Re: [PATCH] tests: use env and support both unbuffer/stdbuf

[Karel Zak <kzak@redhat.com>]

On Tue, Aug 27, 2019 at 02:26:08PM +0200, Patrick Steinhardt wrote:
> Triggered by commit f612c4c67 (tests: fix --unbuffered mode with
> ASAN, 2019-08-27), which says:
> 
>     Well, this patch sucks. It would be nice to have things in
>     the way how it has been original expected by Patrick's patch,
>     but ...
> 
> So this commit here effectively reverts it and instead tries to
> improve the shortcomings of the original patch. First, it uses
> env(1) to set ASAN_OPTIONS instead of directly adding it to the
> args array to fix execution of "${args[@]}" "$@".
> 
> Second, it now supports both unbuffer(1) and stdbuf(1). The
> latter uses LD_PRELOAD tricks, which doesn't play nicely with
> ASAN, so it will not be used if ASAN has been requested. It's
> still valuable to have support for both, as many more systems
> will have stdbuf(1) from coreutils installed but not unbuffer(1)
> from expect.

Applied, thanks.

Unfortunately, it seems result is fragile. It fails on travis
https://travis-ci.org/karelzak/util-linux/jobs/577767328

The problem is the order of some output lines, for example:
tests/output/rename/exit_codes

Maybe the best and most robust solution would be split stdout and
stderr into two files for each test. Now we have $TS_OUTPUT, what about
to replace it with $TS_STDOUT and $TS_STDERR? Something like:

 - $TS_CMD_MOUNT $DEVICE $TS_MOUNTPOINT >> $TS_OUTPUT 2>&1
 + $TS_CMD_MOUNT $DEVICE $TS_MOUNTPOINT >> $TS_STDOUT 2>> $TS_STDERR

And also create tests/expected/<foo>/<bar>{.err} for tests where any
output on stderr is expected, otherwise assume $TS_STDERR is empty.

This change will be pretty invasive, but than we can easily compare 
outputs and keep track about what is where printed. 

    Karel


-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com