Surprisingly, it works at first launch (I used a simplified version to avoid having to create a file to be read):

$ perl -e '
 use strict;
 use warnings;
 use My::Package (keys %My::Package::); # 

 test("hello world\n");
 test_2("hello this is dog");
'
hello world
hello this is dog
[download]

But I am of course not saying it is a good idea to do that.