forbid admin merge yet

spec/controllers/manager/users_controller_spec.rb

@@ -30,6 +30,17 @@ describe Manager::UsersController, type: :controller do
 
           expect(User.find_by(id: user.id).email).to eq(nouvel_email)
         end
+
+        context 'and the user is an administrateur' do
+          let(:user) { create(:administrateur).user }
+
+          it 'rejects the modification' do
+            subject
+
+            expect(flash[:error]).to match("« nouvel.email@domaine.fr » est un administrateur. On ne sait pas encore faire.")
+            expect(user.reload.email).not_to eq(nouvel_email)
+          end
+        end
       end
 
       describe 'with an invalid email' do