Fix i18n locales order test.

activesupport/lib/active_support/railtie.rb

@@ -33,6 +33,7 @@ module I18n
     railtie_name :i18n
 
     # Initialize I18n load paths to an array
+    config.i18n.engines_load_path = []
     config.i18n.load_path = []
 
     initializer :initialize_i18n do
@@ -47,7 +48,10 @@ module I18n
     # the load_path which should be appended to what's already set instead of overwritten.
     config.after_initialize do |app|
       app.config.i18n.each do |setting, value|
-        if setting == :load_path
+        case setting
+        when :engines_load_path
+          app.config.i18n.load_path.unshift(*value)
+        when :load_path
           I18n.load_path += value
         else
           I18n.send("#{setting}=", value)

railties/lib/rails/engine.rb

@@ -57,12 +57,12 @@ module Rails
     # Set the paths from which Rails will automatically load source files,
     # and the load_once paths.
     initializer :set_autoload_paths do |app|
-      ActiveSupport::Dependencies.load_paths.concat(config.load_paths)
+      ActiveSupport::Dependencies.load_paths.unshift(*config.load_paths)
 
       if reloadable?(app)
-        ActiveSupport::Dependencies.load_once_paths.concat(config.load_once_paths)
+        ActiveSupport::Dependencies.load_once_paths.unshift(*config.load_once_paths)
       else
-        ActiveSupport::Dependencies.load_once_paths.concat(config.load_paths)
+        ActiveSupport::Dependencies.load_once_paths.unshift(*config.load_paths)
       end
 
       # Freeze so future modifications will fail rather than do nothing mysteriously
@@ -86,18 +86,20 @@ module Rails
       end
     end
 
+    # I18n load paths are a special case since the ones added
+    # later have higher priority.
     initializer :add_locales do
-      config.i18n.load_path.unshift(*paths.config.locales.to_a)
+      config.i18n.engines_load_path.concat(paths.config.locales.to_a)
     end
 
     initializer :add_view_paths do
       views = paths.app.views.to_a
-      ActionController::Base.view_paths.concat(views) if defined?(ActionController)
-      ActionMailer::Base.view_paths.concat(views)     if defined?(ActionMailer)
+      ActionController::Base.view_paths.unshift(*views) if defined?(ActionController)
+      ActionMailer::Base.view_paths.unshift(*views)     if defined?(ActionMailer)
     end
 
     initializer :add_metals do
-      Rails::Rack::Metal.paths.concat(paths.app.metals.to_a)
+      Rails::Rack::Metal.paths.unshift(*paths.app.metals.to_a)
     end
 
     initializer :load_application_initializers do