[LTP] Failing test on failing shell commands

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
> I have a failing memcg_use_hierarchy_test (in
> testcases/kernel/controllers/memcg/functional/) which hits unexpected
> OOM on one of earlier commands, already in the test:
> 
>  18         echo 1 > memory.use_hierarchy
>  19         echo $PAGESIZE > memory.limit_in_bytes
>  20 
>  21         mkdir subgroup  
> mkdir: cannot create directory ???subgroup???: Cannot allocate memory
> /home/ubuntu/ltp-install/testcases/bin/memcg_use_hierarchy_test.sh: 22: cd: can't cd to subgroup
> 
> The command did not fail, as there is no "set -e" and test fails later.
> However there could be a case where such failure does not trigger later
> issue and test is a false-positive.
> 
> What is the practice for LTP shell tests to handle kind of preparation
> commands? Maybe this should be something like:

We do have ROD (as a shorthand for "run or die") in the shell test
library, so this really should be:

	ROD mkdir subgroup

-- 
Cyril Hrubis
chrubis@suse.cz