This kind of categorising I've always found to be orthoganal to what should really be the measure of "does it deserve a [unit] test?" . I believe the correct way to assess how much (if any) automated testing at whatever level is decided only by how valuable that thing, and the inverse of the impact of that thing going wrong, is.
If you are writing on one shot script to transmute data from one format to another for say an upgrade, I don't care if you have unit tests if I am confident it has been manually tested to satisfaction. No repeatability, no regression requirement. There could and likely is value in TDD so tests might still be a thing if that is how you work. No objection there.
If you are developing the plumbing code that will ensure my system adheres to financial regulations and, if it were to break, land me in jail for negligence, you can be damn sure I'm demanding a test that will be run everytime that system is built/deployed.
I wrote unit tests >10 years ago for formatting a string for postal codes that I know are still run to this day on every commit because if they get it wrong there is legal recourse for the company that owns that system.
It's also super quick to fix and failing at build is quicker and cheaper than failing in prod, even without the recourse. That test took me all of 1 minute to write. Bargain.
> I wrote unit tests >10 years ago for formatting a string for postal codes that I know are still run to this day on every commit because if they get it wrong there is legal recourse for the company that owns that system.
If it's critical for your business I'd categorize that as business logic, not plumbing code, well deserving of unit test coverage.
> I believe the correct way to assess how much (if any) automated testing at whatever level is decided only by how valuable that thing, and the inverse of the impact of that thing going wrong, is.
Unit tests and automated tests are two completely different concept.
If you are writing on one shot script to transmute data from one format to another for say an upgrade, I don't care if you have unit tests if I am confident it has been manually tested to satisfaction. No repeatability, no regression requirement. There could and likely is value in TDD so tests might still be a thing if that is how you work. No objection there.
If you are developing the plumbing code that will ensure my system adheres to financial regulations and, if it were to break, land me in jail for negligence, you can be damn sure I'm demanding a test that will be run everytime that system is built/deployed.
I wrote unit tests >10 years ago for formatting a string for postal codes that I know are still run to this day on every commit because if they get it wrong there is legal recourse for the company that owns that system.
It's also super quick to fix and failing at build is quicker and cheaper than failing in prod, even without the recourse. That test took me all of 1 minute to write. Bargain.