1 files changed, 12 insertions, 1 deletions
diff --git a/railties/test/isolation/abstract_unit.rb b/railties/test/isolation/abstract_unit.rb
index 69208ce4c3..685d1b154b 100644
--- a/railties/test/isolation/abstract_unit.rb
+++ b/railties/test/isolation/abstract_unit.rb
@@ -91,6 +91,9 @@ module TestHelpers
   module Generation
     # Build an application by invoking the generator and going through the whole stack.
     def build_app(options = {})
+      @prev_rails_env = ENV['RAILS_ENV']
+      ENV['RAILS_ENV'] = 'development'
+
       FileUtils.rm_rf(app_path)
       FileUtils.cp_r(tmp_path('app_template'), app_path)
 
@@ -115,6 +118,10 @@ module TestHelpers
       add_to_config 'config.secret_token = "3b7cd727ee24e8444053437c36cc66c4"; config.session_store :cookie_store, :key => "_myapp_session"; config.active_support.deprecation = :log'
     end
 
+    def teardown_app
+      ENV['RAILS_ENV'] = @prev_rails_env if @prev_rails_env
+    end
+
     # Make a very basic app, without creating the whole directory structure.
     # This is faster and simpler than the method above.
     def make_basic_app
@@ -231,6 +238,10 @@ module TestHelpers
       end
     end
 
+    def remove_file(path)
+      FileUtils.rm_rf "#{app_path}/#{path}"
+    end
+
     def controller(name, contents)
       app_file("app/controllers/#{name}_controller.rb", contents)
     end
@@ -280,4 +291,4 @@ Module.new do
     end
     f.puts "require 'rails/all'"
   end
-end
+end unless defined?(RAILS_ISOLATED_ENGINE)