diff --git a/test/unit/checkout_command_xml_generator_test.rb b/test/unit/checkout_command_xml_generator_test.rb
index 3aec448..3f4eb9e 100644
--- a/test/unit/checkout_command_xml_generator_test.rb
+++ b/test/unit/checkout_command_xml_generator_test.rb
@@ -190,7 +190,7 @@ def assert_google_checkout_diagnose_returns_no_warnings(xml_str)
       
         # Check that there is no <warnings> tag in the XML.
         xml_document = REXML::Document.new(res.body)
-        assert 0, xml_document.root.elements.to_a('//warnings').size
+        assert_equal 0, xml_document.root.elements.to_a('//warnings').size
       end      
     end