Base test for ensuring all controller actions that take an ID will throw a RecordNotFound for invalid IDs

gistfile1.rb

class BaseTest < ActionDispatch::IntegrationTest
    test "all controllers should raise exceptions with invalid IDs" do
      routes = Rails.application.routes.routes
      id_based_routes = routes.find_all { |r| r.required_parts.include?(:id) }
      id_based_routes.each do |route|
        klass = "#{route.defaults[:controller]}_controller".classify.constantize
        @controller = klass.new
        num_required_parts = route.required_parts.length
        name = route.name
        nonexistent_id = -1
        if name.present?
          route_path = Rails.application.routes.url_helpers.send("#{name}_path", num_required_parts.times.map { nonexistent_id })
        else
          route_path = "/#{route.defaults[:controller]}/#{nonexistent_id}"
        end
        request_method = route.constraints[:request_method].to_s[8..-3].downcase
        begin
        r = send(request_method.to_sym, route_path)
        flunk("No exception raised with an invalid ID for #{route.inspect}")
        rescue Exception => ex
          assert_equal ActiveRecord::RecordNotFound, ex.class
        end
      end
    end
end

This came out of a discussion about testing controller actions that just do a find. I was curious if I could write a single global test that would ensure all controllers which take an ID would throw a RecordNotFound if an invalid ID was passed in. This hackish thing seems to do that. I don't know if I would actually use it, yet, but it was a fun exercise in route mapping.