models: require belong_to associations on invite

app/models/invite.rb

@@ -14,7 +14,7 @@
 class Invite < ApplicationRecord
   include EmailSanitizableConcern
 
-  belongs_to :dossier
+  belongs_to :dossier, optional: false
   belongs_to :user, optional: true
 
   before_validation -> { sanitize_email(:email) }

spec/factories/invite.rb

@@ -1,24 +1,17 @@
 FactoryBot.define do
   factory :invite do
     email { 'plop@octo.com' }
+    user { nil }
+    association :dossier
 
     after(:build) do |invite, _evaluator|
-      if invite.dossier.nil?
-        invite.dossier = create(:dossier)
-      end
-
       if invite.user.present?
         invite.email = invite.user.email
       end
     end
 
     trait :with_user do
-      after(:build) do |invite, _evaluator|
-        if invite.user.nil?
-          invite.user = create(:user)
-          invite.email = invite.user.email
-        end
-      end
+      association :user
     end
   end
 end