[Toybox] Testing: how to check return code

[enh]

as someone who likes to see the specific exit value (because it's less
ambiguous when you see it in a failure than "yes" or "ok" or
whatever)...

i suspect the question you have to ask yourself here is "when does
that $? get evaluated?".

as a stronger hint, "do you get different results if you use \$? or if
you use 'quoting' instead of "quoting"?"

this, of course, is the argument in favor of || and && --- you might
have to think more to understand a _failure_ but you don't have to
think much when you're writing it. $? is the opposite.

(some tests will always need $? --- the ones that test specific exit
values like 126 vs 127 or whatever.)

On Wed, Oct 30, 2019 at 6:44 AM Andrew Ilijic <ilijic.andrew at gmail.com> wrote:
>
> While implementing `-w` for the `ls` command, I coded it so that the
> command would fail if the user tried to pass a negative value. I
> wanted to test the return code with a negative argument but could not
> make it work. I am not great at Bash. If anyone can tell me what I was
> doing wrong, I would appreciate it.
>
> ```
> testing "with -w - Fail on negative" \
> "$IN && ls -w -5 > /dev/null; echo $? && $OUT" \
> "1" "" ""
> ```
> The command would fail and return 1 but, in testing it would always
> write zero to the file.
>
> ~Andrew
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