diff --git a/actionpack/test/dispatch/mapper_test.rb b/actionpack/test/dispatch/mapper_test.rb
index <HASH>..<HASH> 100644
--- a/actionpack/test/dispatch/mapper_test.rb
+++ b/actionpack/test/dispatch/mapper_test.rb
@@ -38,7 +38,7 @@ module ActionDispatch
 
       def test_mapping_requirements
         options = { :controller => 'foo', :action => 'bar', :via => :get }
-        m = Mapper::Mapping.new({}, '/store/:name(*rest)', options)
+        m = Mapper::Mapping.build({}, '/store/:name(*rest)', options)
         _, _, requirements, _ = m.to_route
         assert_equal(/.+?/, requirements[:rest])
       end
use the factory method to construct the mapping