Currently the Bluetooth Low Energy GATT server events aren't being tested by API tests. To add API tests for these that are really effective, we need to do the following,

a.) Integrate the BluetoothLowEnergyApiTestChromeOs tests with BluetoothTestBlueZ. This will allow us to have a lot of control over our environment.
b.) Write tests that simulate real events being sent from DBus all the way to the test app.

Without this, our tests will miss considerable amount of coverage. All the code that handles actual events being sent from DBus and back isn't going to get exercised.

Currently all extension functions are being tested this way (with actual underlying code being called to test the full stack), we need to add more support code to be able to do the same for events.