[Toybox] Testing: how to check return code

[enh]

On Wed, Oct 30, 2019 at 11:49 AM Andrew Ilijic <ilijic.andrew at gmail.com> wrote:
>
> Thank you Jarno & enh,
>
> I ended up using the following:
> ```
> testing "with -w - Fail if negative" \
> "$IN && ls -w -5 2> /dev/null ; echo \$? && $OUT" "1\n" "" ""
> ```
> enh, I knew I needed to delay the evaluation of `$?` I just could not
> remember or figure out how to do it.
>
> > cmd1 && cmd2 && echo success || echo epic fail
> Jarno, I had forgotten that usage of the `&&` and  `||` operators. I will use
> it in the future.
>
> Let me know if the following should be its own thread.
> > 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 am with you enh. In this case, I wanted the error code because
> GNU `ls` says the command can exit with { 0, 1, 2 }.
> https://linux.die.net/man/1/ls
> POSIX says exit status is { 0, >0 }
> https://pubs.opengroup.org/onlinepubs/9699919799/
> In this case which specification wins?

they're both true, but the GNU ls is more specific :-)

> enh, the other week you mentioned Android will not use the build if
> there are failing tests.

correct. that's why i'm a bit behind --- xargs is still failing.

> Does the above apply to `TEST_HOST=1
> make tests`? If so, then I will rewrite the test.

not at the moment, no, but you probably want `SKIP_HOST=1` before the
affected `testing` (but on the same line so it doesn't apply to later
instances)?

or fix ls to behave like the host. see grep for a similar example.
(or, generally, grep for `exitval`.)

> ~Andrew