Pro Tip: Bluetooth Testing On The Cheap
Developing with bluetooth requires a lot of connectivity testing. You should invest in a high quality faraday bag in which you can place your bluetooth device in order to test various disconnect/reconnect states.
You don't always have your costly faraday bags with you, and you might be want to run some tests. Say you're working on an IoT device that needs to talk to an app on your phone. You might want to test how the app handles the device going away or suddenly coming into range.
A microwave will hide your bluetooth device well (no cooking needed!) Throw the device into the microwave, shut the door, and walk about 10 feet away and your bluetooth connection will be severed.
If you don't have a microwave sitting around, but you do have tinfoil - simply wrap the device in the tinfoil so that it is watertight. If water wouldn't escape the wrapping, your bluetooth signal probably won't either.
So if you find yourself short of an expensive faraday bag, a microwave or some tinfoil goes a long way.