Problem with spring and rails engine projects

repro

#!/bin/bash -ex

gem list spring
gem list rails

rm -rf quux

rails plugin new quux --mountable

cd quux

echo 'Spring.application_root = "./test/dummy"' > config/spring.rb

cat config/spring.rb

spring status

result.txt

$ ./repro
+ gem list spring

*** LOCAL GEMS ***

spring (1.0.0)
spring-commands-rspec (1.0.1)
+ gem list rails

*** LOCAL GEMS ***

rails (3.2.16, 3.2.15)
+ rm -rf quux
+ rails plugin new quux --mountable
      create  
      create  README.rdoc
      create  Rakefile
      create  quux.gemspec
      create  MIT-LICENSE
      create  .gitignore
      create  Gemfile
      create  app
      create  app/controllers/quux/application_controller.rb
      create  app/helpers/quux/application_helper.rb
      create  app/mailers
      create  app/models
      create  app/views/layouts/quux/application.html.erb
      create  app/assets/images/quux
      create  app/assets/images/quux/.gitkeep
      create  config/routes.rb
      create  lib/quux.rb
      create  lib/tasks/quux_tasks.rake
      create  lib/quux/version.rb
      create  lib/quux/engine.rb
      create  app/assets/stylesheets/quux/application.css
      create  app/assets/javascripts/quux/application.js
      create  script
      create  script/rails
      create  test/test_helper.rb
      create  test/quux_test.rb
      append  Rakefile
      create  test/integration/navigation_test.rb
  vendor_app  test/dummy
         run  bundle install
Fetching gem metadata from https://rubygems.org/...........
Fetching gem metadata from https://rubygems.org/..
Resolving dependencies...
Using rake (10.1.0) 
Using i18n (0.6.9) 
Using multi_json (1.8.2) 
Using activesupport (3.2.16) 
Using builder (3.0.4) 
Using activemodel (3.2.16) 
Using erubis (2.7.0) 
Using journey (1.0.4) 
Using rack (1.4.5) 
Using rack-cache (1.2) 
Using rack-test (0.6.2) 
Using hike (1.2.3) 
Using tilt (1.4.1) 
Using sprockets (2.2.2) 
Using actionpack (3.2.16) 
Using mime-types (1.25.1) 
Using polyglot (0.3.3) 
Using treetop (1.4.15) 
Using mail (2.5.4) 
Using actionmailer (3.2.16) 
Using arel (3.0.3) 
Using tzinfo (0.3.38) 
Using activerecord (3.2.16) 
Using activeresource (3.2.16) 
Using bundler (1.3.5) 
Using rack-ssl (1.3.3) 
Using json (1.8.1) 
Using rdoc (3.12.2) 
Using thor (0.18.1) 
Using railties (3.2.16) 
Using jquery-rails (3.0.4) 
Using rails (3.2.16) 
Using quux (0.0.1) from source at /private/tmp/spring-engine/quux 
quux at /private/tmp/spring-engine/quux did not have a valid gemspec.
This prevents bundler from installing bins or native extensions, but that may not affect its functionality.
The validation message from Rubygems was:
  "FIXME" or "TODO" is not an author

Using sqlite3 (1.3.8) 
Your bundle is complete!
Use `bundle show [gemname]` to see where a bundled gem is installed.
+ cd quux
+ echo 'Spring.application_root = "./test/dummy"'
+ cat config/spring.rb
Spring.application_root = "./test/dummy"
+ spring status
Spring was unable to find your config/application.rb file. Your project root was detected at /private/tmp/spring-engine/quux, so spring looked for /private/tmp/spring-engine/quux/config/application.rb but it doesn't exist. You can configure the root of your application by setting Spring.application_root in config/spring.rb.