[libvirt] [PATCH] build: rewrite test to match change in behavior

[Eric Blake]

On 08/19/2011 08:58 AM, Eric Blake wrote:
>   # Succeed, now: first shut down, then undefine, both via name.
> -$abs_top_builddir/tools/virsh -q -c test:///default 'shutdown test; undefine test'>  out 2>&1
> -test $? = 0 || fail=1
> -cat<<\EOF>  exp || fail=1
> +$abs_top_builddir/tools/virsh -q -c test:///default \
> +    'shutdown test; undefine test; dominfo test'>  out 2>  err

Aargh - this points out a bug in virsh - we aren't calling fflush() in 
between writes to stdout and stderr.  If those two FILE* are mapped to 
the same underlying file description (as is the case when you do 2>&1 
redirection from the shell), then it is essential to flush in between 
every transition between the two FILE* if you want the output to appear 
in linear order.  Without patching virsh, I had to split this into 
capturing output in two files, with no sense of relationship between 
timings, because my test run happened to flush stderr prior to stdout 
and reverse the output from the expected linear ordering of when it was 
produced.

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org