I've now written the first #gherkin #bdd features for testing the @bifravst firmware on real hardware: https://github.com/bifravst/firmware/blob/d3903b83c5aa3f75acedcc79d7171c9786241c9f/features/RunFirmware.feature
I think that's a good way to express what should happen when the firmware is running.
Here is another example of a feature: https://github.com/bifravst/firmware/blob/d3903b83c5aa3f75acedcc79d7171c9786241c9f/features/CheckModemFirmware.feature