Why would it even be okay at all for a piece of code that determines the seed for a pseudo RNG via observation of hardware events (a Geiger counter measurement,

Why would it even be okay at all for a piece of code that determines the seed for a pseudo RNG via observation of hardware events (a Geiger counter measurement, according to the article) to even access the date and time on a given system? It should have no use for that information, and with a piece of code of that criticality, one would expect auditors to scrutinize any and all syscalls that it performs. This way it should have been fairly obvious that it's requesting the time from the OS, which it shouldn't do in the first place. Mocking date/time info is unnecessary if your code under test is entirely unable to get time information from the system in the first place.