tests/nlnetworkmanager/networkmanager-gtest-config.h

#define NM_DEVICE_DRIVER_6LOWPAN_DATAPOLL_TEST_FUNCTIONS \
    friend DataPollTimerParams* datapoll_test_get_timerparams(DataPollTuner& tuner); \
    friend int datapoll_test_get_current_algo(DataPollTuner& tuner);

#define NM_DEVICE_DRIVER_6LOWPAN_SILABS_TEST_FUNCTIONS \
    DataPollTuner *device_driver_silabs_test_get_polltuner(void); \
    Device::SixLoWPAN::Ember *device_driver_silabs_test_get_emberDevice(void);