be_valid }
+          it 'is valid and updates its own value' do
+            expect(subject).to be_valid
+            expect(subject.value).to eq('CA Haut - Bugey Agglomération')
+          end
+        end
+
+        context 'when value is not in departement epci names nor in departement epci codes' do
+          let(:value) { 'totoro' }
+
+          it 'is invalid' do
+            allow(APIGeoService).to receive(:epcis).with(champ.code_departement).and_return([])
+            expect(subject).not_to be_valid
+          end
         end
       end
     end