diff --git a/lib/json.rb b/lib/json.rb
index b5a6912415..bf93c663fe 100644
--- a/lib/json.rb
+++ b/lib/json.rb
@@ -55,9 +55,5 @@
 module JSON
   require 'json/version'
 
-  begin
-    require 'json/ext'
-  rescue LoadError
-    require 'json/pure'
-  end
+  require 'json/pure'
 end
--- a/tests/test_helper.rb
+++ b/tests/test_helper.rb
@@ -1,16 +1,7 @@
 gem 'json', File.read('VERSION').chomp
 
-case ENV['JSON']
-when 'pure'
-  $:.unshift 'lib'
-  require 'json/pure'
-when 'ext'
-  $:.unshift 'ext', 'lib'
-  require 'json/ext'
-else
-  $:.unshift 'ext', 'lib'
-  require 'json'
-end
+$:.unshift 'lib'
+require 'json'
 
 require 'test/unit'
 begin