For the record, I have been a software developer since 1970, and have worked at several different startups. One in 1976 which was a great success; and another in 1987 which muddled and eventually failed. I have started several of my own companies since 1990. I have recently founded cleancoders.com, which is a very successful video training startup using TDD for the website. I also work for 8th Light which is a consulting company started by my son 6 years ago, and is dedicated to TDD.
I have been practicing TDD since 1999; and have found very few situations in which it does not help me be both better and faster at my job. I would certainly never hire anyone who did not practice it.
I don't understand how your experience at startups in 1976 and 1987, which happened 23 and 12 years respectively before you started practicing TDD, give you any information on the use of TDD in a startup environment. Consulting doesn't count, because theoretically you've sold your client on TDD's value and they're willing to pay.
Again, understand that I am not challenging your overall experience or skill. I'm not even arguing that TDD is a bad practice or that testing doesn't lead to better code. I'm saying that you are ignoring the most important factor in the success of most startups: the ability to get a product to market quickly and iterate rapidly to solve problem that is not well understood.
I started a (relatively) successful startup called AgileZen in 2009. When I started developing the first version, I obsessively wrote tests. That lasted about two weeks before I deleted the entire battery.
Now, I believe that testing helps create good software. So why would I trash the tests? Because it was a bootstrapped startup. We had no revenue coming in and I was burning through the small amount of money we had in the bank. We hadn't launched our product yet. We weren't even sure anyone would give a shit once we did launch. I couldn't afford to spend time writing automated tests around code that wasn't validated from a business standpoint.
Fortunately for us, people did care, and we grew very quickly before being acquired by Rally Software in early 2010.
I am a firm believer that if I had stuck to "best practices" and maintained the tests while trying to get our product to market quickly, we may not have succeeded in the fashion we did.
This disconnect between your post and my personal experience leads me to believe what I originally said on Twitter: if you really believe that TDD is a requirement for a startup to be successful, I don't think you've ever really experienced what it's like to work in a startup.
And, for the record: I would never hire anyone who insisted on practicing TDD without enough pragmatism to consider the cost versus the value, and time the introduction of automated tests appropriately.
TDD helps make your code better. In your case, it sounds like the key criterion was not that the code work well, but that it let you validate your belief in its business value, with the minimal possible time/money investment. I would agree TDD wasn't applicable, because it didn't provide the specific value you needed.
I would say, though, that once you reach the point where good code becomes important (and even startups face that need), TDD can help you write better code in less time with less effort. Please note the use of "can help"; IMHO neither TDD nor any other methodology will guarantee success.
The earlier startups ('76 and '87) gave me the experience of what a startup is like. I _was_ the warrior god. I worked 60, 70, 80 hours per week. I _knew_ I could overcome all. In one case it worked, and in another it failed.
By relfecting on those experiences, and many other experiences in companies large and small I have since learned a great deal about programming; and about human nature. One of my greatest realizations is that you cannot go fast by rushing. Every shortcut you take slows you down. Every attempt at cutting corners, adds more corners. And so I adopted the mantra: "The only way to go fast is to go well."
In 2002, when I started the FitNesse (fitnesse.org) project, TDD was the rule. I didn't know how well it would work, because I was very new to TDD at the time. But since the risk was low, I gave it a shot. It succeeded beyond my expectations, both as a programming discipline, and also as an open source project. The power TDD gave us (and still gives us) to keep the code clean and under control is something I'd never experienced in any other project. It was profound. It was powerful. It allowed us to go fast, and _keep_ going fast because the code stayed clean. I have come to view it as a moral imperative. No project team should ever lose control of their code; and any slowdown represents that loss of control.
I have since consulted on many projects using TDD, and have helped many others to adopt it. My son, Micah, who was the lead programmer on the FitNesse project, continued to practice TDD in other projects for clients of my company, with great success. When he founded his own company, 8thLight.com, TDD was a founding principle.
When it came time for me to start another company, (cleancoders.com) TDD was, and has remained, a founding principle. TDD keeps the code under control. That control keeps me going fast. I can't imagine surrendering control of the code ever again.
There's an old saying: "Your true beliefs are exposed under pressure." I'm glad your AgileZen story had a happy ending; but I think you got lucky. When the pressure came, your true beliefs came out, and they did not include TDD. You abandoned the discipline because you thought it was slowing you down. And now you are communicating that meme to the world at large. That's a shame.
As long as someone thinks TDD will slow them down, they will abandon it whenever the pressure is high enough. I, on the other hand, know that TDD speeds me up. So when the pressure comes, I hold to my discipline.
I know I can't convince people that TDD will speed them up. But as I look out over the industry from my rather long perspective, I see the change rolling across it. TDD was unknown in 1999. It has gained in awareness and adoption every year since that time. The momentum continues to build.
In another 10 or 15 years TDD will likely be as prevalent and important to programmers as hand-washing is to surgeons or double-entry bookkeeping is to accountants. I stand a good chance of seeing that happen.
I think that TDD works great only when you have a clear idea of what you're building.
I think that TDD is probably not appropriate for a team that is still trying to figure out what they should be building. Software needs to be incredibly malleable at this stage, and the developers can expect to be constantly refactoring and throwing away big chunks of code. Most early-stage startups find themselves in this situation, this is why you are getting so much pushback here.
But yes, once you have a solid vision of what software should be, TDD will help the software stay true to that vision.
I agree that in a startup software needs to be incredibly malleable, and the developers can expect to be constantly refactoring and throwing away big chunks of code. That's precisely what TDD helps you do. You _can not_ refactor without a suite of tests to protect you; all you can do is hack.
If you need your code to be malleable, for God's sake make sure you have a suite of tests you trust with your life. Otherwise you'll be slowed down by the fear that you'll break the code.
Actually, TDD is the way you figure out what you are building. People who start with a solution in mind may write tests first, doing a kind of pseudo-tdd, but they are not reaping the benefits of letting the requirements drive the design.
This is NOT TDD:
1 - Think of a solution
2 - Imagine a bunch of classes and functions that you just know you’ll need to implement (1)
3 - Write some tests that assert the existence of (2)
4 - Run all tests and fail
5 - Implement a bunch of stuff
6 - Run all tests and fail
7 - Debug
8 - Run the tests and succeed
9 - Write a TODO saying to go back and refactor some stuff later.
I don't think we necessarily disagree. In the blog post, it looks like the author was training people on "true" TDD by using pair programming and a simple game like tic-tac-toe or rock-paper-scissors as the "target". This worked because teams were using TDD to evolve their design into something that they already knew pretty well.
I have been practicing TDD since 1999; and have found very few situations in which it does not help me be both better and faster at my job. I would certainly never hire anyone who did not practice it.