[bdangubic]

laziness? unprofessionalism? both? or something else?

[spc476]

You forgot difficult. How do you test a system call failure? How do you test a system call failure when the first N calls need to pass? Be careful how you answer, some answers technically fall into the "undefined behavior" category (if you are using C or C++).

[zahlman]

... Is that not what mocking is for?

[rvz]

all of the above.