#!/usr/bin/perl
use strict;
use warnings;
use List::Util qw(sum);

while (<DATA>)
{
   my ($var) = /:\>\>(\w+)/;  # could have been done
   my (@nums) = /,\s*(\d+)/g; # on one line... 
   
   next unless $var;  # skips bogus lines
  
   print "$var,",sum(@nums),"\n";
}

#prints:
#test,10
#test1,26


__DATA__
<"Session Date:Mar 13/2017 
":>>test", 1,2,3,4 
":>>test1", 5,6,7,8 
end>