Maintenance: Add tests for notification template rendering.

spec/lib/notification_factory/renderer/notification_templates_spec.rb

@@ -0,0 +1,35 @@
+# Copyright (C) 2012-2024 Zammad Foundation, https://zammad-foundation.org/
+
+require 'rails_helper'
+
+RSpec.describe 'NotificationFactory::Renderer > Notification Templates' do # rubocop:disable RSpec/DescribeClass
+
+  matcher :render_without_errors do
+    match do
+      NotificationFactory::Renderer.new(
+        objects:  { changes: { field: 'value' }, article:, ticket:, recipient:, current_user: },
+        template: actual.read,
+        trusted:  true,
+      ).render
+    rescue => e
+      @error = e
+      false
+    end
+
+    failure_message do
+      "Expected #{actual.relative_path_from(Rails.root)} to render without errors, but it failed with error: #{@error}"
+    end
+  end
+
+  # Cache the objects to speed the tests up.
+  let(:current_user) { create(:agent) }
+  let(:recipient)    { create(:customer) }
+  let(:ticket)       { create(:ticket) }
+  let(:article)      { create(:ticket_article, ticket:) }
+
+  it 'renders English and translated notification templates without syntax errors', :aggregate_failures do
+    Rails.root.join('app/views').glob('{mailer,messaging}/*/*.erb').each do |file| # rubocop:disable RSpec/IteratedExpectation
+      expect(file).to render_without_errors
+    end
+  end
+end