feat: railtie to set Rails::Dom::Testing.default_html_version

based on Rails' config.dom_testing_default_html_version

Author: flavorjones

lib/rails/dom/testing/parser_selection.rb

@@ -47,3 +47,5 @@ def choose_html_parser(parser_classes, html_version: nil)
     end
   end
 end
+
+require_relative "railtie" if defined?(Rails::Railtie)

lib/rails/dom/testing/railtie.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module Rails
+  module Dom
+    module Testing
+      class Railtie < Rails::Railtie # :nodoc:
+        initializer "rails_dom_testing.default_html_version" do |app|
+          version = app.config.try(:dom_testing_default_html_version) # Rails 7.1+
+          Rails::Dom::Testing.default_html_version = version if version
+        end
+      end
+    end
+  end
+end