Just a thought: does the directory ./test exist ??
Also the -o is only needed when specifying options, which you aren't doing...
So drop the -o and maybe use an absolute path...
for example:
first make a directory:
mkdir -p /tmp/mnt/nfs
then mount it to that directory:
mount -t nfs 192.168.2.4:/mnt/array1/Buffalo /tmp/mnt/nfs