diff --git a/actionpack/test/controller/http_digest_authentication_test.rb b/actionpack/test/controller/http_digest_authentication_test.rb
index a91e3cafa5384da1b0543b6334414a16e7f2db16..828ea5b0fba5fb86b70ca11749dffd625672bd35 100644
--- a/actionpack/test/controller/http_digest_authentication_test.rb
+++ b/actionpack/test/controller/http_digest_authentication_test.rb
@@ -274,6 +274,6 @@ def encode_credentials(options)
   end
 
   def decode_credentials(header)
-    ActionController::HttpAuthentication::Digest.decode_credentials(@response.headers['WWW-Authenticate'])
+    ActionController::HttpAuthentication::Digest.decode_credentials(header)
   end
 end