Example for issue #32083

rails-32083.rb

# frozen_string_literal: true

begin
  require "bundler/inline"
rescue LoadError => e
  $stderr.puts "Bundler version 1.10 or later is required. Please update your Bundler"
  raise e
end

gemfile(true) do
  source "https://rubygems.org"
  gem "rails", "5.1.5"
end

require "rack/test"
require "action_controller/railtie"

class TestApp < Rails::Application
  config.root = __dir__
  config.session_store :cookie_store, key: "cookie_store_key"
  secrets.secret_key_base = "secret_key_base"

  config.logger = Logger.new("/dev/null")
  Rails.logger  = config.logger

  routes.draw do
    get "/*id", to: "pages#show", id: /(?!admin).*/
  end
end

class ApplicationController < ActionController::Base
  include Rails.application.routes.url_helpers
end

class PagesController < ApplicationController
  def show
    render plain: request.path
  end
end

require "minitest/autorun"

# Ensure backward compatibility with Minitest 4
Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)

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

  def test_negative_lookup_constraints
    get "/foo"
    assert_equal 200, last_response.status
    assert_equal "/foo", last_response.body

    get "/foo/admin"
    assert_equal 200, last_response.status
    assert_equal "/foo/admin", last_response.body

    get "/admin"
    assert_equal 404, last_response.status

    get "/admin/foo"
    assert_equal 404, last_response.status
  end

  private

  def app
    Rails.application
  end
end