Unit testing, Test Driven Development (TDD)

It still amazes me that there are so many projects out and about that have lots of lines of code, interoperating, and communicating systems, and no unit tests.

I don't know how projects get out in time, or even slightly slipping without having any confidence as to how much of the solution actually works.

I would have expected all greenfield projects, and some new additions to software to be able to be built using TDD, and be able to be refactored, and for delivery of the project to be able to be done with confidence.

I know that it often scares people to be using MVC and MVP patterns and dependency injection, but I know that it would scare me more to be in charge of a project that didn't have any unit testing.

Another thing, of projects that I have worked on that have had unit tests, they're often not unit tests, and are instead system or integration tests. Who cares what they are, right? If you run an integration test, and the server goes does, does that mean that your code has failed to pass its requirements? Will it take you an age to figure out if the problem is environmental including lots of debugging, and so on? Quite possibly, as there's so much involved in the real system, so many dependencies. Ultimately you need those tests, but to be able to write solid code, unit tests are what you need.

What else intrigues me is that you hear so many people talking Agile, and yet so few actually show any evidence of being capable of doing it. It seems implausible to run an agile project without unit tests to constrain your planned and unplanned changes to code.

I heard often of people complaning that test driven development takes a lot of overhead, well yes it does, but in the long term, that will mean less time to finish the project, unless it is the most simple project you've ever seen, and even then, I think you could argue a good case for TDD.

I know there are people out there who use Agile and TDD type methodologies, please show yourselves, and make yourselves known to me, and to the world at large!