After many failed attempts at TDD, I realized/settled on test driven design, which is as simple as making sure what you're writing can be tested. I don't see writing the test first as a must, only good to have, but testable code is definitely a must.

This approach is so much easier and useful in real situations, which is anything more complicated than foo/bar. Most of the time, just asking an engineer how they plan to test it will make all the difference. I don't have to enforce my preference on anyone. I'm not restricting the team. I'm not creating a knowledge vacuum where only the seniors know how yo code and the juniors feel like they know nothing.

Just think how you plan to test it, anyone can do that.

This reminds me when a senior engineer asked me to write exception handling on a one-off python script, not a production code - just a script devs can use internally. The "handling" was that the program should exit when a file is not found. He wanted me to try the file open, except the file error, print "file not found" message and exit(1).

Guess what, genius. Python already does that for you. No need to write an extra wrapper needlessly.

Also, I hate mocks. I spent so long learning all the test doubles to pass interviews: what’s the difference between a spy, fake, stub, mock, etc.

Oh good grief. I haven't even heard of half of those, and I've been writing code longer than most interviewers.

Also doing it with dependency injection and all that.

After struggling with several DI frameworks, I've come to the conclusion that DI is far too opaque and unpredictable to be useful.

OOP is also intentionally opaque, mind you, but debuggers can see through it if necessary, so that's fine. DI, on the other hand, is opaque even to debuggers!

I much prefer having an in-memory database than mock what a database does.

I much prefer using the same DBMS for tests as the one used in production. That way, I can use its special features (like arrays as query parameters), and avoid bugs resulting from differences between DBMSes (which would only appear in production).

You obviously can’t always get replacements for things and you’ll need to mock and I get that. I just prefer to not use them if I can.

Indeed, and you usually can. Even if your system involves a bunch of services that normally run on different machines, who says you can't spin up instances of them as part of the test? Tests are arbitrary code and can do anything that any other program can do, including starting subprocesses. Just be sure to terminate them once the test is finished, even if it fails.

I like to mock up dependencies with Docker Compose, then run all the tests against that. Keep the compose file in the repo, of course. I don’t tend to build a lot of real unit tests unless I’m doing something very novel and self contained. When you’re just assembling a service out of REST libraries and databases, integration testing is mostly what you want.

Send help? We're all caught in the same fire.

Yep. I’ve been there.

Make it maintainable should be up there too.

I’ve worked with projects that does the right thing, but no one can add new features to it because it’s a nightmare to work with. It’s at the level of not being able to move a button on the UI without breaking how the software interacts with the cloud.

Pick two.

There's some things called software architecture, requirement engineering and software design. More dev teams should try this.

The Test part of TDD isn’t meant to encompass your whole need before developing the application. It’s function-by function based. It also forces you to not have giant functions. Let’s say you’re making a compiler. First you need to parse text. Idk what language structure we are doing yet but first we need to tokenize our steam. You write a test that inputs hello world into your tokenizer then expects two tokens back. You start implementing your tokenizer. Repeat for parser. Then you realize you need to tokenize numbers too. So you go back and make a token test for numbers.

So you don’t need to make all the tests ahead of time. You just expand at the smallest test possible.

You don't write a whole app in tests and then write the whole app in code, you make tests for the functionality as you go.

I don't know if you're joking or not. I suppose tdd will help know what you need before you start.

I think you have a point with the moving target, but also I believe that development should pretty much always be a moving target. You should be refactoring your domain based on new experiences and new knowledge all the time. So, personally, I find integration tests much more useful, because they test the input and output of a system, rather than how it's implemented. I can change my domain without having to modify my tests and that makes changes to the domain much simpler.

That being said, I also definitely recognize the advantages of TDD, I just don't think it's a silver bullet; there's good projects for it and bad ones

Yeah but getting the hang of it is the hard part. I don't know any dev in my company or my circle that uses it; we all did learn about it alright.

It is a lifesaver in some cases

Good way to figure out how an unknown code base works is to add unit tests tho

How does that even correlated?