testdrive sets wrong MEM value

I have testdrive 1.15-0ubuntu1~ppa4 installed, and it ends up passing 256 MB of memory when starting kvm if I set MEM in the config file, due to the code:

[ -z "$MEM" ] && [ $(grep "^MemTotal" /proc/meminfo | awk '{print $2}') -gt 1000000 ] && MEM=512 || MEM=256

the && and || operators are left-associative and have the same priority in shell, so this is evaluated as:

( ( [ -z "$MEM" ] && [ $(grep "^MemTotal" /proc/meminfo | awk '{print $2}') -gt 1000000 ] ) && MEM=512 ) || MEM=256

and the initial -z $MEM test ends up being false, so the expression falls through to the MEM=256 part.

I think the fix for this is to rewrite the expression as:

[ -z "$MEM" ] && { [ $(grep "^MemTotal" /proc/meminfo | awk '{print $2}') -gt 1000000 ] && MEM=512 || MEM=256 ; }

ie only do the whole "check MemTotal and default MEM based on that" thing if MEM isn't set in the first place.

Or perhaps make it more explicit and do

if [ -z "$MEM" ]; then
        [ $(grep "^MemTotal" /proc/meminfo | awk '{print $2}') -gt 1000000 ] && MEM=512 || MEM=256
fi