Not likely
> Each individual external service will easily have tens of conditions
You will likely not propagate those to the end user, but log and return a single error for many of those cases
> A common misconception, but no.
A common misconception is that tests are documentation in any shape or form.
> Tests would serve no purpose if you had no reason to document expected behaviour.
You do not document behaviour with tests. You write the tests to make sure your app conforms to documented behaviour.
As documentation tests are useless because they are a collection of separate and disparate scenarios and cases lacking any context or continuity. If anyone ends up looking at tests for documentation on how your app or service behaves, I have bad news for you.
> Your documentation doesn't end there
Thts is literally the dead end of documentation. Well, the actual dead end is "code is documentation" and "types are documentation". Neither of them are. Documentation is documentation. Comments are documntation. Design docs and specs are documentation.
Tests, and especially the way most practices propose tests should be written, could not be farther from documentation.
> The invented practices you have presented throughout the discussion no doubt lead to writing useless tests.
Indeed they do.
> It is, however, not clear why you hang on this invention of yours – outright ignoring what you are being given.
So you have fabricated this idea that I am ignoring something and is now attempting to make me defend this fabrication of yours.