Why default_url_options is not working?

default_url_options.rb

# frozen_string_literal: true

require "bundler/inline"
require "json"

gemfile(true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  # Activate the gem you are reporting the issue against.
  gem "rails", "~> 7.0.0"
end

require "action_controller/railtie"

class TestApp < Rails::Application
  config.root = __dir__
  config.hosts << "example.org"
  secrets.secret_key_base = "secret_key_base"

  config.logger = Logger.new($stdout)
  Rails.logger  = config.logger

  routes.draw do
    get "/" => "test#index"
    post "/" => "test#update"
  end
end

class TestController < ActionController::Base
  include Rails.application.routes.url_helpers

  def default_url_options
    { "default_param" => "tenderlove" }
  end

  def index
    render json: params
  end

  def update
    # Rails.logger.warn(params)

    render json: params
  end

end

require "minitest/autorun"
require "rack/test"

class BugTest < Minitest::Test
  include Rack::Test::Methods

  def test_index
    get "/?foo=bar"

    hash_expected = {"foo"=>"bar", "controller"=>"test", "action"=>"index", "default_param" => "tenderlove"}

    assert_equal hash_expected, JSON.parse(last_response.body)
  end

  def test_update
    post("/", { foo: "baz" })

    hash_expect = {"foo"=>"bar", "controller"=>"test", "action"=>"index", "default_param" => "tenderlove"}

    assert_equal hash_expect, JSON.parse(last_response.body)
  end

  private
    def app
      Rails.application
    end
end