http://www.perlmonks.org?node_id=502803


in reply to Re^2: (OT) Black- vs. white-box testing
in thread (OT) Black- vs. white-box testing

Then I agree with OP that such a practice (white-box tests) are, in general, a CodeSmell. If one considered the data structure C to be important enough to warrant a test, then he should refactor, or enrich the interface (spec) so as to include it too.