Add coverage for model normalizations (#31734)

spec/models/relay_spec.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Relay do
+  describe 'Normalizations' do
+    describe 'inbox_url' do
+      it { is_expected.to normalize(:inbox_url).from('  http://host.example  ').to('http://host.example') }
+    end
+  end
+end