$ sudo apt-get update
$ sudo apt-get install libplack-test-externalserver-p

libplack-test-externalserver-p is installed in your system.

Make ensure the libplack-test-externalserver-p package were installed using the commands given below,

$ sudo dpkg-query -l | grep libplack-test-externalserver-p*

You will get with libplack-test-externalserver-p package name, version, architecture and description in a table

libplack-test-externalserver-p package basic information: