Stories about Software


TDD Chess Game Part 3: Stumbling and Refactoring

My apologies. I meant to be a little more regular in this series, but I stumbled a bit out of the gate, as I got into the home stretch of my next Pluralsight course. Now that the course is delivered (not released yet – in the review/edit phase), I have some more time, so I’m planning to pick this back up and go with it a little more regularly.

One interesting thing that arises out of these “fits and starts” kind of passes at it is that it mimics an actual, common development scenario: spotty maintenance coding. What I mean is, so many TDD series that you’ll watch or coding dojo/exercises in which you’ll participate have a premise that you have some fixed length of time during which to pay complete attention. But in this series, I’m sort of poking at it for 10 minutes here and 20 minutes there, very seriously mimicking an environment where you’re plugging a lot of holes, thrashing a bit and saying, “where was I and what was I dong here?”

That’s evident in this clip, probably a little too much for me really to call it polished. And as such, I don’t accomplish a ton, but here’s what I did accomplish (not necessarily in order):

  • Tied up a loose end by getting rid of the last of the primitive obsession passing of x and y coordinate ints.
  • Implemented sanity precondition checks for the input Board’s AddPiece() method, in terms of where pieces could be placed.
  • Pushed functionality for validating coordinates into the coordinate itself.
  • Eliminated duplication in the validation with a refactoring.

And, here are some lessons to take away from this, both instructional from me and by watching me make mistakes:

  • After a conceptual refactoring, such as replacing multiple primitives with a type, take a look around to make sure you cleaned up all instances of the former.
  • When you’re not really sure what to do next (i.e. “coder’s block” or “paralysis by analysis”), implement some sanity checks for preconditions/invariants. This might jolt you into some next steps as you do it.
  • Make ABSOLUTELY SURE that a test goes red when you think it should go red. Not understanding why a unit test is passing is just as bad as not understanding why it’s failing. In both cases, it means you don’t understand what your code is doing. Stop everything and get your brain in sync with the code immediately to save yourself a lot of frustration later. (See “programming by coincidence,” which I saw coined in the book “The Pragmatic Programmer” — and then, don’t do it!)
  • You’re going to make mistakes. Often dumb ones. The beauty of TDD and its fast feedback loop is to prevent them from festering and being worse later.
  • This is more of an editorial/opinion take, but I’ve more recently gravitated toward allowing my TDD to include what might be called “integration tests” (tests that exercise the interaction between two classes). As long as the test makes sense from a behavioral standpoint and provides clarity, I think it’s fine. Some, particularly those in the BDD camp, even argue that this is preferred, and that your tests should really only go through the outer API of your module/application.
  • Eliminate duplication, however trivial and however subtle. If you see repetition of any kind, you can probably extract a method. Some productivity tools and IDEs will even help you locate possible duplication.

Finally, a few notes on the video itself (and resultant code):

  • For those of you who suggested a larger font size, look for that in part 4. I apologize, but I had actually recorded the video for this already when I was taking suggestions. In the production, I did zoom to a slightly smaller area, so we’ll see if that helps any.
  • I had one commenter express a preference for a white background instead of the VS Dark theme that I use. White work-spaces give me a headache, so I darken all IDEs and things that I work in. For one person, I don’t think I’ll pull the trigger, but if more people start responding and expressing that preference, I’ll agree to suck it up and change colors.
  • The code is now on github. I’ll commit the code each time I record the video and tag it with a comment corresponding to the part of the series in question. The initial push to master just reads “Initial publish to Github” but it corresponds to the code at the end of this clip. From here forward, I’ll sync them, though if you check the repo, it’ll probably run slightly ahead of me publishing the videos because I record the audio and do these writeups after the fact.
  • Again, the higher res you view this in the better. I’d go for 1440P if you can.

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[…] >> TDD Chess Game Part 3: Stumbling and Refactoring […]

Brad Rembielak
Brad Rembielak
10 years ago

Like you, I find the dark theme better to work in, BUT the dark theme is harder to read on screencasts most probably because a screencast is just a little fuzzier.

Here’s a post by Scott Hanselman that recommends greater font sizes and white backgrounds for screenshots and screencasts:


Erik Dietrich
9 years ago
Reply to  Brad Rembielak

Thanks for the link. He’s got some great points in there — I’ve never really given much thought to anything when taking screenshots. I’ve been thinking about it over the weekend, and think I might grit my teeth and at least try doing the next screencast in black on white.