diff --git a/actionpack/lib/action_controller/test_case.rb b/actionpack/lib/action_controller/test_case.rb
index bb73f359c941e6326ace245e564ab3a1b7573301..24c07f02e0db6cb499f98c970b8072ea430f7e64 100644
--- a/actionpack/lib/action_controller/test_case.rb
+++ b/actionpack/lib/action_controller/test_case.rb
@@ -510,10 +510,10 @@ def process(action, *args)
 
         @request.env.delete 'HTTP_COOKIE'
 
-        if cookies = @request.env['action_dispatch.cookies']
+        if @request.have_cookie_jar?
           unless @response.committed?
-            cookies.write(@response)
-            self.cookies.update(cookies.instance_variable_get(:@cookies))
+            @request.cookie_jar.write(@response)
+            self.cookies.update(@request.cookie_jar.instance_variable_get(:@cookies))
           end
         end
         @response.prepare!