fix(dossier): do not attempt to destroy transfers when a dossier is destroyed

we had a dependent option on both sides of a relationship which created race conditions

app/models/dossier.rb

@@ -124,7 +124,7 @@ class Dossier < ApplicationRecord
   has_many :types_de_champ, through: :revision
   has_many :types_de_champ_private, through: :revision
 
-  belongs_to :transfer, class_name: 'DossierTransfer', foreign_key: 'dossier_transfer_id', optional: true, inverse_of: :dossiers, dependent: :destroy
+  belongs_to :transfer, class_name: 'DossierTransfer', foreign_key: 'dossier_transfer_id', optional: true, inverse_of: :dossiers
   has_many :transfer_logs, class_name: 'DossierTransferLog', dependent: :destroy
 
   accepts_nested_attributes_for :champs

spec/factories/dossier_transfer.rb

@@ -0,0 +1,5 @@
+FactoryBot.define do
+  factory :dossier_transfer do
+    email { generate(:user_email) }
+  end
+end

spec/models/dossier_spec.rb

@@ -1439,14 +1439,18 @@ describe Dossier do
   end
 
   describe "#destroy" do
-    let(:dossier) { create(:dossier) }
+    let(:transfer) { create(:dossier_transfer) }
+    let(:dossier) { create(:dossier, transfer: transfer) }
+
     before do
+      create(:dossier, transfer: transfer)
       create(:attestation, dossier: dossier)
       create(:attestation, dossier: dossier)
     end
 
     it "can destroy dossier with two attestations" do
       expect(dossier.destroy).to be_truthy
+      expect(transfer.reload).not_to be_nil
     end
   end
 

spec/models/dossier_transfer_spec.rb

@@ -46,5 +46,16 @@ RSpec.describe DossierTransfer, type: :model do
         it { expect(DossierTransfer.with_dossiers.count).to eq(0) }
       end
     end
+
+    describe 'dossier relationship' do
+      let(:transfer) { create(:dossier_transfer) }
+      let(:dossier) { create(:dossier, user: user, transfer: transfer) }
+
+      it 'nullify transfer relationship on dossier' do
+        expect(dossier.transfer).to eq(transfer)
+        transfer.destroy
+        expect(dossier.reload.transfer).to be_nil
+      end
+    end
   end
 end