Howdy Jamie and thanks so much for your question.
I just spoke with a Cast Member and at this time, there is no confirmed information regarding when
Disney's Saratoga Springs Resort and Spa will be part of the MagicBand testing.
For future reference, should Saratoga Springs become part of the testing prior to your arrival, you will receive notification from a Disney Cast Member that you have been selected to take part in the testing. Following your notification, your Magic Bands will be shipped to you.
Be sure to check the Walt Disney World website often for updates.
MyMagic+ is such an amazing initiative and I know it's going to enhance all of our future Walt Disney World Resort vacations!
Thanks so much for your question and please let me know if you need any further information. Have a magical day!