I agree with first point “Nil Check on a Dependency” and disagree with 2nd point

“Nil Check on a Dependency in the Constructor”, at least in the way it is described in article’s example.

The _parameter_ check in the constructor is the standard practice of testing on perimeter/blundaries. You test your parameters on the public methods (that constructor obviously is), and assume valid state in private methods. And even there I can accept practice of debug build assertions (DCHECK/TCHECK in Google c++ terminology ).