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I feel like I'm in crazy town in this thread. Most of the replies seem to be misunderstanding the intent of TDD, and yours is one of the few that gets it right.

I feel like I'm in crazy town in this thread. Most of the replies seem to be misunderstanding the intent of TDD, and yours is one of the few that gets it right. Is general understanding of TDD really that far off the mark? I had no idea, and I've been doing this for essentially 2 decades now.

pjmlp 4y ago
No we really understand that the whole religion of only writing code after a failing test only applies to niche cases of libraries for headless applications in monoliths. Lets say my designer came to me and now wants bump mapped textures on engine, well I cannot touch that compute shader without writing a test first, so suggestions for a TDD framework for GPU shaders.
- pydry 4y ago
  Ive done a form of TDD where I have a test scenario set up that generates a picture and I tweak the code until the picture looks right and then "freeze" it. Once frozen the test compares the picture (or other artefact) against the generated picture (or artefact). Im not sure if it'd be useful in your situation though.
  - pjmlp 4y ago
    Now apply that to a full native GUI application, while keeping in synch with UI/UX requirements and the rule of no code without failing tests.
    - pydry 4y ago
      Yeah, Ive kind of done this. The code changes that changed the UI - even changing some CSS - would cause a screenshot comparison failure on certain steps in the test. If it is what was expected then we overwrote the old screenshot with a new one. It isnt exactly the same as the TDD process coz sometimes you write the code first (e.g. CSS), eyeball it and then rebuild the screenshot if it looks correct. I'd say it's close enough though. I wont pretend it worked perfectly. The screenshot comparison algorithms were sometimes flaky and UIs can be surprisingly non-determinstic and you need to have a process to pull the database and update screenshots accordingly. However, it's the approach I'd prefer to take in the future (I havent done UIs for about 3 years now). I also wasnt religious about covering every single scenario with tests but I could have been. The company moved fast and sometimes they just wanted quick and not reliable.
      - pjmlp 4y ago
        That is the whole deal, it was Web, so kind of easier than native, given its source based form, and even then, you had to bend the rules from TDD religion.
        switchbak 4y ago
        I think you're being a little uncharitable to the TDD folks here. Sure the early writing was very dogmatic, but real world TDD doesn't seem to be to be as rigid as you describe. Or perhaps you've worked with some real TDD zealots, that doesn't sound like fun. The folks I've worked with use these as guiding recommendations, not binding dictates. For some of the UI stuff you mentioned elsewhere, I've seen a stronger focus on testing not just business logic, but view logic as well (where possible), but generally not to the degree of testing the rendered output of the UI. Maybe that's a thing somewhere, but I haven't personally seen it.
        pydry 4y ago
        The same sort of thing should be possible for various kinds of native too. You'll need a selenium-esque library that can interact with UIs and take screenshots in your environment. But yeah, if you dont have one of those tools or its super unreliable or it's only available in a language you cant use then you cant do this. I dont really consider this to be bending the rules of TDD. It's more like next gen TDD IMO.

pjmlp 4y ago

No we really understand that the whole religion of only writing code after a failing test only applies to niche cases of libraries for headless applications in monoliths. Lets say my designer came to me and now wants bump mapped textures on engine, well I cannot touch that compute shader without writing a test first, so suggestions for a TDD framework for GPU shaders.

pydry 4y ago
Ive done a form of TDD where I have a test scenario set up that generates a picture and I tweak the code until the picture looks right and then "freeze" it. Once frozen the test compares the picture (or other artefact) against the generated picture (or artefact). Im not sure if it'd be useful in your situation though.
- pjmlp 4y ago
  Now apply that to a full native GUI application, while keeping in synch with UI/UX requirements and the rule of no code without failing tests.
  - pydry 4y ago
    Yeah, Ive kind of done this. The code changes that changed the UI - even changing some CSS - would cause a screenshot comparison failure on certain steps in the test. If it is what was expected then we overwrote the old screenshot with a new one. It isnt exactly the same as the TDD process coz sometimes you write the code first (e.g. CSS), eyeball it and then rebuild the screenshot if it looks correct. I'd say it's close enough though. I wont pretend it worked perfectly. The screenshot comparison algorithms were sometimes flaky and UIs can be surprisingly non-determinstic and you need to have a process to pull the database and update screenshots accordingly. However, it's the approach I'd prefer to take in the future (I havent done UIs for about 3 years now). I also wasnt religious about covering every single scenario with tests but I could have been. The company moved fast and sometimes they just wanted quick and not reliable.
    - pjmlp 4y ago
      That is the whole deal, it was Web, so kind of easier than native, given its source based form, and even then, you had to bend the rules from TDD religion.
      - switchbak 4y ago
        I think you're being a little uncharitable to the TDD folks here. Sure the early writing was very dogmatic, but real world TDD doesn't seem to be to be as rigid as you describe. Or perhaps you've worked with some real TDD zealots, that doesn't sound like fun. The folks I've worked with use these as guiding recommendations, not binding dictates. For some of the UI stuff you mentioned elsewhere, I've seen a stronger focus on testing not just business logic, but view logic as well (where possible), but generally not to the degree of testing the rendered output of the UI. Maybe that's a thing somewhere, but I haven't personally seen it.
      - pydry 4y ago
        The same sort of thing should be possible for various kinds of native too. You'll need a selenium-esque library that can interact with UIs and take screenshots in your environment. But yeah, if you dont have one of those tools or its super unreliable or it's only available in a language you cant use then you cant do this. I dont really consider this to be bending the rules of TDD. It's more like next gen TDD IMO.