--- /dev/null
+use strictures 1;
+use Test::More;
+use Sub::Defer;
+
+my %made;
+
+my $one_defer = defer 'Foo::one' => sub {
+ die "remade - wtf" if $made{'Foo::one'};
+ $made{'Foo::one'} = sub { 'one' }
+};
+
+my $two_defer = defer 'Foo::two' => sub {
+ die "remade - wtf" if $made{'Foo::two'};
+ $made{'Foo::two'} = sub { 'two' }
+};
+
+is($one_defer, \&Foo::one, 'one defer installed');
+is($two_defer, \&Foo::two, 'two defer installed');
+
+is($one_defer->(), 'one', 'one defer runs');
+
+is($made{'Foo::one'}, \&Foo::one, 'one made');
+
+is($made{'Foo::two'}, undef, 'two not made');
+
+is($one_defer->(), 'one', 'one (deferred) still runs');
+
+is(Foo->one, 'one', 'one (undeferred) runs');
+
+is(my $two_made = undefer($two_defer), $made{'Foo::two'}, 'make two');
+
+is($two_made, \&Foo::two, 'two installed');
+
+is($two_defer->(), 'two', 'two (deferred) still runs');
+
+is($two_made->(), 'two', 'two (undeferred) runs');
+
+my $three = sub { 'three' };
+
+is(undefer($three), $three, 'undefer non-deferred is a no-op');
+
+done_testing;