Add coverage for model normalizations (#31734)

spec/models/account_spec.rb

@@ -723,14 +723,15 @@ RSpec.describe Account do
     end
   end
 
+  describe 'Normalizations' do
+    describe 'username' do
+      it { is_expected.to normalize(:username).from(" \u3000bob \t \u00a0 \n ").to('bob') }
+    end
+  end
+
   describe 'validations' do
     it { is_expected.to validate_presence_of(:username) }
 
-    it 'squishes the username before validation' do
-      account = Fabricate(:account, domain: nil, username: " \u3000bob \t \u00a0 \n ")
-      expect(account.username).to eq 'bob'
-    end
-
     context 'when is local' do
       it 'is invalid if the username is not unique in case-insensitive comparison among local accounts' do
         _account = Fabricate(:account, username: 'the_doctor')