Add coverage for title/limit validations in List model (#31869)

spec/models/list_spec.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe List do
+  describe 'Validations' do
+    subject { Fabricate.build :list }
+
+    it { is_expected.to validate_presence_of(:title) }
+
+    context 'when account has hit max list limit' do
+      let(:account) { Fabricate :account }
+
+      before { stub_const 'List::PER_ACCOUNT_LIMIT', 0 }
+
+      context 'when creating a new list' do
+        it { is_expected.to_not allow_value(account).for(:account).against(:base).with_message(I18n.t('lists.errors.limit')) }
+      end
+
+      context 'when updating an existing list' do
+        before { subject.save(validate: false) }
+
+        it { is_expected.to allow_value(account).for(:account).against(:base) }
+      end
+    end
+  end
+end