diff --git a/test/json/json_parser_test.rb b/test/json/json_parser_test.rb
index f36e9c84e1..5f454eb121 100644
--- a/test/json/json_parser_test.rb
+++ b/test/json/json_parser_test.rb
@@ -4,6 +4,7 @@ require 'test_helper'
 require 'stringio'
 require 'tempfile'
 require 'ostruct'
+require 'bigdecimal'
 
 class JSONParserTest < Test::Unit::TestCase
   include JSON