Set locale to something other than the default

Demonstrate regression introduced by https://github.com/svenfuchs/i18n/commit/b5703d7431

bundle exec /home/rubys/git/rails/railties/bin/rails new demo --skip-bundle
      create  
      create  README.rdoc
      create  Rakefile
      create  config.ru
      create  .gitignore
      create  Gemfile
      create  app
      create  app/assets/javascripts/application.js
      create  app/assets/stylesheets/application.css
      create  app/controllers/application_controller.rb
      create  app/helpers/application_helper.rb
      create  app/views/layouts/application.html.erb
      create  app/assets/images/.keep
      create  app/mailers/.keep
      create  app/models/.keep
      create  app/controllers/concerns/.keep
      create  app/models/concerns/.keep
      create  bin
      create  bin/bundle
      create  bin/rails
      create  bin/rake
      create  bin/setup
      create  config
      create  config/routes.rb
      create  config/application.rb
      create  config/environment.rb
      create  config/secrets.yml
      create  config/environments
      create  config/environments/development.rb
      create  config/environments/production.rb
      create  config/environments/test.rb
      create  config/initializers
      create  config/initializers/assets.rb
      create  config/initializers/backtrace_silencers.rb
      create  config/initializers/cookies_serializer.rb
      create  config/initializers/filter_parameter_logging.rb
      create  config/initializers/inflections.rb
      create  config/initializers/mime_types.rb
      create  config/initializers/session_store.rb
      create  config/initializers/wrap_parameters.rb
      create  config/locales
      create  config/locales/en.yml
      create  config/boot.rb
      create  config/database.yml
      create  db
      create  db/seeds.rb
      create  lib
      create  lib/tasks
      create  lib/tasks/.keep
      create  lib/assets
      create  lib/assets/.keep
      create  log
      create  log/.keep
      create  public
      create  public/404.html
      create  public/422.html
      create  public/500.html
      create  public/favicon.ico
      create  public/robots.txt
      create  test/fixtures
      create  test/fixtures/.keep
      create  test/controllers
      create  test/controllers/.keep
      create  test/mailers
      create  test/mailers/.keep
      create  test/models
      create  test/models/.keep
      create  test/helpers
      create  test/helpers/.keep
      create  test/integration
      create  test/integration/.keep
      create  test/test_helper.rb
      create  tmp/cache
      create  tmp/cache/assets
      create  vendor/assets/javascripts
      create  vendor/assets/javascripts/.keep
      create  vendor/assets/stylesheets
      create  vendor/assets/stylesheets/.keep
bundle install --local
Resolving dependencies...
Using rake 10.3.2
Using i18n 0.6.11 from source at /home/rubys/git/i18n
Using json 1.8.1
Using minitest 5.4.0
Using thread_safe 0.3.4
Using tzinfo 1.2.1
Using activesupport 4.2.0.alpha from source at /home/rubys/git/rails
Using builder 3.2.2
Using erubis 2.7.0
Using actionview 4.2.0.alpha from source at /home/rubys/git/rails
Using rack 1.6.0.alpha from source at /home/rubys/git/rack
Using rack-test 0.6.2
Using actionpack 4.2.0.alpha from source at /home/rubys/git/rails
Using mime-types 2.3
Using mail 2.6.1
Using actionmailer 4.2.0.alpha from source at /home/rubys/git/rails
Using activemodel 4.2.0.alpha from source at /home/rubys/git/rails
Using arel 6.0.0.20140505020427 from source at /home/rubys/git/arel
Using activerecord 4.2.0.alpha from source at /home/rubys/git/rails
Using bundler 1.6.4
Using coffee-script-source 1.7.1
Using execjs 2.2.1
Using coffee-script 2.3.0
Using thor 0.19.1
Using railties 4.2.0.alpha from source at /home/rubys/git/rails
Using coffee-rails 4.0.1 from source at /home/rubys/git/coffee-rails
Using hike 1.2.3
Using multi_json 1.10.1
Using jbuilder 2.1.3
Using jquery-rails 3.1.1
Using tilt 1.4.1
Using sprockets 2.12.1
Using sprockets-rails 2.1.2 from source at /home/rubys/git/sprockets-rails
Using rails 4.2.0.alpha from source at /home/rubys/git/rails
Using rdoc 4.1.1
Using sass 3.3.10
Using sass-rails 5.0.0.dev from source at /home/rubys/git/sass-rails
Using sdoc 0.4.0
Using spring 1.1.3
Using sqlite3 1.3.9
Using turbolinks 2.2.2
Using uglifier 2.5.3
Your bundle is complete!
Use `bundle show [gemname]` to see where a bundled gem is installed.

Define :es locale

edit config/locales/es.yml
  es:
    hello: 'Hola mundo' 

Dump available locales

rails runner "p I18n.available_locales"
[:en, :es]

Set locale to en

rails runner "p (I18n.locale = 'en')"
"en"

Set locale to es

rails runner "p (I18n.locale = 'es')"
"es"

Set default locale

edit config/initializers/i18n.rb
  I18n.default_locale = :en

Dump available locales

rails runner "p I18n.available_locales"
[:en, :es]

Set locale to en

rails runner "p (I18n.locale = 'en')"
"en"

Set locale to es

rails runner "p (I18n.locale = 'es')"
/home/rubys/git/i18n/lib/i18n.rb:283:in `enforce_available_locales!': "es" is not a valid locale (I18n::InvalidLocale)
	from /home/rubys/git/i18n/lib/i18n/config.rb:13:in `locale='
	from /home/rubys/git/i18n/lib/i18n.rb:35:in `locale='
	from /home/rubys/git/rails/railties/lib/rails/commands/runner.rb:62:in `<top (required)>'
	from /home/rubys/git/rails/railties/lib/rails/commands/runner.rb:62:in `eval'
	from /home/rubys/git/rails/railties/lib/rails/commands/runner.rb:62:in `<top (required)>'
	from /home/rubys/git/rails/railties/lib/rails/commands/commands_tasks.rb:123:in `require'
	from /home/rubys/git/rails/railties/lib/rails/commands/commands_tasks.rb:123:in `require_command!'
	from /home/rubys/git/rails/railties/lib/rails/commands/commands_tasks.rb:90:in `runner'
	from /home/rubys/git/rails/railties/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
	from /home/rubys/git/rails/railties/lib/rails/commands.rb:17:in `<top (required)>'
	from bin/rails:4:in `require'
	from bin/rails:4:in `<main>'
Expected at least 1 element matching ".stdout", found 0.
<0> expected to be
>=
<1>.

Traceback:
  locale.rb:60:in `block (2 levels) in <class:Locale>'
  /home/rubys/git/gorp/lib/gorp/test.rb:158:in `call'
  /home/rubys/git/gorp/lib/gorp/test.rb:158:in `block (2 levels) in <class:TestCase>'
  locale.rb:59:in `block in <class:Locale>'

Environment

Sun, 20 Jul 2014 19:56:30 GMT
git log -1
commit 08754f12e65a9ec79633a605e986d0f1ffa4b251
Merge: 0533893 fd6aaaa
Author: Rafael Mendonça França <rafaelmfranca@gmail.com>
Date:   Sat Jul 19 18:17:13 2014 -0300

    Merge branch 'rm-remove-mocha'
    
    Conflicts:
    	actionpack/test/abstract_unit.rb
rake about
About your application's environment
Ruby version              2.1.0-p0 (x86_64-linux)
RubyGems version          2.2.2
Rack version              1.5
Rails version             4.2.0.alpha
JavaScript Runtime        Node.js (V8)
Active Record version     4.2.0.alpha
Action Pack version       4.2.0.alpha
Action View version       4.2.0.alpha
Action Mailer version     4.2.0.alpha
Active Support version    4.2.0.alpha
Active Model version      4.2.0.alpha
Middleware                Rack::Sendfile,
                          ActionDispatch::Static,
                          Rack::Lock,
                          #<ActiveSupport::Cache::Strategy::LocalCache::Middleware:0x00000004781050>,
                          Rack::Runtime,
                          Rack::MethodOverride,
                          ActionDispatch::RequestId,
                          Rails::Rack::Logger,
                          ActionDispatch::ShowExceptions,
                          ActionDispatch::DebugExceptions,
                          ActionDispatch::RemoteIp,
                          ActionDispatch::Reloader,
                          ActionDispatch::Callbacks,
                          ActiveRecord::Migration::CheckPending,
                          ActiveRecord::ConnectionAdapters::ConnectionManagement,
                          ActiveRecord::QueryCache,
                          ActionDispatch::Cookies,
                          ActionDispatch::Session::CookieStore,
                          ActionDispatch::Flash,
                          ActionDispatch::ParamsParser,
                          Rack::Head,
                          Rack::ConditionalGet,
                          Rack::ETag
Application root          /var/www/rtest/work-210/demo
Environment               development
Database adapter          sqlite3
Database schema version   0
bundle show
Gems included by the bundle:
  * actionmailer (4.2.0.alpha)
  * actionpack (4.2.0.alpha)
  * actionview (4.2.0.alpha)
  * activemodel (4.2.0.alpha)
  * activerecord (4.2.0.alpha)
  * activesupport (4.2.0.alpha)
  * arel (6.0.0.20140505020427)
  * builder (3.2.2)
  * bundler (1.6.4)
  * coffee-rails (4.0.1)
  * coffee-script (2.3.0)
  * coffee-script-source (1.7.1)
  * erubis (2.7.0)
  * execjs (2.2.1)
  * hike (1.2.3)
  * i18n (0.6.11)
  * jbuilder (2.1.3)
  * jquery-rails (3.1.1)
  * json (1.8.1)
  * mail (2.6.1)
  * mime-types (2.3)
  * minitest (5.4.0)
  * multi_json (1.10.1)
  * rack (1.6.0.alpha)
  * rack-test (0.6.2)
  * rails (4.2.0.alpha)
  * railties (4.2.0.alpha)
  * rake (10.3.2)
  * rdoc (4.1.1)
  * sass (3.3.10)
  * sass-rails (5.0.0.dev)
  * sdoc (0.4.0)
  * spring (1.1.3)
  * sprockets (2.12.1)
  * sprockets-rails (2.1.2)
  * sqlite3 (1.3.9)
  * thor (0.19.1)
  * thread_safe (0.3.4)
  * tilt (1.4.1)
  * turbolinks (2.2.2)
  * tzinfo (1.2.1)
  * uglifier (2.5.3)
gem -v
2.2.2
/home/rubys/.rvm/rubies/ruby-2.1.0/bin/ruby -v
ruby 2.1.0p0 (2013-12-25 revision 44422) [x86_64-linux]
rvm -v
1.25.28 (stable)
nodejs -v
v0.10.25
echo $PATH
/home/rubys/.rvm/gems/ruby-2.1.0/bin
/home/rubys/.rvm/gems/ruby-2.1.0@global/bin
/home/rubys/.rvm/rubies/ruby-2.1.0/bin
/home/rubys/.rvm/bin
/home/rubys/bin
/usr/local/sbin
/usr/local/bin
/usr/sbin
/usr/bin
/sbin
/bin
/usr/games
/usr/local/games
lsb_release -irc
Distributor ID:	Ubuntu
Release:	14.04
Codename:	trusty
uname -srm
Linux 3.13.0-32-generic x86_64