He expects http://a.b.c/d/../e/ to be the same as http://a.b.c/e/.
use Test::More tests => 1;
use URI qw( );
my $base1 = URI->new("http://a.b.c/d/../e/");
my $base2 = URI->new_abs("../e/", URI->new("http://a.b.c/d/"));
my $uri = URI->new("http://a.b.c/y");
not ok 1
# Failed test at a.pl line 12.
# got: '../../../y'
# expected: '../y'
# Looks like you failed 1 test of 1.
I don't see anything in http://cpansearch.perl.org/src/GAAS/URI-1.58/t/abs.t that covers this case.
The equality definitely doesn't hold up in file systems (due to links both soft and hard), but ../../../y is much less likely to be correct.
Update: Improved test a bit.