1 files changed, 12 insertions, 0 deletions
diff --git a/actionpack/test/dispatch/session/mem_cache_store_test.rb b/actionpack/test/dispatch/session/mem_cache_store_test.rb
index 08f8069888..d388992b98 100644
--- a/actionpack/test/dispatch/session/mem_cache_store_test.rb
+++ b/actionpack/test/dispatch/session/mem_cache_store_test.rb
@@ -117,6 +117,18 @@ class MemCacheStoreTest < ActionController::IntegrationTest
       end
     end
 
+    def test_doesnt_write_session_cookie_if_session_id_is_already_exists
+      with_test_route_set do
+        get '/set_session_value'
+        assert_response :success
+        assert cookies['_session_id']
+
+        get '/get_session_value'
+        assert_response :success
+        assert_equal nil, headers['Set-Cookie'], "should not resend the cookie again if session_id cookie is already exists"
+      end
+    end
+
     def test_prevents_session_fixation
       with_test_route_set do
         get '/get_session_value'