How do you maintain discipline when doing TDD? [closed]

Question

When I get excited about a new feature I'm just about to implement or about a bug that I've just "understood", there is the urge to just jump into the code and get hacking. It takes some effort to stop myself from doing that and to write the corresponding test first. Later the test often turns out to be trivial 4-liner, but before writing it still there's the thought in back of a head, "maybe I can skip this one, this one time?" Ideally I'd like to get an urge to write test, and only then, perhaps, the code :)

What method (or way of thinking or mind trick or self-reward policy or whatever) do you use to help maintain the discipline? Or do you just practice it until it feels natural?

Answer 1

I like the instant feedback from the test, that's reward enough for me. If I can reproduce a bug in a test that's a good feeling, I know I'm headed in the right direction as opposed to guessing and possibly wasting my time.

I like working Test-First because I feel like it keeps me more in tune with what the code is actually doing as opposed to guessing based on a possibly inaccurate mental model. Being able to confirm my assumptions iteratively is a big payoff for me.

Answer 2

I find that writing tests helps me to sketch out my approach to the problem at hand. Often, if you can't write a good test, it means you haven't necessarily thought enough about what it is that you're supposed to be doing. The satisfaction of being confident that I know how to tackle the problem once the tests are written is rather useful.

Answer 3

I'll let you know when I find a method that works. :-)

But seriously, I think your "practice until it feels natural" comment pretty much hits the nail on the head. A 4 line test may appear trivial, but as long as what you are testing represents a real failure point then it is worth doing.

One thing I have found to be helpful is to include code coverage validation as part of the build process. If I fail to write tests, the build will complain at me. If I continue failing to write tests, the continuous integration build will "error out" and everyone nearby will hear the sound I have wired to the "broken build" notification. After a few weeks of "Good grief... You broke it again?", and similar comments, I soon started writing more tests to avoid embarrassment.

One other thing (which only occurred to me after I had submitted the answer the first time) is that once I really got into the habit of writing tests first, I got great positive reinforcement from the fact that I could deliver bug-fixes and additional features with much greater confidence than I could in my pre-automated-test days.

Answer 4

Easiest way I've found is to just use TDD a lot. At some point, writing code without unit tests becomes a very, very nervous activity.

Also, try to focus on interaction or behavioral testing rather than state-based testing.