Hi all I'd like to share the attached PG_LSN.pm module that I use when writing TAP tests. I suggest that it be considered for inclusion in core.
It defines a Perl datatype PG_LSN with operator support, so you can write things like cmp_ok($got_lsn, "<", $expected_lsn, "testname") in TAP tests and get sensible results without any concern for LSN representation details, locale, etc. You can subtract LSNs to get a byte difference too. It's small but I've found it handy.
PG_LSN.pm
Description: Perl program