Re: proposal: minscale, rtrim, btrim functions for numeric

po 9. 12. 2019 v 19:15 odesílatel Karl O. Pinc <kop(at)meme(dot)com> napsal:

> Hi Pavel,
>
> I've had some thoughts about the regression tests.
>
> It wouldn't hurt to move them to right after the
> scale() tests in numeric.sql.
>
> I believe your tests are covering all the code paths
> but it is not clear just what test does what.
> I don't see a lot of comments in the tests so I don't
> know that it'd be appropriate to put them in to
> describe just what's tested. But in any case it
> could be nice to choose values where it is at least
> sort of apparent what part of the codebase is tested.
>
> FWIW, although the code paths are covered, the possible
> data permutations are not. E.g. I don't see a case
> where scale > 0 and the NDIGITS of the last digit is full.
>
> There are also some tests (the 0 and 0.00 tests) that duplicates
> the execution path. In the 0 case I don't see a problem
> but as a rule there's not a lot of point. Better test
> values would (mostly) eliminate these.
>
> So, my thoughts run along these lines:
>
> select minscale(numeric 'NaN') is NULL; -- should be true
> select minscale(NULL::numeric) is NULL; -- should be true
> select minscale(0); -- no digits
> select minscale(0.00); -- no digits again
> select minscale(1.0); -- no scale
> select minscale(1.1); -- scale 1
> select minscale(1.12); -- scale 2
> select minscale(1.123); -- scale 3
> select minscale(1.1234); -- scale 4, filled digit
> select minscale(1.12345); -- scale 5, 2 NDIGITS
> select minscale(1.1000); -- 1 pos in NDIGITS
> select minscale(1.1200); -- 2 pos in NDIGITS
> select minscale(1.1230); -- 3 pos in NDIGITS
> select minscale(1.1234); -- all pos in NDIGITS
> select minscale(1.12345000); -- 2 NDIGITS
> select minscale(1.123400000000); -- strip() required/done
> select minscale(12345.123456789012345); -- "big" number
> select minscale(-12345.12345); -- negative number
> select minscale(1e100); -- very big number
> select minscale(1e100::numeric + 0.1); -- big number with scale
>
> I don't know why you chose some of your values so if there's
> something you were testing for that the above does not cover
> please include it.
>
>
some values was proposed in discussion, others are from tests of scale
function.

I used proposed tests by you.

Regards

Pavel

> So, a combination of white and black box testing. Having written
> it out it seems like a lot of testing for such a simple function.
> On the other hand I don't see a lot of cost in having all
> these tests. Opinions welcome.
>
> Regards,
>
> Karl <kop(at)meme(dot)com>
> Free Software: "You don't pay back, you pay forward."
> -- Robert A. Heinlein
>