$req=Apache::FakeRequest::ViceRaid->new( method::lookup_uri => sub {
    # ... insert what you want it to do
 });

##</code><code>##

sub lookup_uri {
    $_[0]->{method::lookup_uri}->(@_);
}

##</code><code>##

sub lookup_uri {
    ($_[0]->{method::lookup_uri} || $_[0]->can(SUPER::lookup_uri))->(@_);
}