[prerok]

Indeed, they are two separate concepts.

I write lots of automated tests, but almost always after the development is finished. The only exception is when reproducing a bug, where I first write the test that reproduces it, then I fix the code.

TDD is about developing tests first then writing the code to make the tests pass. I know several people who gave it an honest try but gave up a few months later. They do advocate everyone should try the approach, though, simply because it will make you write production code that's easier to test later on.

[computerdork]

... hmm, just looked it up. According to some sites on the web, TDD was created by Kent Beck as apart of Extreme Programming in the 90's and automated testing is a big part of TDD. Having lived through that era, thinking back, would say that TDD did help to popularize automated testing. It made us realize that focusing a ton on writing tests had a lot of benefits (and yeah, most of us didn't do the test first development part).

But this is kind of splitting hairs on what TDD is, not too important.