You're essentially in prototyping phase. Inevitably you'll have to discard whole chunks of code, because your understanding of requirements/concept space changes. Then you have to discard both your code and your fine tests, wasting ~2x more time.

Yes, but writing tests isn't a huge cost if you're used to it. And once I've discarded that huge chunk of code, I immediately know what else I broke, rather than having to find it by testing manually.

If I have to write 100 lines of code to implement a feature, it really doesn't take me twice as long to write another 100 to test it. In most cases, writing the test alongside (or even before) the code helps with writing the code. I'd say writing a test adds maybe 25% to the time.

Knowing a year later than that code is still good, because that test still runs successfully, is easily worth that 25%

Of course I'm not saying 100% code coverage is worth it. Just the critical bits.

Thoughts of "a year later" and MVP mostly don't mix.

Agreed about coverage.

Test suite is not free to create or maintain. To your example, for a product that isn't mature, a UI test suite is a waste of time and greatly increases the cost of UI changes.

This is what I don't get - a test suite saves me time. So, yes, it is free to create and maintain. Because it's much quicker to find regression bugs with automated testing than with manual testing. And this is massively more valuable when things are changing rapidly.

I think the core of what they're trying to get at is: let the users find those bugs. The business isn't large enough to focus on details, yet. In the future, when fixing bugs takes more time than making features, you should have the money to hire more hands and focus more on testing. If you don't, then you built too much product for too little clients which is a problem in and of itself ;-)

The cost/benefit isn't there in the beginning. All the bugs are either obvious, easy to find, or quickly discovered without a test suite. So save the time writing tests to stamp out more features the customer wants!

Adding features adds complexity. Features interact with each other in complex ways. If you add a feature and don't know quickly if it broke another feature, that costs time.

Letting the users find the bugs costs time - you have to talk to the user, replicate the bug report, find the failure, fix it, and then release. Finding that same bug 2 minutes after you wrote it (and before it got released) is massively quicker.

This feels like one of those "write code 16 hours a day to make more progress!" things that experience has taught me just doesn't work in practice. I feel like I'm making a lot of progress, but after about 10 hours most of the code I write is pure shite and needs to be rewritten the next day. I've found that it's actually way faster to quit coding after 8-10 hours rather than spend 2 hours the next day rewriting everything I wrote in the last 6 hours the day before.

> finding that same bug 2 minutes after you wrote it (and before it got released) is massively quicker.

That's not realistic.

Your last paragraph about overwork seems unrelated to TDD dogma.

That's because I was relating my personal experience building MVPs rather than spouting TDD dogma.

Tests cost money up front. Can you pay for those tests? You said you will pay for it in decreased costs once the business is running well.

Ok but how confident are you that your business will work out?

1%? you just increased your project costs 100 fold by doing tests.

50%? you just doubled your project costs by doing tests.

100%? Ok you are saving money, but if you are that confident then why haven't you gotten investors aboard that are convinced that doing it well from the start is a business edge?

The mindset and goals are much different. At the extreme, a showstopper bug in an MVP is not a big deal - you have few (if any) customers and a glitch here and there won't make any difference in the long run.

Early stage tech founder should be either a cowboy programmer or a business-minded project manager, the type who ruthlessly kills projects and blows things up on a whim.

That's completely dependent on what kind of software you are writing. (And yeah, if you caught yourself automating UI tests, you are probably way too far.)

The best phrasing is the OP's in that "automated tests are anticorrelated to success" (so is posting on HN, by the way). That doesn't mean that for your exact case they are not essential, just that there is an statistic relation.