Add audit log to registrant verifications

Closes #1425

test/tasks/data_migrations/delete_orphaned_registrant_verifications_test.rb

@@ -0,0 +1,43 @@
+require 'test_helper'
+
+class ArchiveOrphanedRegistrantVerificationsTest < ActiveSupport::TestCase
+  def test_deletes_orphaned_registrant_verifications
+    create_orphaned_registrant_verification
+
+    assert_difference 'RegistrantVerification.count', -1 do
+      capture_io do
+        run_task
+      end
+    end
+  end
+
+  def test_keeps_non_orphaned_registrant_verifications_intact
+    assert_no_difference 'RegistrantVerification.count' do
+      capture_io do
+        run_task
+      end
+    end
+  end
+
+  def test_output
+    create_orphaned_registrant_verification
+
+    assert_output "Processed: 1 out of 1\n" do
+      run_task
+    end
+  end
+
+  private
+
+  def create_orphaned_registrant_verification
+    non_existent_domain_id = 55
+    assert_not_includes Domain.ids, non_existent_domain_id
+
+    RegistrantVerification.connection.disable_referential_integrity do
+      registrant_verifications(:one).update_columns(domain_id: non_existent_domain_id)
+    end
+  end
+
+  def run_task
+    Rake::Task['data_migrations:delete_orphaned_registrant_verifications'].execute end
+end