@Override
    public RxBleDevice getBleDevice(@NonNull final String macAddress) {

        Object[] rxBleDevices = discoveredDevicesSubject
                .getValues();
        for (Object device : rxBleDevices) {
            if (((RxBleDevice) device).getMacAddress().equals(macAddress)) {
                return (RxBleDevice) device;
            }
        }
        throw new IllegalStateException("Mock is not configured for a given mac address. Use Builder#addDevice method.");
    }
Create the  {@link List} of {@link BluetoothGattDescriptor} using the configured values.
mockrxandroidble/src/main/java/com/polidea/rxandroidble2/mockrxandroidble/RxBleClientMock.java