diff --git a/test.pl b/test.pl
index f663f2c..7de15ab 100644
--- a/test.pl
+++ b/test.pl
@@ -3,12 +3,13 @@ use 5.22.0;
 
 package Module;
 use Moose;
+use Module::CoreList;
 
 has 'name' => (is => 'ro');
 has 'version' => (is => 'ro');
 
 has 'depends' => (
-    default => sub {my $self=shift; get_deps($self->name)},
+    builder => 'get_deps',
     is => 'ro',
     isa => 'ArrayRef[Module]',
     lazy => 1,
@@ -27,14 +28,26 @@ sub new_module {
     $cache{$name} = Module->new(name => $name);
 }
 
-sub get_deps {
+sub _is_core {
     my $module = shift;
+    chomp $module;
+    my ($name, $version) = split (/[\-~]/, $module);
 
-    return [] if $module eq 'perl';
+    my $ret = ($name eq 'perl' || Module::CoreList->first_release($name)) // 0;
+
+    return $ret;
+}
+
+sub get_deps {
+    my $self=shift;
+    my $module = $self->name;
+
+    # skip perl, or core modules
+    return [] if _is_core($module);
 
     open(my $ph, "-|", qw/cpanm --quiet --showdeps/, $module);
 
-    return [map {Module->new_module($_)} <$ph>];
+    return [map {Module->new_module($_)} grep {!_is_core($_)} <$ph>];
 }
 
 sub print_deps {
@@ -54,3 +67,4 @@ use Data::Dumper;
 
 my $foo = Module->new_module('Moose');
 $foo->print_deps(0, []);
+