diff --git a/lib/prototype-rails.rb b/lib/prototype-rails.rb
index 8f176f5..8739574 100644
--- a/lib/prototype-rails.rb
+++ b/lib/prototype-rails.rb
@@ -10,6 +10,12 @@ class Engine < Rails::Engine
 
       ActiveSupport.on_load(:action_view) do
         require 'prototype-rails/on_load_action_view'
+        if Rails.env.test?
+          ActionView::TestCase.class_eval do
+            include ActionView::Helpers::PrototypeHelper
+            include ActionView::Helpers::ScriptaculousHelper
+          end
+        end
       end
     end
   end
diff --git a/lib/prototype-rails/on_load_action_view.rb b/lib/prototype-rails/on_load_action_view.rb
index 2332d68..1d5c781 100644
--- a/lib/prototype-rails/on_load_action_view.rb
+++ b/lib/prototype-rails/on_load_action_view.rb
@@ -14,9 +14,4 @@
   include ActionView::Helpers::ScriptaculousHelper
 end
 
-ActionView::TestCase.class_eval do
-  include ActionView::Helpers::PrototypeHelper
-  include ActionView::Helpers::ScriptaculousHelper
-end
-
 ActionView::Template.register_template_handler :rjs, ActionView::Template::Handlers::RJS.new
diff --git a/test/lib/abstract_unit.rb b/test/lib/abstract_unit.rb
index 41b92e0..f5feb8d 100644
--- a/test/lib/abstract_unit.rb
+++ b/test/lib/abstract_unit.rb
@@ -8,6 +8,12 @@
 require 'action_view'
 require 'action_view/testing/resolvers'
 
+module Rails
+  def self.env
+    ActiveSupport::StringInquirer.new("test")
+  end
+end
+
 require 'prototype-rails/on_load_action_controller'
 require 'prototype-rails/on_load_action_view'