Perl has no idea it's suppose to call test as a method.

The only difference between a function and a method is how the sub is called, or rather, how it expects to be called.

test()           # function
Module::test()   # function
$obj->test()     # virtual instance method
$class->test()   # static method
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Non-virtual instance methods can be approximated using

test($obj)         # From within the object that defines test().
  -or-
Class::test($obj)  # From anywhere.
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I say "approximate", since it's doesn't check inheritance.

And there's also this syntax:

$obj->Class::test()
$class->Class::test()
$obj->SUPER::test()
$class->SUPER::test()
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In this case, all of the following work:

sub eg { $_[0]->test($_[1]); }
sub eg { One::test(@_); }
sub eg { Two->test($_[1]); }
sub eg { One->test($_[1]); }
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Only the first really makes sense, though. And maybe the second one if you don't want test to be overridden by a child class of Two.