What you describe is the typical mindset against TDD, it's difficult to explain the benefits, and really you just have to experience them for yourself. Changing your mindset is difficult, I know, why change what works right? My only tip is to keep an open mind about it, as TDD benefits are often not apparent to begin with, they only come after a couple of days work or weeks or months later or even years later.

You find that you need to do less mental work, as your tests make the required abstractions apparent for you. 'the minimum thing that makes the test pass' ends up being the complete solution, with full test coverage. Any refactoring done is safe from regressions, because of your comprehensive test suite. And when other colleagues inevitably break your code, you already have a test lying in wait to catch them in the act.

> Any refactoring done is safe from regressions, because of your comprehensive test suite.

As much as I like the idea of TDD, I have a problem with this part. When some refactoring is needed, or the approach changes, it seems like you have two choices. One is to write the new version from scratch using TDD. This wastes extra time. The other is to refactor which breaks all the guarantees you got before. Since both the code and the tests are changing, you may lose the old coverage and gain extra functionality/bugs.

And unfortunately in my experience, the first version of the code rarely survives until the deployment.

I'm not sure what approach you've described here, but it isn't TDD. In the case of adding new features to existing code, as you are continually running tests you will know straight away which you have broken. At this point you would fix them so you get all green again before continuing. In this way you incrementally modify the codebase. Remember unit tests are quite simple 'Arrange, Act, Assert' code pieces, so refactoring them is not a time sink.

refactoring != adding new features.

Also some refactorings are easier with tests, some are harder.

The kind @viraptor mentiones is the kind that spans more than one compoment. For example when you decide that a certain piece of logic was in the wrong place.

The kind of refactoring that becomes easier is when you don't need to change the (public) API of a component.

Take for example the bowling kata. If you want to support spares and strikes and you need extra bookkeeping, that's the easy kind of refactor where your tests will help you.

But if so far you have written your tests to support a single player and now you want to support two players who play frame by frame... Now you can throw away all the tests that affect more than the very first frame. (yes in the case of the bowling kata, you can design with multiple players in mind, but that's a lot harder in the real world when those requirements are not known yet)

> What you describe is the typical mindset against TDD, it's difficult to explain the benefits, and really you just have to experience them for yourself. Changing your mindset is difficult, I know, why change what works right? My only tip is to keep an open mind about it, as TDD benefits are often not apparent to begin with, they only come after a couple of days work or weeks or months later or even years later.

I've been forced to follow TDD for several years and also been given the same kind of comments to downplay any reasoned arguments against it which I find frustrating to be honest. I don't see why the benefits wouldn't be immediately apparent.

> You find that you need to do less mental work, as your tests make the required abstractions apparent for you. 'the minimum thing that makes the test pass' ends up being the complete solution, with full test coverage. Any refactoring done is safe from regressions, because of your comprehensive test suite. And when other colleagues inevitably break your code, you already have a test lying in wait to catch them in the act.

You can do all of the above by writing tests at the end and checking code coverage as well.

"Any refactoring done is safe from regressions, because of your comprehensive test suite. "

With the right tests this works great. I have also seen the opposite where a test suite was extensive and tested the last details of the code. Then the refactor needed more time to figure out what the tests are doing than the actual refactoring. As often, moderation is the key to success.

Unit tests should follow a simple 'Arrange, Act, Assert' structure and test one single thing, described in it's title. I agree anything too complicated starts to defeat the point, especially when we are mainly after a quick feedback loop.

How to implement an SDK that performs real-time manipulation of audio without really knowing how to describe the correct result using TDD?

Only when I understand the problem, the SDK and the expected result I could start writing some tests.

TDD seems to be for business applications where you're using tried and tested technology to implement new problems.

> it's difficult to explain the benefits, and really you just have to experience them for yourself. Changing your mindset is difficult, I know, why change what works right? My only tip is to keep an open mind about it

Scientologists make the same argument

Maybe writing code for exploration and production should be considered separate activities? The problem with these coding ideologies is that they assume there is only one type of programming, which is BS, the same as assuming a prototype is the same as a working product.

What's exploratory programming though? Unless you're writing something that's very similar to something you've written before and understand it well, most programming involves a lot of exploration.

Well, UX prototypes for one. In research, most projects never go into production, those that do do so without researcher code. Heck, even in a product team, if you are taking lots of technology risks in a project, you are going to want to work those out before production (and it isn’t uncommon to can the project because they can’t be worked out).

To be fair, TDD is quite good for exploratory programming, as it makes you think about the intent or your API up front.

Not really. It makes you commit to an API upfront, this is the exact opposite of what exploratory programming should be (noncommittal, keep everything open).

No with TDD you don't need to go in with a structure in mind, the structures arise as you write more tests and get a proper understanding of what components you'll require. Red, green, refactor - each refactor brings you closer to the final design.

That's the mantra often quoted but it always makes me think of the famous Sudoku example from Ron Jeffries. Basically as a mantra it falls down if you don't understand the problem domain. It's popular because it works for the sort of simple plumbing that makes up a lot of programming work. This problem is particularly true for anything creative you're trying to express as the requirements are often extremely fuzzy and require a lot of iteration.

If you don't know how to solve a problem you actually need to do some research and possibly try a bunch of different approaches. Over encumbering yourself with specific production focused methodologies hurts. If you're doing something genuinely new this can be months of effort.

After the fact you should go back and rewrite the solution in a TDD manner if you think it benefits your specific context.

> After the fact you should go back and rewrite the solution in a TDD manner if you think it benefits your specific context.

Why? Why not add tests to your existing code?

Because it was never meant for production at all.

That really isn’t exploratory programming. The end result should be code that you throw away en masse (it should in no case reach production). Otherwise, production practices will seep in, you’ll become attached to your code and the design it represents, hindering progress on the real design.

When I was a UX prototyper, none of my code ever made it into production.

>I find when you're writing tests first, you're being forced to write code without understanding the problem space yet and you don't have enough code yet to see the better abstractions.

That's why it's better to start with the highest level tests first and then move down an abstraction level once you have a clearer understanding of what abstractions you will need.

Can you do that with TDD though? Why not just sketch the code out first before you start writing tests?

I find TDD proponents don't take into account that writing tests can actually be really time consuming and challenging, and when you've got a lot of code that is tests, refactoring your tests becomes very tedious.

You can do that with TDD (it's called outside-in), although I agree that it is time consuming and challenging, especially without the right tools.