feat(dossier): allow to rebase champs with value made mandatory

app/models/concerns/dossier_rebase_concern.rb

@@ -43,7 +43,7 @@ module DossierRebaseConcern
     when :drop_down_other
       !change[:from] && change[:to]
     when :mandatory
-      change[:from] && !change[:to]
+      (change[:from] && !change[:to]) || can_change_mandatory?(change)
     when :type_champ, :condition
       false
     else
@@ -160,4 +160,8 @@ module DossierRebaseConcern
   def purge_piece_justificative_file(champ)
     ActiveStorage::Attachment.where(id: champ.piece_justificative_file.ids).delete_all
   end
+
+  def can_change_mandatory?(change)
+    !champs.filter { _1.stable_id == change[:stable_id] }.any?(&:blank?)
+  end
 end

spec/models/dossier_rebase_concern_spec.rb

@@ -72,6 +72,17 @@ describe Dossier do
           expect(dossier.pending_changes).not_to be_empty
           expect(dossier.can_rebase?).to be_falsey
         end
+
+        context 'with a value' do
+          before do
+            dossier.champs.find_by(type_de_champ: type_de_champ).update(value: 'a value')
+          end
+
+          it 'should be true' do
+            expect(dossier.pending_changes).not_to be_empty
+            expect(dossier.can_rebase?).to be_truthy
+          end
+        end
       end
 
       context 'with type de champ change type' do