Hi :) For a development, I'm adding additional keys to C4::Reserves::CanItemBeReserved returned hash. But there are a bunch of tests that match the whole return value and thus don't expect the new keys in the hash. Here is the best way so far I've found to adapt it. is_deeply( CanItemBeReserved( $patron->borrowernumber, $itemnumber_2 ), { status => 'tooManyReservesToday', limit => 0 }, 'Patron cannot reserve if holds_per_day is 0 (i.e. 0 is 0)' ); ↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓ my @status_and_limit = @{CanItemBeReserved( $patron->borrowernumber, $itemnumber_2 )}{"status", "limit"}; is_deeply( \@status_and_limit, ['tooManyReservesToday', 0], 'Patron cannot reserve if holds_per_day is 0 (i.e. 0 is 0)' ); How could this be better? Since it took me more than two hours only to have something that works and without warnings. There are surely other ways to do it™, and hopefully a nicer one. Most of the time was reading and learning by trial and error about referencing and dereferencing and the specifics or Perl hashes and array. It's odd to have been working 3.5 years on Koha closer to the code than to the librarian stuff and only have to really start learning Perl now ^^ Away, this is why advice is needed to have something that fit the good practices :) Key/Value Hash Slices would allow to not change the expected param of is_deeply() but that doesn't really look different for the readability. And isn't worth having Koha bump minimal Perl version from 5.14 (2011) to 5.20 (2014). Ok it's just for running the tests and not production but still. -> very minor or inexistent readability improvement. https://perldoc.perl.org/perldata#Key/Value-Hash-Slices Having two assertions (is() calls) for status and limit would allow a simpler syntax but add duplication. Cheers, -- Victor Grousset/tuxayo