Gem plugins, autoloading, and dev mode reloading

Putting this code in initializers/gem_hook.rb

module GemHook
  def self.included(base) #:nodoc:
    base.instance_eval do
      unless defined? gem_without_load_once_paths
        alias_method_chain :gem, :load_once_paths
      end
    end
  end

  def gem_with_load_once_paths(gem_name, *version_requirements)
    old_load_paths = $LOAD_PATH.dup
    result = gem_without_load_once_paths(gem_name, *version_requirements)
    new_load_paths = $LOAD_PATH.dup
    added_paths = new_load_paths - old_load_paths
    ActiveSupport::Dependencies.load_paths |= added_paths
    ActiveSupport::Dependencies.load_once_paths |= added_paths
    result
  end
end

Kernel.instance_eval { include GemHook }

makes the behavior consistent. It would be straightforward to incorporate this into dependencies.rb, but how would this function be tested?