Mandriva Linux (ID: mandriva) is one of the distros with a reliable ID. A testcase should be added.

If you want to help, it is sufficient to post to this issue:

• The content of the /etc/os-release file, if any.
• The file names and content of the /etc/*release and /etc/*version files, if any.
• The output of the command: lsb_release -a, if available.