vbe is correct to ask for ownership and permissions on /opt/test.
Just a little background, any time you create a new file or directory UNIX/Linux sets the ownership to the user id and group id of the user creating the file. The permissions that vbe mentions are if you can read, write, or execute the file. These are set to a default value that is part of your environment.
Here is a few commands that you might be interested in:
chown - changes the ownership of a file for user id.
chgrp - changes the ownership of a file for group id.
chmod - permission of files.
umask - default permissions for newly created files.