improve test setup with factory bot

spec/factories/user_documents.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: user_documents
+#
+#  id         :bigint           not null, primary key
+#  status     :string           not null
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#  user_id    :bigint           not null
+#
+# Indexes
+#
+#  index_user_documents_on_user_id  (user_id)
+#
+# Foreign Keys
+#
+#  fk_rails_...  (user_id => users.id)
+#
+FactoryBot.define do
+  factory :user_document do
+    association :user
+    status { :pending_review }
+  end
+end