Problem with ash -n non-zero length string test

[Dallas Clement]

Hello All,

I'm experiencing some weird things when trying to use -n to test for a
non-empty string as in the following example.

boot_drive_name=""

if [ -n $boot_drive_name ]; then
   retval=0
else
   echo "Could not determine boot drive name."
fi

To my surprise, this condition evaluates true and I do not see my echo
message.

However, if I use the -z test, with the following logic, I do see my
echo message.

boot_drive_name=""

if [ -z $boot_drive_name ]; then
   echo "Could not determine boot drive name."
else
   retval=0
fi

I'm not sure if -n does not work 100 percent of the time in all cases or
if it is an erratic problem that only happens under certain conditions.
I have seen it fail in several different logic scenarios.

Has anyone else observed this?  Am I doing something wrong?

I'm seeing this on busybox 1.6.0