$ sudo apt-get update
$ sudo apt-get install libtest-xml-perl 

libtest-xml-perl is installed in your system.

Make ensure the libtest-xml-perl package were installed using the commands given below,

$ sudo dpkg-query -l | grep libtest-xml-perl *

You will get with libtest-xml-perl package name, version, architecture and description in a table

libtest-xml-perl package basic information: