diff --git a/activesupport/test/gzip_test.rb b/activesupport/test/gzip_test.rb
index 6adfab0359..f564e63f29 100644
--- a/activesupport/test/gzip_test.rb
+++ b/activesupport/test/gzip_test.rb
@@ -1,4 +1,5 @@
 require 'abstract_unit'
+require 'active_support/core_ext/object/blank'
 
 class GzipTest < Test::Unit::TestCase
   def test_compress_should_decompress_to_the_same_value
@@ -14,4 +15,4 @@ class GzipTest < Test::Unit::TestCase
 
     assert !compressed.blank?, "a compressed blank string should not be blank"
   end
-end
\ No newline at end of file
+end