Re: [PATCH] tests: add extra protection against unexpected exits

[Jim Meyering]

On Wed, Jan 14, 2015 at 1:24 AM, Bernhard Voelker
<address@hidden> wrote:
> On 01/14/2015 02:51 AM, Pádraig Brady wrote:
>> On 13/01/15 08:13, Bernhard Voelker wrote:
>>>   expectExit 1 program ... || fail=1
>>
>> Very good suggestions.  I implemented the simplification wrapper
>> (I called it returns_), and that in turn made a syntax check feasible.
>
> great, 'returns_' is a much better name, thanks.
>
>> From 92288f467759f84674bf00d2ffe8e4419347f46c Mon Sep 17 00:00:00 2001
>> From: =?UTF-8?q?P=C3=A1draig=20Brady?= <address@hidden>
>> Date: Tue, 13 Jan 2015 03:30:33 +0000
>> Subject: [PATCH] tests: add extra protection against unexpected exits
...
>> --- a/tests/dd/misc.sh
>> +++ b/tests/dd/misc.sh
>> @@ -40,7 +40,7 @@ dd status=noxfer status=none if=$tmp_in of=/dev/null 2> 
>> err || fail=1
>>  compare /dev/null err || fail=1
>>  # check later status=noxfer overrides earlier status=none
>>  dd status=none status=noxfer if=$tmp_in of=/dev/null 2> err || fail=1
>> -compare /dev/null err && fail=1
>> +test -s err || fail=1
>
> nice one!

Actually, I prefer the former.
When some program produces unexpected output, that use of
compare-vs-/dev/null will ensure that the surprising output is
printed in the test's output. If you use only the "test -s err",
you would have to instrument and rerun in order to see
the offending output.