What are some reasons why a sole developer should use TDD? [closed]

Question

I'm a contract programmer with lots of experience. I'm used to being hired by a client to go in and do a software project of one form or another on my own, usually from nothing. That means a clean slate, almost every time. I can bring in libraries I've developed to get a quick start, but they're always optional. (and depend on getting the right IP clauses in the contract) Many times I can specify or even design the hardware platform... so we're talking serious freedom here.

I can see uses for constructing automated tests for certain code: Libraries with more than trivial functionality, core functionality with a high number of references, etc. Basically, as the value of a piece of code goes up through heavy use, I can see it would be more and more valuable to automatically test that code so that I know I don't break it.

However, in my situation, I find it hard to rationalize anything more than that. I'll adopt things as they prove useful, but I'm not about to blindly follow anything.

I find many of the things I do in 'maintenance' are actually small design changes. In this case, the tests would not have saved me anything and now they'd have to change too. A highly iterative, stub-first design approach works very well for me. I can't see actually saving myself that much time with more extensive tests.

Hobby projects are even harder to justify... they're usually anything from weekenders up to a say month long. Edge-case bugs rarely matter, it's all about playing with something.

Reading questions such as this one, The most voted on response seems to say that in that poster's experience/opinion TDD actually wastes time if you've got less than 5 people (even assuming a certain level of competence/experience with TDD). However, that appears to be covering initial development time, not maintenance. It's not clear how TDD stacks up over the entire life cycle of a project.

I think TDD could be a good step in the worthwhile goal of improving the quality of the products of our industry as a whole. Idealism on it's own is no longer all that effective at motivating me, though.

I do think TDD would be a good approach in large teams, or any size team containing at least one unreliable programmer. That's not my question.

Why would a sole developer with a good track record adopt TDD?

I'd love to hear of any kind of metrics done (formally or not) on TDD... focusing on solo developers or very small teams.

Failing that, anecdotes of your personal experiences would be nice, too. :)

Please avoid stating opinion without experience to back it. Let's not make this an ideology war. Also the skip greater employment options argument. This is simply an efficiency question.

Answer 1

I find it even more useful when flying solo. With nobody around to bounce ideas off of and nobody around to perform peer reviews, you will need some assurance that you're code is solid. TDD/BDD will provide that assurance for you. TDD is a bit contraversial, though. Others may completely disagree with what I'm saying.

EDIT: Might I add that if done right, you can actually generate specifications for your software at the same time you write tests. This is a great side effect of BDD. You can make yourself look like super developer if you're cranking out solid code along with specs, all on your own.

Answer 2

I'm not about to blindly follow anything.

That's the right attitude. I use TDD all the time, but I don't adhere to it as strictly as some.

The best argument (in my mind) in favor of TDD is that you get a set of tests you can run when you finally get to the refactoring and maintenance phases of your project. If this is your only reason for using TDD, then you can write the tests any time you want, instead of blindly following the methodology.

The other reason I use TDD is that writing tests gets me thinking about my API up front. I'm forced to think about how I'm going to use a class before I write it. Getting my head into the project at this high level works for me. There are other ways to do this, and if you've found other methods (there are plenty) to do the same thing, then I'd say keep doing what works for you.