Mine is that a lot of potential errors (typos, type mismatches) don't need to be exercised by running code in typed language.
Yours is... well, you don't really address it.
If you're not, that suggests you're not doing them right which in turn suggests why you might have an issue with them...
I suppose you could do something like, enumerate every possible combination of inputs and check that some property holds for all of them. Or, maybe you could instead randomly select a number of combinations of inputs and check that a property holds for each of those random combinations, but that wouldn't be guaranteed to find the inputs for which the specification isn't satisfied.
I guess maybe if the test passed to the function to be tested, mock values, such that the function is effectively evaluated symbolically (where any branching that depends on the inputs to the function, would maybe have the mocked object specify what the result of the conditional should be, with different tests for different cases?) ?
Or.. Can you explain how you write tests such that they truly function as specifications?
You should be able to find a property testing library in your favourite language such as Hypothesis (python), Quickcheck (Haskell), Fastcheck (JS/typescript), etc.
Where X, Y and Z are very specific.
These example scenarios work well as a communication medium for discussing intended program behavior as well as translating well into tests.
>enumerate every possible combination
Whereas if you start doing this you will probably confuse your stakeholders.
Specific examples tend to make better specifications.
That to me doesn’t seem like what a “specification” is.
Now, maybe having good examples is more important for business use cases than having a specification.
But I generally wouldn’t call it one.