What? So it works in some situations, but not all. Thus hocus?
I'm no 'Agile Testing Expert', but I have worked for the last 2-3 years doing TDD exclusively (as in ALWAYS writing tests first). It isn't hocus. It is effective. I can understand it doesn't suit all problems, and can potentially be a hinderance sometimes, but that is the same for ANY methodology/practice. I don't quite understand your hostility towards it.
What do you mean by 'developer driven testing'?
The hocus is that you must use it, because some guru said so.
Then why do it exclusively?
Testing is about helping developers, and recognizing that automated testing is about benefit to developers, rather than cargo-culting a workflow and decreeing that one size fits all.
Writing tests first as a tool to be deployed where it works is "Developer Driven Testing" - focussing on making the developer more productive by choosing the right tool for the job. Generalizing a bunch of testing rules and saying This Is The One True Way Even When It Isn't (I mean seriously, you continued to use it when it was a hindrance?!) - that's not right.
Sounds like you are interpreting TDD in a rather extreme way. If you haven't found it useful, then fine don't use it. But that doesn't mean it is universally bad, and thus doesn't deserve the "It's all hocus and you are a stupid zealot if you do it"
My experience is the same as (what I believe is) the usual criticism of tests-first.
I often need to rethink the API to my functions/methods, sometimes more than once. This goes for both external and internal APIs, so it doesn't help with detailed interface specifications between modules.
Test-first is a problem, since it needs a fixed interface before I'm ready to lock down the interface.
I tend to instead write inside-out; a few pages of code and then write tests for that code. That model isn't really kosher/halal/etc, according to TDD?
TDD suggests 3 steps: 1. Write one test 2. Write the minimal code to make it pass 3. Refactor the code you've got.
Try not to think of tests as immutable. You can throw away tests when they don't provide value.
Finally, make sure you're using an IDE with refactoring support. That helps immensely when you make an API change which will affect your tests.
Interesting TDD argument. I'll buy a book or something and try again when my present hobby project is done and I have time for experimenting.
(IDE refactoring needs a stricter language than I prefer. Also, without an IDE and using my old eyes I have 2 A4 of code + 1 A4 of bash on a 24" monitor...)
The examples are all Java, but the accompanying website (http://www.growing-object-oriented-software.com/) has links to reimplementations in several other languages.
The point of using TDD to write interfaces is that you first write the code you wish you had, and then implement it. The other way around you could end up with code that is optimized for the code inside the module, and not optimized for using it.
Of course now you have to rewrite your tests and your code when changing an API, but at least you know that no other part of your application got broken by the new API.
I personally like the TDD approach to write interfaces, since then I won't take shortcuts just because it is easier to do in the specific module that I'm programming/extending. It will actually produce code that can be used easily from the outside and removes a lot of dependencies in the process.
Making tests a central part of the process because they're useful to developers? Awesome. Dictating a workflow to developers that works in some cases as the One True Way: ridiculous.
I tend to agree with you that TDD as a development methodology is deeply flawed. I have never found that the act of writing a test case and making it pass has helped me with the actual creative process of solving a problem via code. In fact, I'll frequently dash out a method I'm writing quickly, and then go back and reconstruct it piece by piece via TDD.
The main benefit writing tests first gives you is that you know your test is actually working (i.e. because it first fails) and that the code you implement actually passes it. It also keeps you honest because it prevents you from writing "extraneous" code, i.e. code that exists but is not specified by a test.
So yeah, I totally agree with you that the cult of TDD kind of sucks. But I haven't stumbled upon a better way yet. I've often thought it would be cool if there was some way for e.g. your version control software to be tied to the code you write that passes certain test(s), such that you could somehow verify that without that code your test fails and with that code your test passes. For the present though, TDD tends to work pretty well for me.
Labouring under the idea that Tests Must Come First (and everything I've seen, and everything I /do/ see now suggests that that is the central idea in TDD - you write a test, then you write the code to pass it) without pivoting to see that testing is a useful practice in so much as it helps developers is the wrong approach.
The problem is that ideologies like TDD try to come up with simple rules for how to develop (i.e. always write tests first). In reality, it's better to use your brain when you're deciding how to approach something (i.e. is this a good situation for writing tests first?)
I often code three or four commits worth at once when on a roll and it's a pain doing multiple staged adds, stashes, tests, and commits to store each sub-change on its own. Having a tool to help with this would be great.
For me, TDD, in practice means switching back and forth between writing tests and production code. That is, write some test code, run, fail, fix the production code, write some more test code. It is incremental.
EDIT: Fixed a typo
When you write something you run it to make sure it works. Bottle that and call it a test. And then merely do this before you write the code. "What will I be done when I get this code to do?"
Don't plan, and spec, your whole API before you've written a line of code or anything, but do write a one-liner to check whatever it is you're going to do so you know when you're done.
Ideally you'll write a test (still just a one-liner) for every corner-case that you cover in code, because you need a failing test to know if your fix actually worked.
And face it, if you're doing "real" development work you've got business goals, and a spec with features intended to deliver on that, and you need to cover every tiny detail. If you don't have the spec ('fail on values over n') directly linked to the code that implements it, it will get lost, and if you aren't testing it you can't legitimately claim to be delivering it.
A spec, such as you'd get by performing useful TDD, is a requirement for modern software development. You could write it all up-front in the planning phase (waterfall style), or all after in the testing phase (waterfall style again), or you could interleave it with research and development, which if you think about it, sounds kind of agile by comparison...
Have I had experience (and much value) out of sometimes writing tests for certain problem classes before writing any code? Yes. Changes to existing functionality are often a good candidate.
Does TDD as a methodology suggest you should ALWAYS write your tests first? Everything I've read suggests so.
And "as any fule kno" [sic], this is idioicy during a design or hacking or greenfield phase of development. Allowing your tests to dictate your code (rather than influence the design of modular code) and to dictate your design because you wrote over-invasive test.
tl;dr: Writing tests before code works pretty well in some situations. Test Driven Development, as handed down to us mortals by Agile Testing Experts and other assorted shills, is hocus.