It depends on when the test will be. If it is fairly early then reload in the AM is not a good idea. It takes some time for the nutrients to be stored in the muscle and pull water with them. If you are not done digesting, not only will you not get the "loading" benefit, you will also have low energy because of the digestive process. Furthermore is you load too early in the day THEN lift, you run the chance of having an energy crash from low blood sugar.
Ideally the best is to load the evening/night before, and eat a few moderate carbs but high sodium meals prior to lifting and HYDRATE.