1 files changed, 5 insertions, 1 deletions
diff --git a/activesupport/test/core_ext/hash_ext_test.rb b/activesupport/test/core_ext/hash_ext_test.rb
index a11cef6fc4..3fc3b86254 100644
--- a/activesupport/test/core_ext/hash_ext_test.rb
+++ b/activesupport/test/core_ext/hash_ext_test.rb
@@ -174,6 +174,10 @@ class HashExtTest < Test::Unit::TestCase
   def test_reverse_merge
     assert_equal({ :a => 1, :b => 2, :c => 10 }, { :a => 1, :b => 2 }.reverse_merge({:a => "x", :b => "y", :c => 10}) )
   end
+
+  def test_diff
+    assert_equal({ :a => 2 }, { :a => 2, :b => 5 }.diff({ :a => 1, :b => 5 }))
+  end
 end
 
 class HashToXmlTest < Test::Unit::TestCase
@@ -234,4 +238,4 @@ class HashToXmlTest < Test::Unit::TestCase
     xml = { :name => "David", :addresses => [{ :streets => [ { :name => "Paulina" }, { :name => "Paulina" } ] } ] }.to_xml(@xml_options)
     assert xml.include?(%(<addresses><address><streets><street><name>))
   end
-end
-\ No newline at end of file
+end