Wonder if the 'testing' of click counts has produce any noticeable track deviations yet
On the FBW Airbus, rotating any of the four knobs in question will cause the numerical display above it to unblank and indicate the value selected*. The knobs can be rotated round and round to change their respective values on these FCU displays. However, unless the knobs are actually pulled as well as turned, the aircraft will ignore them**, so the number of clicks per turn or the increment per click can be ascertained without the aircraft deviating at all
*Apart from the altitude display which is always active and does not blank.
** Apart from the altitude knob which will change the altitude pre-selected, but the aircraft will not react until the knob is pushed or pulled.