I think TDD is only done correctly if unit tests are black box. You write your tests and thereby define your interface, regardless of the implementation behind it. Once you get to the refactoring stage you (may) change your implementation to make your code better organized|more efficient|less redundant|etc. Your refactoring succeeds if you manage to change your implementation without breaking a test. If you then have code that's not being tested, you have one of two cases
- Your tests don't accurately describe your interface, because you forgot to test for an outcome that should be part of your spec.
- The untested code should be removed because it produces an outcome not included in the spec (because ideally your tests are the most thorough description of the spec)
In the case of 1. you need to add a test, but you still want to test against the module interface, not against the particular implementation. This is a corner case where you're actually finding a better interface by coincidence while refactoring. If you're writing your tests correctly it shouldn't happen (though IRL it does).
I do agree that it takes a special sort of mindset to properly separate your test-writing brain from your implementing brain, so that's a practical problem for all but the schizophrenics among us :-).
Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
Read Where should I post X? if you're not absolutely sure you're posting in the right place.
Please read these before you post! —
Posts may use any of the Perl Monks Approved HTML tags:
You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
- a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
Link using PerlMonks shortcuts! What shortcuts can I use for linking?
See Writeup Formatting Tips and other pages linked from there for more info.
| & || & |
| < || < |
| > || > |
| [ || [ |
| ] || ] ||