I wonder if there is a way to simulate NO GPS signal without going in the basement. As if you were inside a tunnel or under the earth surface. I am not talking about location mocking. I wonder if we can leave the GPS turned on but prevent application from getting a GPS fix.
You want a Faraday cage. There are do-it-yourself instructions for making one out of aluminum foil. You can also approximate one by trying prebuilt metal boxes like microwave ovens, metal filing cabinets, or refrigerators. Just put your device inside to see whether it blocks the GPS signal.