Here's why: "Shipping is a feature. A really important feature. Your product must have it."
Dave Drake sent the link along with the following:
This "speaks of coding for the rest of us, who are not into building castles in the air, but getting the job done. Not that there is anything wrong with better design, cleaner APIs, well-defined modularity to ease the delegation of coding as well as post-delivery maintenance. But damn, I wish I had a nickel for every time I sat in a design meeting where we tried to do something the fancy way, and it broke in the middle of the development cycle, or testing, or even the builds, and always in the demos."
There is one set of quotes that falls somewhere on the continuum of wrong, misleading and flamebait.
"And unit tests are not critical. If there’s no unit test the customer isn’t going to complain about that."
This -- in my experience -- is wrong. For Joel or the author of the quote (Jamie Zawinski) this may be merely misleading because it was taken out of context.
It's absolutely false the customers won't complain about missing unit tests. When things don't work, customers complain. And one of the surest ways to make things actually work is to write unit tests.
I suppose that genius-level programmers don't need to test. The rest of us, however, need to write unit tests.
Unit Testing Dogma
On Stack Overflow there are some questions that illustrate the value of misinformation on unit testing. On one end, we have Zawinski (and others) who says that Unit Tests don't create enough value. On the other end we have questions that indicate the slavish adherence to some unit test process is essential.
See How to use TDD correctly to implement a numerical method? The author of the question seems to think that TDD means "decompose the problem into very small cases, write one test for each very small test, and then code for just that one case and no others." I don't know where this process came from, but it sounds like far too much work for the value created.
It's unfair to say that unit testing doesn't add value and claim that customers don't see the unit tests. They emphatically do see unit tests when they see software that works. Customers don't see unit tests in detail. They don't see dogmatic process-oriented software development.
When there are no tests, the customer sees shoddy quality. When the process (or the schedule) trumps the feature-set being delivered, the customer sees incomplete or low-quality deliverables.
The original blog post said -- clearly -- that gold-plated technology doesn't create any value.
The blog post also pulled out a quote that said -- incorrectly -- that unit tests doesn't create enough value.